1 Evaluation of “Organic” Products and Home Remedies to Eliminate Red Imported Fire Ant Colonies - Bastiaan M. Drees and Paul R. Nester

11 Evaluation of Citrex® Fire Ant Killer as a Drench Treatment for the Red Imported Fire Ant Mounds - Paul R. Nester

15 Evaluation of Soygold® 1000 for the control of red imported fire ants -Elizabeth Hickman and Bastiaan M. Drees

17 Evaluation of Guest Control Inc. Weep-hole Screens for Brick Veneer Structures for Excluding Red Imported Fire Ant Workers - Bastiaan M. Drees

18 Evaluation of Repeated Annual Treatments of Broadcast Ant Baits in Hay Production Systems - Ronald D. Weeks, Jr., Michael E. Heimer, and Bastiaan M. Drees

22 Targeted Bait Treatments Around Stacked Bales of Hay to Eliminate Fire Ant Infestations - Ronald D. Weeks, Jr., Michael E. Heimer, and Bastiaan M. Drees

25 Chemical (Chlorpyrifos and Permethrin) Treatments Around Stacked Bales of Hay to Prevent Fire Ant Infestations - Ronald D. Weeks, Jr., Michael E. Heimer, and Bastiaan M. Drees

29 Geotactic Behavior of Female Alates of Red Imported Fire Ants on Quarantine Regulated Articles - Ronald D. Weeks, Jr., John G. Thomas and Bastiaan M. Drees

32 Beekeeper Evaluations of: 1) Broadcast Applications of Fire Ant Baits in Apiaries, and 2) Sampling Kit for Truckers and Haulers - Ronald D. Weeks, Jr., John G. Thomas and Bastiaan M. Drees

35 Prototype Ant Bait Blower Developed and Evaluated - Bastiaan M. Drees, Charlie G. Coble, Charles L. Barr, and S. Bradleigh Vinson

39 Red Imported Fire Ant Activity and Weather Reporting Program - Rody Best, and Bastiaan M. Drees

46 Community-Wide Fire Ant Management with Lakeview Country Estates in Mansfield, Texas - Elizabeth Ann Hickman

The reports contained herein were conducted for research and demonstration purposes. Some of the materials evaluated are currently not registered. Mention of these treatments or practices in these reports does not constitute a recommendation for this use.

In management information developed by Texas Cooperative Extension, any suggested pesticides must be registered and labeled for use by the Environmental Protection Agency and the Texas Department of Agriculture. The status of pesticide label clearances is subject to change. County Extension agents and appropriate specialists are advised of changes as they occur.

The USER is always responsible for the effects of pesticide residues on his/her premises, livestock or crops, as well as for problems that could arise from drift or movement of the pesticides from his property to that of others. Always read and follow carefully the instructions on the product label.

For more information regarding fire ant management, see Extension publications B-6043, Managing Red Imported Fire Ants in Urban Areas; B-6076, Managing Red Imported Fire Ants in Agriculture; B-6099, Broadcast Baits for Fire Ant Control; or L-5070 The Texas Two-Step Method Do-It-Yourself Fire Ant Control for Homes and Neighborhoods. Also visit our web site at http://fireant.tamu.edu.

The information given herein is for educational purposes only. Reference to commercial products or trade names is made with the understanding that no discrimination is intended and no endorsement by Texas Cooperative Extension or the Texas Agricultural Experiment Station is implied.

Educational programs conducted by Texas Cooperative Extension serve people of all ages regardless of socioeconomic level, race, color, sex, religion, disability or national origin.

Interest in home remedies and “organic” treatments for the red imported fire ant, Solenopsis invicta Buren, remains high. A number of home remedies such as soap solutions (Roberts 1987) and instant grits (Garrett, 1993) have been proposed or supported with anecdotal observations. However, few have actually been scientifically evaluated in formal field trials. Some products (Erath Earth Orange Oil, Erath Earth Gathering and Holding co., Hico, TX and Ridants®, CedarCide Industries, Inc., Spring, TX) are not pesticides registered by the Environmental Protection Agency (EPA), but are sold as “elixirs relating to plants and insects” or are promoted to control fire ants while claiming to be exempt from registration. The 25(b) clause of the Fungicide, Insecticide Rodenticide Act (FIFRA) allows products containing certain food grade active ingredients and inert ingredients to be exempt from FIFRA, which requires EPA registration provided they are approved for sale in Texas by the Texas Department of Agriculture (TDA) and have effectiveness proven through scientific evaluations (efficacy trials).

The series of trials reported herein were conducted to generate field data to align product or treatment performance with consumer expectations. Results are not intended to provide a basis for the endorsement or recommendation for use by the Texas Imported Fire Ant Research & Management Project, the Texas Cooperative Extension or the Texas Agricultural Experiment Station at The Texas A&M University System.

Trials were conducted on the Texas A&M University campus on grounds located near the George Bush Presidential Library. This area is regularly mowed and contained predominantly Bermuda turf grass. Plots were established by locating, and marking with field flags, sets of 10 red imported fire ant (henceforth referred to as the fire ant) mounds in areas of roughly equal widths and varying in length depending on fire ant mound density. Plot areas were calculated and arrayed from smallest to largest plot. Blocks of treatments were then established with one block (replication) containing the smallest plots, one block with medium-sized plots and one with the largest plots. This method accommodates fire ant colony movement through the course of the trial. Within each block, treatments were randomly assigned so that each trial’s treatments were replicated three times.

All treatments (Appendix 1) were applied from 1 gal jugs through a colander to break the flow into a gentle sprinkle to simulate a garden sprinkler. Additional mounds detected in plots at the time of treatment were marked with different colored flags to eliminate them from further evaluation.

Fire ant mounds were assessed using the minimal disturbance method, whereby mounds were disturbed with a field flag or shovel. When 12 or more fire ants emerged from the disturbed mound in a defensive reaction, the mound was considered to contain a fire ant colony. This method was used to establish plots and to evaluate treatments periodically following application of treatments. At the later post-treatment evaluations, an effort was made to assess other active fire ant mounds within treatment plots, thereby providing data on “new” or “satellite” mounds which result from colony movement. However, due to the appearance of many “new” mounds in plots and abandonment of untreated controls in both dry and water-drenched check plots, new mounds were recorded either for occurring within a 5 ft. radius of the treated and marked mound or occurring within the plot. The new mounds closer to the treated mounds were considered more likely to represent “satellite” mounds caused by fire ant colony migration or “shattering” of colonies whereby the treated colony split into two or more “new” colonies.

Trial 1. This trial was established on September 26, 2001 ranging in size from 5,320 to 14,570 sq. ft. Treatments were applied Sept. 27 in the afternoon, when the weather was clear and the high temperature reached 82 degrees F. Treatments included:

4) Liquid dishwashing detergent plus orange oil - 1 fl oz (2 Tbsp) Dawn plus 1 fl oz (2 Tbsp) Erath Earth Orange Oil

5) Citrex™ Fire Ant Killer - below labeled rate application of 3 fl oz/gallon (the new, low rate currently pending labeling is 5 fl oz/gal, pers. com. Craig Gant)

Trial 2. Plots were established on September 26, 2001 with additional treatment plots established on Sept. 28 and Oct. 4

2) Instant grits (Quaker® Instant Grits Original, The Quaker Oats Company, P. O. Box 049003, Chicago, IL 60604-9003) - 0.5 cup per mound, minimum (three plots treated Sept. 27 (I), 28 (II), and Oct. 1 (III), respectively).

Trial 3. Plots were established October 3 and 4, 2001 and treatments were applied from 10:00 a.m. to 1:00 p.m. on Oct. 4. Temperature was 86 degrees F and weather was clear. Treatments included:

3. CedarCide Pet, Horse & Livestock Concentrate - 1 Tbsp plus 1 tsp per gallon per mound.

In addition, five fire ant mounds were treated with TFA Super-Kill™ Fire Ant Eliminator using a sample and directions provided by the manufacturer. This treatment was not considered part of Trial 3 although mounds were drenched Oct. 4, 2001.

Data from all Trials were analyzed using analysis of variance (ANOVA) and means were separated using the Duncan’s Multiple Range Test at the 5 percent level of probability (Microstat, Ecosoft Inc., Indianapolis, IN).

No significant rainfall occurred until after October 5, with weather being mild (daytime high temperatures in the mid-80 and nights in the 60 degree F range) and dry. Soil moisture was fairly dry. Thereafter, rains saturated soils and brought fire ants to the surface and dramatically increasing the number of fire ant mounds in plots. In additions, many colonies in dry and water-drench control (check) plots relocated. As a result, we began recording fire ant mounds within a 5 ft radius circle of the originally treated mound.

Trial 1. Three days after treatment, all mound drench treatments, including a water-only treatment, significantly reduced numbers of active fire ant mounds relative to untreated (dry) control/check mound plot means (Table 1). The soap and water only treatments provided similar results as did the Citrex™ and citrus oil plus soap treatments, although the latter provided significantly better control. From 8 to 29 days after treatment, Citrex, soap and citrus oil plus soap treatments provided significant reductions of treated and marked fire ant mounds relative to both water-only and dry untreated plot means. Furthermore, when accounting for colony movement within a 5 ft radius of the treated mound site, the Citrex and citrus oil and soap treatments provided significant reductions of mound numbers. Due to the appearance of numerous “new” mounds within plots, no treatment provided significant reductions of fire ant mounds within plots 15 and 29 days following treatment.

Trial 2. Quaker® Instant Grits Original, applied at 0.5 cup per fire ant mound resulted in no significant reductions relative to untreated control (dry check) plot mean mound numbers over the 29 day duration of this trial (Table 2).

Trial 3. Although the number of treated and marked fire ant mounds drenched with CedarCide Pet, Horse & Livestock Concentrate were numerically reduced 1 day after treatment, the reduction was not significant (Table 3). Fire ant mounds treated with Ridants® were still active although the number of fire ants appeared to be dramatically reduced. Three days after treatment, the cedar oil containing products had significantly reduced active fire ant mound numbers relative to water only mound drench untreated control (check) plot means. Thereafter, new fire ant mounds appearing in plots eliminated significant differences between treatment plot fire ant mound numbers through the 29 day duration of this trial.

Interestingly, on the 15^th day after treatment (October 19), the treated and marked mound site plot means for the two cedar oil products were significantly lower than untreated check plot means. However, then the number of fire ant mounds within a 5 ft radius of the marked site was analyzed, more fire ant mounds were found in cedar oil drenched plots, with significantly more in plots treated with CedarCide Pet, Horse & Livestock Concentrate. These data imply that cedar oil products are, in fact, acting primarily as insect repellent products - not contact insecticides. Treated fire ant colonies not only relocated to nearby sites, but they also split into several fire ant colonies (a phenomenon also called shattering). This site is suspected of harboring the multiple queen (polygynous) form of the fire ant which are capable of colony splitting because each mound contains more than one reproductively active queen ant.

September and October are the rainiest months of the year in College Station, Texas (Figure 1). At this time fire ant colonies that have been dwelling deeper in the soil and not producing visible mounds begin to work towards the surface seeking warmer soil or escaping saturated soils from recent rains. Freshly-built mounds are evidently not stable in their location and fire ant colonies frequently move, evidently in search of better nesting sites or escaping any type of irregularity, i.e., disturbance, disease, predators, etc. Their mounds are not well constructed with “honey-comb” galleries characteristically built by ant species inclined to stay in one location for longer periods of time. However, these more transient fire ant colonies build mounds of freshly-dug earth piled on top of turf grass. Thus, the strategy of locating and treating visible mounds misses the colonies dwelling underneath the soil surface, and treated colonies readily abandon mounds and produce new ones in the near vicinity.

Use of fire ant mound numbers as an indicator of fire ant populations has been brought into question, in part, because of the experience gained by conducting these three Trials. Perhaps it is better to think of fire ant mounds as bubbles in boiling water or as glass balls in a Galileo liquid thermometer which rise to the surface under specific conditions. However, as relative indicators of ant fire ant population levels between treatments at a given point in time, ant fire ant mound numbers can still be an appropriate measure.

Trial 1. Plant oils, as those contained in citrus peels (d-limonene), pine (turpentine) and cedar are known to contain ingredients toxic to some insects. Soaps contain surfactants that can cause direct insect mortality by suffocating or drowning pests and can also act as emulsifiers to allow oils to be mixed into water. Soaps also cut through the wax-covered insect exoskeleton allowing active ingredients in oils to penetrate and act to kill cells (cytotoxicants). This effect can be seen in the results of Trial 1 where the 2 fl oz rate of liquid dishwashing detergent eliminated fewer active ant mounds than did the treatment containing half that amount of detergent (1 fl oz) plus 1 fl oz orange oil.

Plant oil and soap drench treatments must directly contact the target pests in order to eliminate them. In these trials, one gallon of solution was used to treat each fire ant mound, regardless of its size. Larger fire ant mounds were less likely to have all fire ants eliminated by any of the liquid drench treatments, although the number of worker fire ants emerging from minimally disturbed mounds were far fewer in number following treatments than in water drenched or untreated (dry check) mounds. Thus, the evaluation of active or non-active mounds is a fairly stringent measure of product performance requiring virtually all fire ant activity in treated mounds to be eliminated before it was determined to be inactive.

Trial 2. Use of instant grits has been reported to eliminate fire ant colonies by users for a long time, and some people are adamant about their observations. However, the results from use of any fire ant mound treatment is extremely difficult to assess without conducting a replicated, statistically analyzable trial. The results of these trials have pointed to some of these difficulties. In Trial 1, even application of one gallon of tap water drenched on fire ant mounds resulted in some numerical reduction of mounds at treated sites compared to the dry untreated control (check) plot fire ant mound means (Table 1). This field trial provides further documentation that this home remedy is ineffective as a fire ant treatment.

Trial 3. Ridants, applied as directed, appears to repel fire ant colonies from treated sites within three days of application. However, colonies do not appear to be eliminated. When a higher concentrated cedar oil product (CedarCide Pet, Horse & Livestock Concentrate - not currently promoted for fire ant control) was used, treated fire ant mounds split as well as relocated, resulting in more fire ant mounds near the one treated initially. Use of this product for managing fire ants should be carefully thought through. As a repellent, this product may be useful for rendering certain locations, such as potting media, temporarily fire ant free. However, resulting fire ant colony relocation and splitting following treatment makes use of these treatments unlikely for use to reduce fire ant populations.

As with any field trial to assess the effectiveness (efficacy) of fire ant control products, confidence in the results presented here can be improved by conducting additional replicated trials at different locations and times of the year.

Garrett, H. 1993. Texas Organic Gardening Book. Gulf Publishing Company. Houston, Texas. (p. 140) 245 pp.).

Roberts, T. 1987. Soap solutions vs. the fire ant. The IPM Practicioner IX(6-7), p. 17.

The authors are grateful for permission to use this site for conducting these evaluation, with permission provided by Thomas W. Dew, Jr., Superintendent for Landscape and Pavements Maintenance with the Physical Plant Department Facilities Maintenance & Renovation of Texas A&M University (979/845-5511; FAX: 979/458-0456; e-mail: t-dew@tamu.edu, with cooperation from Tommy Palmos and Mike Faust. Products for evaluations were graciously provided by Dave L. Glassel, CedarCide Industries, Inc and Craig Gant, EnviroSafe Labs, LLC.

New Fast Acting Formula Ultra Dawn Original Scent (1.48 l (1.56 qt) or 50 fl oz. container for $3.58). Dawn contains biodegradable anionic and nonionic surfactants and no phosphate. (Proctor & Gamble, Cincinnati, OH 45202; 800/725-3295)

Erath Earth Orange Oil ($13.95/1 qt (0.95 l.; 1 to 2 oz. per gal. for foliar spray or 6 to 8 oz. per gal soil drench application rates). Cold press orange peel extract is one of the best oils for use in the preparation of organic elixirs relating to plants and insects. (Erath Earth Gathering and Holding co., Rt. 2, Box 11, Hico, TX 76457)

Citrex™ Fire Ant Killer (d-limonene (7.2 lbs./gal.) 78.2%; 32 fl. oz.; 8 fl. oz./gal/mound application rate). Do not disturb mound prior to applying mixture. Mix with water according to the dilution chart. Apply the mixture in the early morning before ants become active. Apply the mixture in a circular motion starting at the base of the mound and continuing to the top of the mound. Make sure fire ant mound is completely saturated. Mix only enough to use at one time. Do not store mixture overnight; avoid contact with eyes or clothing. (WARNING, EPA Reg. No. 72244-1-72440).(EnviroSafe Labs, LLC, 210 North Loop 336 East, Conroe, TX 77301; www.envirosafelabs.com)

Ridants® (0.004 cedar oil; retail price: $4.99/gal ready-to-use; 1 gal. (3.787 l)/mound application rate). Carefully wipe the ant mound with a long handled shovel or rake, exposing the ant eggs. This is best done in the heat of the day. Drench the mound and surrounding area with Cedarcide Ridants. For greater coverage dilute 1 gallon of Ridants with 4 gallons of water (optional). To insure results, drench exposed tunnels 12 to 24 hours later. To prevent reinfestation of ants or other insects apply CedarCide Pesticide Granules in desired areas. For economical treatment of multi-acre infestations, soak 1 part CedarCide granules with 3 parts water for a 48 hour period, use the unpurified solution in the same manner described above. This product is classified as a minimal risk pesticide by the Environmental Protection Agency of the U.S.A. ruling 40CFR 152.25 not intended for tick control. Promotional literature statements - “Put an end to fire ants without danger to humans or animals. Apply this liquid direct or dilute it for larger mounds. Ants digest the special formula while salivating the soaked soil, a process used to repair their destroyed mound. As the worker ants become ill, reinforcements are called upon until all the ants are dead. CedarCide granules in your yard will repel ants and eliminate infestations. For large colonies of ants, we suggest brewing a batch of your own liquid from granules. Directions on bag. (Dave L. Glassel, Founder and CEO, CedarCide Industries, Inc., P. O. Box 549 Spring, TX 7783; 800/842-1464, www.cedarcide.com)

CedarCide Chemical Free Pure Cedar Oil Pet, Horse & Livestock Concentrate (50% cedar oil; 1 qt container). Mix ½ pint for 25 gallons of water; dilute solutions 400 to 1 for gardening use; safe to use directly on fruit and vegetables; repels numerous insects including ants; CAUTION - avoid contact with eyes; do not take internally; wash hands with soap and water after use; keep out of reach of children. CedarCide 66/33 concentrations are approved as a minimum risk pesticide by the EPA 40CFR 152.B.)(Dave L. Glassel, Founder and CEO, CedarCide Industries, Inc., P. O. Box 549 Spring, TX 7783; 800/842-1464, www.cedarcide.com)

TFA Super-Kill™ Fire Ant Eliminator (pine oil 89%; 32 fl. Oz; 5 ounces (5/8/ cup) per gallon per mound application rate) Shake well before using; pour mixture onto the ant mound starting at the perimeter and continuing in a circular motion to center of the mound; do not disturb the mound before treatment; apply product gently to avoid disturbing the ants; use one gallon of mixture per ant mound; confine mixture to the area of the ant mound in applications to lawns; product may cause browning of, or kill, grass around edges of ant mounds; for best results, use during cooler parts of the day, early to mid-morning, and not during prolonged hot and dry conditions. Precautionary statements - corrosive, causes eye damage; harmful if swallowed; causes skin irritation; do not get in eyes, on skin or clothing; wear goggles or face shield and rubber gloves when handling; wash thoroughly with soap and water after handling; do not store near heat or open flame.(TFA Products, Inc., Houston, TX 77079, DANGER, EPA Reg. No. 70072-1)

Table 1. Red imported fire ant mound numbers per 10 mound plot and per plot following September 27, 2001 application of an “organic” product and selected home remedy ant mound drench treatments, Brazos Co., TX.

^a Means in columns followed by the same letter are not significantly different using ANOVA and separated using the Duncan’s Multiple Range Test at the 5% level; NS = not significant (Microstat).

^b Number of active mounds out of 10 marked and treated; indented - including the number of active mounds withing 5 ft radius of treated mound considered to be “satellite” mounds; and, double indented - total number of active mounds per plot.

Table 2. Red imported fire ant mound numbers per 10 mound plot and per plot following September 28 through October 1, 2001 application of o.5 cup instant grits to three of six plots, Brazos Co., TX.

^a Means in columns followed by the same letter are not significantly different using ANOVA and separated using the Duncan’s Multiple Range Test at the 5% level; NS = not significant (Microstat).

Table 3. Red imported fire ant mound numbers per 10 mound plot and per plot following October 4, 2001 application of cedar oil-containing liquid drench products, Brazon Co., TX.

^a Means in columns followed by the same letter are not significantly different using ANOVA and separated using the Duncan’s Multiple Range Test at the 5% level; NS = not significant (Microstat).

Summary. The red imported fire ant, Solenopsis invicta Buren, (herein referred to as the fire ant) has become an important economic threat in urban Texas. The fire ant affects recreational activities as well as agricultural operations. This trial evaluated a product that contains a botanically derived insecticide, d-limonene, as a single mound treatment fire ant mounds, at lower-than-labelled rates, on the premises of the Johnson Space Center (JSC) of the National Aeronautics & Space Administration (NASA) in Houston, TX. The data indicates that Citrex® at the 3, 4 and 5 oz/gal rate, when compared to the untreated check, reduced mound activity within 3 days after treatment (DAT). This reduction was still evident 14 (DAT), with the 4 and 5 oz/gal rates having fewer active mounds than the 3 oz/gal rate. This trial was applied April 27, 2001 when temperatures were moderate, moisture was good and fire ant activity was good. This trial demonstrates that the 4 and 5 oz/gal rates are effective in reducing fire ant mound activity as single mound treatments.

Problem. The red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae), has become an important economic threat in urban Texas. According to a 1998 study conducted by the Department of Agricultural Economics, TX A&M University, of fire ant related costs in Dallas, Fort Worth, Austin, San Antonio, and Houston, fire ants have serious economic effects for these metro areas of Texas. Households experienced the largest costs among sectors examined with a average of $151 per households spent annually which included repairs to property and equipment, first-aid, pesticides, baits, and professional services. A full damage assessment for Texas, including additional sectors, is estimated at over $1.2 billion per year. Treatment costs accounted for over 50% of the total cost of $581 million in the five major metroplex areas (Dallas, Fort Worth, Houston, Austin and San Antonio). In Houston, the average medical treatment costs per household of $25.46. The fire ant limits outdoor activities and homeowners and producers incur added costs in managing the fire ant.

Citrex® Fire Ant Killer, containing 78.20% d-limonene (an extract from oil from citrus peels) plus an emulsifier inert ingredient (Surfonic N-95), by Envirosafe Laboratories was introduced in August 1999. This product is considered to be an "organic" treatment. In 2000, the label rate was 8 fl oz per gal water. At $15.49/32 fl oz (2002 price), the per mound treatment cost using 8 fl oz/1 gal per mound, the per mound treatment cost was $3.87. Furthermore, treatments were observed to cause discoloration and death (phytotoxicity) of common turf grasses like Bermuda and St. Augustine grass. In contrast, one of the least expensive individual mound treatments is acephate. For Ortho® Orthene® Fire Ant Killer (50% acephate), applied at 1 Tbsp/mound, 1 lb treats 80 mounds. At $13.77/lb, the treatment cost is $0.17 per mound.

Objectives. This trial was established to evaluate several lower rates of Citrex® Fire Ant Killer as a single mound treatment for fire ants to reduce treatment cost and phytotoxicity problems associated with treatments. The trial was designed to observe the effectiveness of concentrations of product below the 8 fl oz/gal labelled rate in 1999-2000 in reducing fire ant activity and phytotoxicity over a two week period. Furthermore, reduced volumes of the diluted product below the conventional 1-gallon per mound amount used in this trial offer further reductions in treatment cost. This effort could help lower the treatment cost for fire ant control in turfgrass areas statewide.

On Thursday, April 26, 2001 on the premises of the JSC and NASA in Houston, TX, approximately 280 active fire ant mounds were identified and flagged in an area approximately 120 ft x 900 ft. The mounds were located by walking back and forth the length of the area in 15-ft widths. Mounds were considered active if more than 100 aggressive fire ants surfaced within 10 sec of probing the mound with the surveying flag wire.

On Friday, April 27, 2001, 240 active fire ant mounds were divided into 24 plots of 10 mounds each. The 24 plots, each containing 10 active fire ant mounds, were then marked with a second identifying flag to be either left untreated, treated with Surfonic N-95 (surfactant), treated with Ortho® Orthene® Fire Ant Killer or treated with Citrex® Fire Ant Killer. Plots were randomly selected in oval groupings for 4 repetitions of each of the various treatments. All mounds were then treated between 12:00 pm and 4:00 pm. Treatments included:

The Surfonic N-95, the inert ingredient in Citrex®, and Citrex® Fire Ant Killer (EPA Reg. No. 72244-1) were mixed at the above concentrations in 2.5 gal containers. Application was made to the mounds using 2-qt plastic pitchers. Two quarts were applied to each mound (exceptionally small mounds received 1 qt and unusually large mounds received 3 qt or 1 gal) by starting from the outside edge of the mound and working towards the center of the mound in a circular motion causing the mound to collapse in from the center. Only enough of the Surfonic and Citrex® mixture was used to saturate the mounds. The label rate (1 Tbsp/fire ant mound) of Orthene Fire Ant Killer (EPA Reg. No. 239-2632) was sprinkled on the designated mounds and watered in with 2 qt of water.

On April 28 & 30, and May 4 & 11, 2001, all 240 mounds were inspected starting at 10:00 am and finishing around 2:00 pm. Mounds were probed with a wooden stick and closely inspected for fire ant activity. If after 15 sec ants were seen coming out of the probed mound, the mound was considered active (Table 1). Inspection for new ("satellite") mounds occurring within 2 to 3 ft of treated mounds was made. Satellite mounds, mounds that appear within 5 ft of treated mound, were counted and data are presented in Table2.

All rates of Citrex® significantly reduced the number of active mounds when compared to the untreated check at each of the evaluation dates (Table 3). Statistically, the 4 and 5 oz/gal Citrex® rates performed identically and produced significantly quicker elimination of ants in treated mounds than the 3 oz/gal rate in reducing mound activity 3 days after treatment (DAT) and lower mound activity from these higher rates was still seen at 7 and 14 DAT. Satelite mounds were also found around more of the 3 oz/gal treated mounds, than the 4 and 5 oz/gal treated mounds (Table2).

Table 1: Active fire ant mounds. Raw data from Citrex® Fire Ant Killer Field Test Results, NASA, 2001.

Mound Treatment	Day 1	Day 3	Day 7	Day 14
untreated	-	-	-	-
Surfonic N-95	0	0	0	4
Orthene®	0	0	0	1
Citrex® 3 ounce	0	4	4	6
Citrex® 4 ounce	0	0	0	3
Citrex® 5 ounce	0	0	0	1

Table 3. Citrex® Fire Ant Killer Field Test Results, NASA, Galveston Co., Texas, treated April 27, 2001.

* Means in columns followed by the same letter are not significantly different using analysis of variance (ANOVA) at P < 0.05 and separated using Duncan’s Multiple Range Test (Microstat).

All 240 mounds were also inspected on each evaluation date for signs of plant damage. The field was a mixture of Bermuda grass, St Augustine, wild flowers and other unknown grasses and weeds. On a scale of 0 to 10, with 0 being no damage and 10 being death of foliage the following was noted:

Mound Treatment	Day 1	Day 3	Day 7	Day 14
(U): untreated	0	0	0	0
(N): Surfonic N-95	0	0	0	0.5
(O): Orthene	0	0	0	0
(3): Citrex® 3 ounce	0	0	2	1
(4): Citrex® 4 ounce	0	0	3	2
(5): Citrex® 5 ounce	0	0	4	3

In total, 120 mounds were treated with Citrex®. No sign of phytotoxicity was noted on either Day 1 or Day 3. Day 7 produced some yellowing/reddening of the vegetation on some of the mounds treated with Citrex®. All of the mounds treated with Citrex® still showed phytotoxicity symptoms on Day 7, but by day 14 these symptoms weres less evident. The use of Citrex® at any of the applied solutions may cause yellowing to residentisl lawns. The higher the rate the more intense the symptoms.

Results from this limited study showed that rates of Citrex® Fire Ant Killer as low as 3 oz/gal will reduce fire ant mound activity. The 4 and 5 oz/gal rates gave the highest reduction in activity with reduced phytotoxicity problems. The rate of 5 oz/galof Citrex® was labeled in 2002 as a result of this study, was effective in reducing the activity of treated fire ant mounds. However, data suggested that the 4 oz/rate may be considered just as effective and could offer the user a slightly more economical means treating fire ant mounds. This rate is being considered for the future revision of the product's label. The 4 fl oz/gal rate would cut the cost of the product in half, to $1.94.

Furthermore, although the amount of volume used to drench each mound with these low rates of Citrex® were not recorded for each mound treated in this trial, application of less than one gal dilute drench per mound could result in additional reductions in treatment cost. For instance, treating a "small" ant mound with a quart of material would cost $0.48, which is comprable to many other individual ant mound drench products currently on the market.

The author would like to thank Mr. Craig Gant and EnviroSafe Labs, Conroe, TX, for the Citrex® product used in this study and his help in establishing and evaluating this study.

The red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae), is a major economic pest in Texas. Surveys conducted by the Department of Agricultural Economics and the Texas Agricultural Statistics Service have estimated the total annual fire ant damages and expenditures for Texas to be 1.2 billion dollars.

This trial evaluated one experimental and one currently available individual ant mound drench treatments to control red imported fire ant colonies. The trial was established at the home and acreage of Mr. E.J. Dane in Denton County on April 30, 2002.

Objectives. This trail was established to evaluate the experimental product Soygold® 1000 Multi-Purpose Industrial Solvent (containing fatty acid methyl esters of soybean oil) and compare it to known effective individual mound treatments currently available for the control of fire ants, Citrex® (containing d-limonene). This trial was designed to observe the effectiveness of this material over a period of 30 days.

This trial took place at the home of E.J. Dane of Argyle, Texas. The home of Mr. Dane is located on the front section of the property with a pond behind the home and a section of land behind the home with cows, horses, and goats on it. The section of land which was home to the animals was the area the trial took place.

Twelve plots of similar width but varying in length, each containing 10 imported fire ant mounds, were established, April 20, 2002. Plot numbers were arrayed from longest to shortest and divided into 4 blocks or replicates of three plots each, with one replicate containing the longest plots, one containing the shortest plots, and two intermediate blocks. Plot corners were marked with colored flags and mounds in that plot were marked with the corresponding color of flag. This method assured that re-invasion of ant colonies migrating from outside plots would be similar for all treatments. Plots 1,5, 7, 9 (74, 54, 129 and 101 ft long, respectively) were designated Soygold® 1000 plots and each mound was treated with one gallon of undiluted product applied through a colander to simulate a mound drench applied using a water sprinkler can applied treatment; plots 2,3,8,11 (185, 85, 54 and 42 ft long, respectively) were untreated check plots in which each ant mound was treated with1-gallon water, only, drench; and plots 4, 6,10, 12 (98, 148, 42, and 62 ft long, respectively) were treated with Citrex® (d- limonene) at a dilution of 4 fl oz per gallon of water applied to each ant mound.

At 2, 7, 14, and 30 days after treatment, ant mounds were disturbed and evaluated for ant activity, if any. If a dozen or more worker ants emerged from slightly disturbed mounds withing about 30 seconds, the colony was determined to be active. On day 30 following treatment, the number of “new” colonies appearing within treatment plots were also assessed to document if treated ant colonies may have moved to new locations or split into more than one colony. Data was analyzed using analysis of variance (ANOVA) at P < 0.05 , and means (average plot values) were separated using and separated using Duncan’s Multiple Range Test (Microstat).

Both ant mound drench treatments (Soygold® and Citrex®) significantly reduced ant activity in treated mounds relative to mounds in the untreated check plots (Table 1). The two treatments performed the same, statistically. Grass around mounds treated with Soygold was killed. At the 30 day post-treatment evaluation, no re-growth was noted.

Table 1. Soygold and Citrex Fire Ant Killer Field Test Results, Denton, TX, 2002.

* Means in columns followed by the same letter are not significantly different using analysis of variance (ANOVA) at P < 0.05 and separated using Duncan’s Multiple Range Test (Microstat).

This trial was supported, in part, by Ag Environmental Products, L.L.C., 9804 Pflumm, Lenexa, KS 66215. The support and assistance provided in establishing this trial by Doug Pickering was much appreciated.

Bastiaan M. Drees, Coordinator, Texas Imported Fire Ant Research & Management Project

The red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae) enters structures such as homes and relay switch boxes. Major and minor worker ants range in size from 5 to 1.5mm , and the head widths of the smallest workers can be 0.5 mm. They were unable to escape from vials with 0.6 mm diameter holes drilled in the caps (Drees 1995). The Guest Control Inc. (9762 Leopard, Corpus Christi, Texas 78410; 361/241-7939 or 866/580-5588; www.guestcontrol.com) Weep-hole Screens for Brick Veneer Structures are to be positioned around the holes at the base of walls and sealed in place using silicone glue. The screen provided is removable for cleaning. The assay described below was conducted to determine if this screen was capable of excluding red imported fire ant workers.

The Guest Control Inc. screen was cut into a circle and placed in a plastic 35 mm photographic film container with a 5 mm hole drilled into the bottom and sealed in place using silicone glue. Red imported fire ants (about 1 Tbsp.) were collected from a laboratory colony and placed in the container. The container was capped and placed in a zip-lock plastic sandwich bag. After 24 hours, the plastic bag was inspected for the presence of worker ants.

To determine screen size capable of excluding imported fire ant workers, a SS SandShaker Mechanical Sieve Field Analysis Kit (Kleck Instruments, Inc., 1099 West Grand River Ave., Williamston, MI 48895; 800/542-5681) was configured using an array of screen sizes provided: 1) No. 24 - 0.026 inch or 0.66 mm mesh opening; 2) No. 30 - 0.020 inch or 0.51 mm mesh opening; 3) No. 40 - 0.015 inch or 0.38 mm mesh opening; and 4) No. 60 - 0.009 inch or 0.23 mm mesh opening. Ants were placed in the unit with the largest mesh screen and allowed to enter units with progressively smaller mesh screens for 4 days (Dec. 14 to 17, 2002).

No worker ants escaped from the container sealed with the screen provided with The Guest Control Inc. after 24 hrs. Worker ants were capable of crawling through screen mesh as small as 0.020 inch or 0.51 mm but not through the 0.15 in or 0.38 mm mesh screen.

Drees, B. M. 1995. Exclusion of ants using holes of various diameters in Red Imported Fire Ant Management Applied Research/Result Demonstrations 1994-1995 p. 41.

Abstract. This research evaluated the efficacy of using two annual applications of broadcast insecticide baits in hay production systems to reduce field infestation levels of the red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae). Specifically we were interested in quantifying whether there was an additive effect of using an insect metabolic inhibitor (Amdro®, hydramethylnon), a proven ant bait, annually to field plots to reduce the number S. invicta infestations in hay bales in treated versus untreated field plots. These results and previous results have shown that with a single annual broadcast bait application of Amdro® Pro Fire Ant Bait (hydramethylnon) the number of hay bales infested with fire ants are significantly lower in treated plots compared to untreated plots. However, a second bi-annual application of Amdro® did not significantly reduce ant infestation levels on hay bales compared to the previous years reduction. These results indicate that treated fields were re-infested with S .invicta within a single year and there was no detectable additive affects of treating field plots annually with typical broadcast applications of insect metabolic inhibitors (e.g. Amdro®) in this study.

The red imported fire ants, Solenopsis invicta Buren (Hymenoptera: Formicidae) frequently moves into or next to bales of hay that have been left in the field after harvesting and their mounds can interfere with cutting, baling, handling and transporting hay. Typically, red imported fire ants build large hard-packed mounds above the ground, which can damage harvesting machinery. As a result, hay producers have to adjust the cutting heights on their harvesting machinery to avoid damage by mounds, resulting in reduced yields and increased harvesting costs. The United States Department of Agriculture (USDA) has listed hay as a quarantined agricultural product. Currently, there are no USDA approved quarantine chemical treatments for assuring that red imported fire ants are not shipped to new locations. Hay bales that are not removed from fields immediately after baling and stored in an off-ground location can not be shipped out of quarantined areas.

Previous research, conducted by us, has shown that a single broadcast application of Amdro® Pro Fire Ant Bait (hydramethylnon) in hay fields significantly reduced the level of hay bale infestations by S. invicta in treated areas compared to untreated areas (http://fireant.tamu.edu/research/arr/category/site/97-01pg42/97-01pg42.pdf). However, the single application did not eliminate the fire ant problem entirely. This suggests that not all colonies were eliminated in treated areas. Previous work has shown that periodic broadcast applications of fire ant baits can provide roughly 90 percent suppression of ants when properly applied. Given that we were not able to eliminate fire ants from our treatment plots we are encouraged by our initial results using a single application of an insect metabolic inhibitor Amdro®, hydramethylnon. Based on these significant results we were interested in continuing this study to assess the long-term efficacy of broadcast bait applications in a repeated treatment program of broadcast bait applications of Amdro®. Our goal was to determine whether a repeated spring application of Amdro® would reduce the instance of ant infestation to levels below those realized in the first years study.

For this study we used field plots previously established and treated in May 2000. This research was conducted May - July, October 2001 in Montgomery County, Texas. Two hay fields (1 square bale and 1 round bale production field), of at least 15 acres in size, belonging to 2 independent hay producers were used as replicate sites for this study. Each field was divided in half to make two plots of relatively equal size. In 2000, one plot in each field was designated as an insecticide treatment plot, while the other plot was left untreated and used for ant infestation comparisons between treated and untreated areas. We used the same fields and plot assignments for our 2001 studies.

In each field, one plot was re-treated with a broadcast application of the insecticide bait product Amdro® Pro Fire Ant Bait (hydramethylnon), to re-establish large areas where ants were suppressed in May 2000. The broadcast insecticide application rate was 1.5 lbs./acre as directed on the product label. The smallest area treated in a field was 5 acres. We compared both round and square bale operations. In the round bale operations, four sets of hay bales comprised of five round bales per set were left in each plot after hay baling (5 bales x 4 sets x 2 plots per field = 40 round per field). In the square bale operations, four random sets of hay bales comprised of ten square bales per set were left in each plot after hay baling (10 bales x 4 sets x 2 plots per field = 80 bales per field). Each hay bale was sampled for fire ants using two 2.5 x 2.5 cm olive oil-soaked bait cards placed on opposite sides of each bale, halfway up the side. Sampling was conducted at two separate times after baling (4 - 8, and 12+ days). The number of infested hay bales, per set of bales, was recorded for each sampling period. Infestation was scored as a positive when S. invicta was recorded on bait cards. We used the total number of hay bales, per set of bales, infested with red imported fire ants after being in the field for 12+ as our response variable. We combined the data from both square and round bale operations into a single data set for two non-parametric tests.

A) We used a Wilcoxon rank sum test to test the directional hypothesis that our repeated broadcast bait treatments significantly reduce or eliminate infested bales in treated compared to untreated areas.

B) We used a Wilcoxon rank sum test to test the directional hypothesis that repeated broadcast bait treatments significantly reduce the occurrence of infested bales compared to reduced levels from the previous year’s single application results.

Similar to the results obtained in 2000, we were not able to completely eliminate fire ants from the hay production operation. However, results of the Wilcoxon rank sum test support our directional hypothesis (A) that broadcast applications of the insect metabolic inhibitor, Amdro® Pro Fire Ant Bait (hydramethylnon), significantly reduce the number of infested hay bales in treated areas compared to untreated areas (Table 1).

Table 1. Results of a Wilcoxon rank sum test comparing the mean number of hay bales, per set of bales, infested with red imported fire ants after 12+ days in insecticide treated versus untreated hay fields; N = sixteen sets of hay bales in each treated and untreated area, of these eight sets comprised ten square bales per set and eight sets comprised five round bales per set in each treated and untreated area.
Treatment	N	Score Sum	Score mean	Sample mean	S	Z	P >\|Z\|
Treated	16	172.5	10.7	2.4
Untreated	16	355.5	22.2	6.7
Test Statistic					355.5	3.47	0.00025

We were not able to detect any additive effect of repeated annual broadcast bait treatments on the number of infested hay bale in this study (B). Results of the Wilcoxon rank sum test do not support our hypothesis that after a repeated broadcast application of Amdro® the number of infested hay bales in treated areas was significantly reduced compared to 2000 results (Table 2).

Table 2. Results of a Wilcoxon rank sum test comparing the mean number of hay bales, per set of bales, infested with red imported fire ants after 12+ days in insecticide treated hay fields treated in May of 2000 and 2001; N = eight sets of hay bales in each treated area, of these four sets comprised ten square bales per set and four sets comprised five round bales per set in each treated in both 2000 and 2001.
Treatment	N	Score Sum	Score mean	Sample mean	S	Z	P >\|Z\|
Treated	8	57	7.12	2.75
Untreated	8	79	9.87	3.87
Test Statistic					79	1.14	0.2538

We were not able to reduce infestation levels of S. invicta in hay bales in our repeated treatment (2001) program compared to levels observed in the first year of treatment (2000). Our results show that S. invicta was able to reinvade our treated areas within the year between bait applications. S. invicta can invade open areas, such as treated areas after baits have disappeared, by moving unaffected colonies into the area, budding, and through mating flights (swarms) and independent queen recruitment. Given that our bait applications were conducted in the spring (May) of both years it seems reasonable to assume that ant colonies were able to reinvade during a fall reproductive period. If so, this suggests that another repeated application in the fall may have had a better opportunity to reduce field reinvasions.

A single broadcast application of Amdro® Pro Fire Ant Bait in hay fields can significantly reduced the level of hay bale infestations in treated areas. However, it does not eliminate the fire ant problem entirely. This type of result suggests that not all colonies are eliminated in treated areas. Previous work has shown that periodic broadcast applications of fire ant baits provide roughly 90 percent suppression of ants when properly applied. However, given that we were not able to eliminate fire ants from our treatment plots we are still encouraged by our repeated results using a single application of Amdro®. Based on these significant results, we are interested in assessing the long-term efficacy of broadcast bait applications in a spring and fall repeated application program of treatment, or using sequential or hopper blend treatment of this product plus an insect growth regulator bait formulated product such as Extinguish® (s-methoprene). Our goal remains to develop reasonable treatments to assure shipment of ant-free hay bales from ant-infested to non-infested areas of the country.

Funding for this research was provided to Michael Heimer, County Extension Agent, Agriculture, Montgomery County, Texas through the Texas Department of Agriculture and the Texas Imported Fire Ant Research and Management Project. Thanks to Dr. White, and Mr. Berkeley, for hay and field sites and to Mr. Kyle Miller at American Cyanamid for the Amdro® donation. Thanks to Dr. Charles Barr for bait application support and equipment use.

Abstract. This research evaluated the efficacy of using an insect metabolic inhibitor (Amdro®, hydramethylnon) strategically applied around the base of stacked hay bales to eliminate red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae), infestations in stacked hay. We set-up 12 stacks of hay bales (six bales per stack) in a fire ant infested field and allowed them to become infested with fire ants. After three months, all twelve stacks became infested with colonies. We randomly selected half of the infested stacks to be treatment stacks and the remaining stacks served as controls for the experiment. Bait treatments consisted of applying 5 Tbsp. of Amdro® Pro Fire Ant Bait (hydramethylnon) around the base of randomly selected treatment stacks. Six weeks after bait applications, treated and control stacks of hay were sampled for ant infestation by visual cues, such as the presence of colonies on the stacks, and bait stations were used to collect ants on the second layer of hay of each stack. Of the six treated stacks, two stacks were “clean” of ants six-weeks after bait applications. However, results show that there was no significant difference in mean infestation levels between treated and untreated stacks.

The red imported fire ants, Solenopsis invicta Buren (Hymenoptera: Formicidae), frequently moves into or next to bales of hay that have been left in the field after harvesting and their mounds can interfere with the transportation hay. The United States Department of Agriculture (USDA) has listed hay as a quarantined agricultural product. Currently, there are no USDA approved quarantine chemical treatments for assuring S. invicta are not shipped to new locations. Hay bales that are not removed from fields immediately after baling and stored in an off-ground location can not be shipped out of quarantined areas. S. invicta are known to move colonies next to upright-exposed structures for better colony thermoregulation and to escape localized flooding events (Fig. 1). Previous research, conducted by us, has shown that hay bales left in the field can become infested in untreated areas within a few days to weeks after baling (http://fireant.tamu.edu/research/arr/category/site/97-01pg42/97-01pg42.pdf). The objective of this study was to evaluate the efficacy of using targeted baits applications of Amdro® around stacked bales of hay to eliminate hay infestations.

Stacks of hay were comprised of six square hay bales, stacked two a side in three interlocking tiers. Twelve stacks of hay were placed in a block design, of four stacks in three blocks, in a fire ant infested field on July 31, 2001 in Montgomery County, Texas (Fig. 2). By October 3, 2001 all stacks had become infested. Of these, we randomly selected half of the stacks in each block to serve as treatment stacks and the other stacks served as controls for the experiment. Bait treatments were applied during good ant foraging conditions (25º -30ºC) on October 3, 2001. Treatments included applying 5 Tbsp. of Amdro® Pro Fire Ant Bait (hydramethylnon) around the base of selected treatment stacks. Treatment and control stacks were sampled for ant infestation 6 weeks (November 14, 2001) after bait applications. Stacks of hay were sampled for ant infestation thorough visual inspection of stacks for ant mound building and using 2.5 x 2.5cm index cards soaked with olive oil pinned on the side of the second layer of hay in each stack. We used a directional Wilcoxon rank sum test to test the hypothesis that our targeted bait applications around stacks of hay would significantly reduce or eliminate infested bales in treated compared to untreated stacks.

There was no significant difference in ant infestation levels between treated and untreated stacks of hay (Table 1). However, the result was not a total failure. Six-weeks after testing positive for ant infestations, we were unable to detect any ant infestations in two stacks treated with 5 Tbsp. of Amdro® Pro Fire Ant Bait around the base of the stacks. All of the control stacks that had ant infestations at the time of bait application also had ant infestations and the end of the study.

Table 1. Results of a Wilcoxon rank sum test comparing the mean number of hay bale stacks, per block of stacks, infested with red imported fire ants six-weeks after 5 Tbsp. of Amdro® Pro Fire Ant Bait was applied around the base of selected treatment stacks; N = 3 blocks of hay stacks with two treated and two untreated stacks per block. Ants were sampled with oil-soaked bait cards for 45-minutes on the second tier of hay in each stack.
Treatment	N	Score Sum	Score mean	Sample mean	S	Z	P >\|Z\|
Base treated stacks	3	7.5	2.5	1.33
Untreated stacks	3	13.5	4.5	2.00
Test Statistic					13.5	1.32	0.188

We were not able to eliminate ant infestation of stacked hay bales by S. invicta. Of the six stacks of hay that we attempted to eliminate of ants foraging from colonies, we were only successful on two occasions. It seems unlikely that the colonies in these two cases simply left the stacks of hay considering that there was no colony absconding from control stacks. Bait applications in the field have been shown to provide roughly 90 percent suppression of ants when properly applied. In our case, colonies occupying unaffected stacks may have been killed by the bait while another colony took its place. We did not control for this in our experiment. There is a chance that ants in the stacked hay did not get a lethal amount of the bait into the colony due to resource competition for the bait with neighboring colonies in the area. There is also a chance that our results may have been improved if we were to have applied a broadcast application of the ant bait in the area in addition to the targeted application around our stacked hay. This may have reduced ant competition at our “ring” of bait around the base of stacks and may have reduced the potential for colony reinvasion by neighboring colonies. Given the difficulty in determining source areas for colony invasion in hay production systems, other areas for research may include protecting stacks of hay before an ant invasion occurs through the use of chemical barriers such as chlorpyrifos.

One important finding from this study is the presence of foraging worker ants attracted to hay bales on the second layer of stacked bales. The presence of live worker ants on regulated items constitutes an infestation according to USDA fire ant quarantine regulations and these second-layer bales would, therefore, be considered infested and not allowed to be transported outside of quarantined areas. The practice of allowing producers to move bales from untreated stacks not directly in contact with the ground (i.e., second layer and up), is therefore brought into question by these results.

Funding for this research was provided to Michael Heimer, County Extension Agent, Agriculture, Montgomery County, Texas through the Texas Department of Agriculture and the Texas Imported Fire Ant Research and Management Project. Thanks to Dr. White, and Mr. Berkeley, for hay and field sites. Thanks to Dr. Charles Barr for bait application support and equipment use.

Abstract. This research evaluated the efficacy of using a chemical barrier applied to the soil area under stacked bales of hay to prevent the red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae), from infesting stacked hay. Specifically, we were interested in determining if we could protect “clean” hay bales stored in fire ant infested fields for up to several weeks. Chemicals selected as barrier treatments were Lorsban® 4E, active ingredient chlorpyrifos, which kills ants on contact, and Astro™ Insecticide, active ingredient the pyrethroid permethrin, which can also act as a repellent to ants. We established a series of 12ft x 12ft plots, with a 10ft buffer between plots along a fence row in a fire ant infested field. Plots were grouped into four blocks of three stacks each. Plots within blocks were randomly assigned to each treatment (four plots treated with Lorsban® 4E and four treated with Astro™ Insecticide, and four control plots). Treatments included spraying a 12ftx12ft soil area with a 1-gal solution of each chemical and water formulation. After soil treatments, we placed four square-bales of hay, stacked two a side and interlocking in two layers, in the center of each plot. Stacked bales were sampled for fire ant infestation using 2.5 x 2.5cm olive oil –soaked index cards; one bait card was placed on each side of the top layer of hay in each stack. Results from ANOVA show a significant difference in mean infestation levels among treatments. Stacks of hay sitting in the chlorpyrifos plots had fewer ant infestations compared to the permethrin and control plots. Results after one week showed that only one stack in the permethrin, and two in the control plots were infested with ants, while none in the chlorpyrifos plots were infested. Results show that after three weeks all four control stacks, three stacks in the permethrin treatment, and two stacks in the chlorpyrifos plots were infested. These results indicate that on a short-term basis, such as 1 to 7 days, chlorpyrifos may be an effective short-term treatment option for protecting stacked hay from fire ant infestations.

The red imported fire ant, Solenopsis invicta Buren (Hymenoptera:Formicidae), frequently moves into or next to bales of hay that have been left in the field after harvesting and their mounds can interfere with the transportation of hay. The United States Department of Agriculture (USDA) has listed hay as a quarantined agricultural product. Currently, there are no USDA approved quarantine chemical treatments for assuring that S. invicta are not shipped to new locations. Hay bales that are not removed from fields immediately after baling and stored in an off-ground location cannot be shipped out of quarantined areas. Hay producers are in need of quarantine treatments that provide them reasonable options for the safe storage of hay before it can be shipped to other non-infested areas of the country. In the field, hay bales may provide a variety of microclimates such as thermoregulation sites, flood refuges, moisture under bales during drought, and the presence of both shady and sunny areas along the sides, which S. invicta, and other arthropods find appealing (Fig.1). Previous research, conducted by us, has shown that hay bales left in the field can become infested in untreated areas within a few days to weeks after baling (http://fireant.tamu.edu/research/arr/category/site/97-01pg42/97-01pg42.pdf). The objective of this study was to evaluate the efficacy of using targeted soil applications of Lorsban® 4E, active ingredient chlorpyrifos, and Astro™ Insecticide, active ingredient the pyrethroid permethrin, to protect stacked bales of hay from S. invicta infestation.

Research was conducted June 2002 in Montgomery County, Texas. Three treatments with four replicates of each treatment were used for a total of 12 sample units to compare S. invicta infestation levels on stacked bales of hay among treatments. Treatments were arranged randomly in four blocks (i.e., three stacks/block) along a fencerow in a fire ant infested field (Fig. 2). Treatments included: 1) control plots without chemical treatment, 2) 1-gal application of Lorsban® 4E12ft² (chlorpyrifos) area soil treatment, and 3) 1-gal application of Astro™ Insecticide (permethrin) 12ft²area soil treatment. Four bales of hay were stacked in the center of each plot. Insecticide applications followed printed label directions (4.73 ml Lorsban® 4E per 3.78 liter water; 2.36ml Astro™ Insecticide per 3.78 liter water).

Stacks of hay were sampled for ant infestation thorough visual inspection of stacks for ant mound building and using 2.5 x 2.5cm index (bait) cards soaked with olive oil pinned on the sides of the top (second) layer of hay in each stack. All bait cards were placed on hay bales under good S. invicta foraging temperatures (25°-30° C). Ant sampling was conducted for 45 min for one day each week for three consecutive weeks (June, 2002). We used analysis of variance (ANOVA) to test the hypothesis that our targeted bait applications around stacks of hay would significantly reduce or eliminate infested bales in treated compared to untreated stacks. We did not have enough degrees of freedom to do a repeated measures test with time of sampling as a treatment effect. However, we able to test whether there was an overall effect among the treatments by summing across the sampling periods, (JMP SAS, Cary N.C.). Significant differences among the means were determined using Tukey-Kramer honest significant difference (HSD) method (JMP statistics).

There was a significant treatment effect (Table 1). Stacks of hay in the Lorsban® 4E (chlorpyrifos) plots had significantly fewer mean occurrences (mean = 1.00) of ant infestation compared to stacks in the Astro™ Insecticide (permethrin) treated (mean = 2.00) or control plots (mean = 3.66) during the three-week sampling period (Tukey’s HSD = 0.46).

Examination of the timing of infestation show that after one week of chemical application only one stack in the permethrin, and two in the control plots were infested with ants, while zero in the chlorpyrifos plots were infested (Table 2). Results after three weeks show that all four control stacks, three stacks in the permethrin treatment, and two stacks in the chlorpyrifos plots were infested. These results indicate that on a short-term basis, such as 1 to 7 days, chlorpyrifos may be an effective short-term treatment option for protecting stacked hay from fire ant infestations.

Table 1. Results of analysis of variance (ANOVA) test comparing the mean number of hay bale stacks, per treatment, infested with red imported fire ants after three weeks in plots where either Lorsban® 4E(chlorpyrifos) or Astro™ Insecticide (permethrin) were applied to the soil under treatment stacks; N = 12 stacks of hay sampled with four treated with chlorpyrifos, four treated with permethrin, and four untreated control stacks. Ants were sampled with oil-soaked bait cards for 45-minutes on the second tier of hay in each stack.
Source	df	Sum of Squares	Mean Square	F-ratio	P >\|F\|
Treatment	2	10.888	5.444	7.000	0.027
Error	6	4.666	0.777
C. Total	8	15.555

Table 2. Number of stacks of hay infested with S. invicta and the number days until infestation. Hay infestation evaluation was conducted three weeks after plots where treated with either Lorsban® 4E (chlorpyrifos) or Astro™ Insecticide (permethrin) to the soil under treatment stacks; N = 12 stacks of hay sampled, with four treated with chlorpyrifos, four treated with permethrin, and four untreated control stacks. Ants were sampled with oil-soaked bait cards for 45-minutes on the second tier of hay in each stack.
Treatment	Sampling Period
	7 days	14 days	21 days
Control	2/4	4/4	4/4
Lorsban4E®	0/4	1/4	2/4
Pyrmethrin®	1/4	2/4	3/4

Ants quickly infested all of the unprotected hay bales. Yet, we were able to prevent ant infestation of stacked hay bales for a one-week period in the Lorsban® 4E (chlorpyrifos) soil treatment plots. We were not able to get the same level of protection using the Astro™ Insecticide (permethrin) treatments as we did with the chlorpyrifos treatment. Considering the high number of infested hay stacks and the relatively fast invasion rate of ants in the permethrin treated plots compared to the chlorpyrifos plots it appears that our pyrethroid barrier was not a suitable barrier in our situation.

Our initial results using the chlorpyrifos soil treatment may provide hay producers a small (e.g. 7 day) window in which hay destined for travel outside of a quarantined county can be stored on the ground before shipment. However, our results with this application of chlorpyrifos were not as long-lived as expected. In previous studies using chlorpyrifos sensitive quarantine regulated articles were protected from fire ant infestation for up to 6 weeks (http://fireant.tamu.edu/research/arr/category/site/97-01pg39/97-01pg39.pdf). In our study, ants were able to breach this protective barrier within a few weeks. It is unlikely that the active ingredient had degraded enough to allow ants to cross it. One possible explanation for the short period of protection afforded by treatments, based on limited observation data, may lie in the fact that some ant colonies may have occurred underneath or near the stacks of bales deeper in the soil than what was treated with the soil surface spray of the contact insecticides. After a short time (> 7 days) foraging ants tunneling up from these colonies may have been able to “cover-up” the chemical through excavation of uncontaminated dirt from deep within their colonies, thereby avoiding contact with treated soil particles and insecticide residues. Results suggest the need for another experiment where, larger areas in and around areas designated as hay storage locations may be selected for broadcast applications, to reduce ant populations, in addition to targeted application of chemically treated barriers.

Funding for this research was provided to Michael Heimer, County Extension Agent, Agriculture, Montgomery County, Texas through the Texas Department of Agriculture and the Texas Imported Fire Ant Research and Management Project. Thanks to Mr. Berkeley, for hay and field sites and to Mr. Kyle Miller at American Cyanamid for the Amdro® donation. Thanks to Dr. Charles Barr for bait application support and equipment use.

GEOTACTIC BEHAVIOR OF FEMALE ALATES OF RED IMPORTED FIRE ANTS ON QUARANTINE REGULATED ARTICLES

Abstract. This research evaluated geotactic (i.e., gravity-induced movement) behavior of queen (i.e. winged females called alates) the red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae), and methods to prevent flight queens from moving from a structure such as bee equipment representing a regulated article to the ground surface. For this study, we used commercial beekeeping equipment typically used in pollination production systems, but without bees. We evaluated queen geotactic behavior and mortality after placing them on top of bee equipment supported with insecticide treated pallets. All trials were completed in prefabricated (5 by 5 ft) ant enclosures (i.e., children swimming pools). Two barrier treatments were evaluated: 1) a support pallet treated with Lorsban® 4E (chlorpyrifos) under a beehive with no bees, 2) a support pallet treated with Astro™ Insecticide (permethrin) under a beehive with no bees. The untreated control treatment comprised bee equipment under an untreated support pallet. Queen movement and mortality were scored as the number of dead queens found on the equipment above the support pallet and the number of queens found below the support pallet. We used a wetted cardboard sheet to collect queens that crossed support pallets. Results show that 46% of the queens were found below the support pallet compared to 13% above support pallets. However, 41% of queens were unaccounted for in the ant enclosures. Of the queens found below treated pallets, significantly more were dead than queens found below untreated support pallets (df = 2,9, F = 10.44, P > 0.004). Result show that queens have a strong geotactic drive to migrate off of bee equipment and migrate towards the gound. Chemical barriers may not repel or overcome queen geotactic behavior. However, they were effective in killing most, but not all, queens that cross them within 24 hrs.

The red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae), reproduces by swarming during mating or nuptial flights. On warm, sunny mornings after a rain shower, winged males and females emerge from their colony nests or mounds and fly up into the air to mate. Newly mated queens orient back to the ground (geotaxis), break off their wings, and find or make a burrow in which to start their own colonies.

This fire ant swarming behavior and interstate commerce create serious risks for the potential spread of this invasive species. Newly mated queens can land on transportation vehicles carrying quarantine articles (such as nursery stock, sod, hay and bee hives) and other articles such as shrink-wrapped shingles or pipes on pallets and “hitchhike” to new, non-infested areas. Once at the new location, pallets are removed from trucks and placed on the ground. Newly mated queen ants surviving the trip can migrate to the ground at the destination and establish new colonies. These queen ants remain hidden and do not respond to bait-based survey methods or treatments.

The objective of this research was to evaluate geotactic (i.e., gravity-induced movement) behavior of female alate S. invicta (i.e., newly mated queen ants) and methods to prevent flight queens from moving from quarantine regulated articles (i.e., bee equipment) to the ground surface. Specifically, we evaluated the efficacy of candidate contact insecticides applied to a support pallet to prevent (repel) or kill S. invicta queens crossing treated pallets.

Experimental units comprised six ant enclosures containing a typical commercial beekeeping set-up (i.e., hive box with lid and support pallet) (Fig. 1). Hive boxes were newly reconditioned, cleaned, and painted and placed upon pallets. No bees were used for these experiments. We used two replicates of each treatment twice over time for a total of 4 replications for each treatment. We evaluated two barrier insecticide treatments: 1) a support pallet treated with Lorsban® 4E (chlorpyrifos) under a beehive, 2) a support pallet treated with Astro™ Insecticide (permethrin) under a beehive. The third treatment was an untreated controls comprised an untreated support pallet under a beehive. We placed a sheet of wet cardboard in the bottom of the swimming pools to attract and collect queens. This was intended to create a dark, moist, desirable habitat and refuge for queens, to evaluate the barriers’ repellent properties and/or assess queen mortality. Twenty-five queens (with clipped wings) were placed on the lid of the bee equipment (n = 300 queens total). After 24hrs, all parts of the bee equipment, cardboard, and pools were thoroughly searched for queens. The number of alive and dead queens on bee equipment, and below the support pallet (i.e. in the pools or cardboard) was scored.

We used analysis of variance (ANOVA) to test the hypothesis that our treated support pallets would reduce numbers of surviving queen ants crossing the treated pallet compared to untreated stacks, (JMP SAS, Cary N.C.). Significant differences among the means were determined using Tukey-Kramer honest significant difference (HSD) method (JMP statistics).

Queens had a strong behavioral drive to move off of the bee equipment. Results of queen movement after 24 hours shows that 46% of the queens were found below the support pallet compared to 13% above support pallets. Nearly half of the queens (41%) were unaccounted for in the study. It is possible that some queens may have been preyed upon by a bird observed frequenting the area. Some queens may have “jumped” or flown off the bee equipment and drifted out of the enclosure, while others were well hidden and overlooked.

The mean number of queens found dead below treated support pallets was significantly more than the number dead under untreated support pallets (Tukey’s HSD = 3.4)(Table 1): Lorsban® 4E (chlorpyrifos) mean killed = 9.75; Astro™ Insecticide (permethrin) mean kill = 11.25; and, untreated control mean kill = 1.25. Queen ants that had crossed insecticide-treated pallets that were still alive after the end of the initial 24 hr trial period appeared to be affected and were all found dead a following another 24 hr period.

Contact insecticide barriers may not repel or overcome queen geotactic behavior. However, they were effective in killing most, but not all, queens that cross them within 24 hrs. Ant swarming behavior usually occurs in early spring or early fall, which may provide a window in which treatments of this type may best be used to target queens that may be transported on trucks and articles originating from S. invicta quarantine areas. An alternative to treated pallets or additional safeguard (wider treated buffer zone) to prevent introduction of newly mated queens from transported articles can include a soil/ground surface application of a contact insecticide where pallets are to be placed at the destination, particularly during times of years that winged reproductive ants are known to swarm. Spot treatments should be applied before moving quarantine-regulated item into non-quarantined site. Conceivably, a soil drench would be more affective in killing queens than a pallet application due to increased treated surface area and exposure potential associated with the soil treatment

Table 1. Results of analysis of variance (ANOVA) test comparing the mean number of dead queens, per treatment, found below treated and untreated support pallets. Two barrier treatments were evaluated: 1) a support pallet treated with Lorsban® 4E (chlorpyrifos) under a beehive; 2) a support pallet treated with Astro™ Insecticide) under a beehive. Untreated controls comprised of an untreated support pallet under a beehive.
Source	df	Sum of Squares	Mean Square	F-ratio	P >\|F\|
Treatment	2	232.66	116.33	10.44	0.0045
Error	9	100.25	11.40
C. Total	11	332.91

We thank Paul Jackson for bee equipment procurement and Charlotte Lorbieski (Weeks’s landlord) for field site use. Funds for this project were provided to John G. Thomas, Executive Secretary Texas Beekeepers Association thorough the Texas Department of Agriculture and the Texas Imported Fire Ant Research and Management Project.

1) Beekeeper evaluations of broadcast applications of fire ant baits in honey bee operations

The red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae), among other pest ant species (e.g., Argentine ants, Linepithema humile Mayr) can invade honey bee, Apis mellifera L. (Hymenoptera: Apidae), colonies and feed on pollen and developing bees (Buys 1990, De Jong 1990, Taber 1994). Weak bee colonies are more susceptible to ant invasions than healthy, vigorous colonies. Often, fire ants build their nests directly against, under, or on apiary equipment. Several ant species, as well as S. invicta, may use apiary equipment for colony thermoregulation, as refuges to escape localized flooding events, and to take advantage of better nesting conditions during dry conditions (Burrill 1926). No insecticides have been registered specifically for treating apiary equipment to eliminate S. invicta. However, several products on the market are labeled for S. invicta under a variety of conditions. For example, Amdro® (hydramethylnon) is an approved bait applied insecticide for control of S. invicta that can be applied in turfgrass and pastureland on which bee hives are often located. The objective of this study was to solicit the responses of beekeepers to the use and results of broadcast bait applications of Amdro® in their bee yards.

At the Texas Beekeepers Association in Kerrville Texas 2000, four beekeepers volunteered to apply and evaluate the broadcast bait application of Amdro® in their bee yards. In May 2001, each beekeeper was mailed a handheld seeder and a 1-lb. package of Amdro® (hydramethylnon), and an instruction sheet on how, when, and where to apply the bait. Three basic steps were used to document the effectiveness of the bait product in their apiaries: 1) estimate and record the number of active fire ant mounds in one to three 1/8-1/4 acre areas within each treated and untreated areas prior to bait applications; 2) apply ant bait product (when ants were actively foraging) with hand seeder to one half of each field; 3) record fire ant related honey bee problems; and, 4) take new estimates of active ant mounds in both treated and untreated areas after 5-7 weeks. Beekeepers were asked to complete a questionnaire to document their experience and perceptions about the broadcast bait results. Specifically, beekeepers were asked the following questions:

• Did the beekeeper observe any mortality of bees due to the Amdro® treatment?

• Do fire ants cause problems in their beekeeping operations, and were these problems reduced by the bait treatment (i.e., could this treatment have a positive impact)?

• Were results of this treatment better than previous control efforts; easier to apply, etc.?

Three of the four beekeepers returned completed questionnaires. Of these, all three where satisfied with the broadcast bait results and stated that Amdro® treatments provided adequate control of fire ants. No beekeepers observed any bee mortality caused by the ant bait applications. All three beekeepers thought that the broadcast bait applications were easier and more effective than previous methods (e.g., diazinon granules placed on individual ant mounds).

We developed a kit to sample for fire ants on flat bed and tractor-trailer rigs carrying agricultural items originating from fire ant infested areas. We asked four volunteer beekeepers to evaluate the kits use and effectiveness in capturing ants on trucks. We mailed beekeepers "kits" containing pre-cut bait cards, 20ml of olive oil bait, collection tubes, and return postage for the kits after use. We intended to collect used kits from beekeepers for ant identification. Truck sampling consisted of three basic steps: 1) Placement of several (5-6) bait stations in secure areas on the bed of the truck/trailer during transportation; 2) Cap and collect baits at the destination site; 3) After several (4-5) trucks were sampled, the collection kits were to be mailed back to us for ant identification. This effort addressed several goals. First, by developing an easy and efficient method for sampling for ants in bee equipment being transported, beekeepers could gain improved knowledge of potential fire ant problems (i.e., ant infestations in their bee hive shipment) instead of being surprised at state border crossing stations. Secondly, data of this type will help determine the effectiveness of current certification methods (i.e., compliance agreement developed by the Texas Department of Agriculture and procedures developed by other regulatory agencies) aimed at ensuring fire ant-free honey bee shipments.

We have received two ant kits. However, no ants were collected. Currently, we are working on a less expensive sampling kit and conducting additional evaluations.

Funds for this project were provided to John G. Thomas, Executive Secretary Texas Beekeepers Association thorough the Texas Department of Agriculture and the Texas Imported Fire Ant Research and Management Project.

Abstract. The Texas Department of Transportation provided funding to the Texas Fire Ant Project to develop a prototype bait applicator device capable of treating right-of-way and rest stop areas. Dr. Charles Coble, Agricultural Engineer at Texas A&M University has developed a truck-mounted “bait blower” (Figure 1) that uses a two-cycle gasoline engine to power a industrial-size blower. Bait is metered into the air blast using an auger calibrated to apply the material at the proper rate and can be adjusted for driving at different speeds. It has been demonstrated to apply 0.45 to 0.675 kg (1 to 1.5 lbs) of a bait-formulated fire ant control product while driving at 40 km (30 mi) per hour. Swath width varies with wind direction, but ranges from 900 to 1500 cm (30 to 50 ft). At a speed on 16 km (10 mi) per hour, the device can apply bait at a rate of 0.4 ha (1 acre) per minute, as demonstrated in fall of 2000 when 20 ha (50 acres) of Magnolia Gardens Nursery in Montgomery County, Texas, was treated within two hours. This device could be useful for applying bait products in community-wide imported fire ant management programs, abatement districts, attempted spot eradication programs.

Figure 1. Prototype truck-mounted “bait blower” developed by Dr. Charlie Coble with funding from the Texas Department of Transportation.

As partial fulfillment of a grant from the Texas Department of Transportation to develop methods for quickly treating roadsides and rest stops for red imported fire ants, Solenopsis invicta Buren (Hymenoptera: Formicidae), the Department of Agricultural Engineering was subcontracted to develop a bait blower prototype capable of applying 1 to 1.5 lbs. fire ant bait insecticide products at speeds up to 30 miles per hour. Charles Coble designed and developed the prototype illustrated in Fig. 1 and depicted in Fig. 2.

The hopper (Huskee 235) is capable of holding about 25 lbs. bait-formulated insecticide. It is metered at the bottom of the funnel-shaped hopper using an auger similar to that described by Williams et al. (1983). The material then falls through a small plastic funnel into the airstream produced by a “squirrel-cage” type fan or blower (AF-15 American Fan Co., Fairfield, OH). The blower is powered by a gasoline engine (Vanguard 16 HP V-Twin, Briggs & Stratton®) linked by a fan belt. The power train also connects to a variable-speed clutch that can adjust the speed of the fan belt to the auger for calibration.

On September 8, 2000, with the assistance of Dr. Brian W. Shaw, Extension Agricultural Engineering Specialist, we positioned 9 5 ft-diameter children’s plastic swimming pools in a row beginning 3 ft from the truck-mounted prototype bait blower, which was positioned 5 ft. 4 in. to 6 ft. 2 in. above the ground. We ran the bait blower for 4 minutes and then collected and weighed the fire ant bait collected in each swimming pool. This procedure was repeated with wind across the line of pools and facing the wind. Pools collected 596 g. bait facing cross-wind, 344 g upwind and 810 downwind. A lot of bait failed to be collected in the pools during the cross-wing procedure. Distribution of bait collected was plotted for each run (Fig. 3) Swath width varied from 25 to 50 ft (Fig. 4), with most of the bait being collected in a swath approximately 10 to 20 ft from the side of the truck depending on orientation to the wind. The prototype emitted 2 lbs. bait product per minute. Calibration settings were determined for applying 1.5 lbs. Bait at 10, 30 and 45 mph (variable clutch handle fully back, 10 rotations/2.7 sec. And fully forward, respectively).

Figure 4. Distribution patterns of fire ant bait applied by a truck-mounted prototype fire ant bait broadcast applicator under various orientations with the wind (upwind having the smallest distribution and downwind having the farthest distribution) .

On October 18, 2000, the bait-blower prototype was used to demonstrate tratment fo Magnolia Gardens in Montgomery County, Texas (Chris Fox, Production Manager) using Distance® (pyriproxyfen) Fire Ant Bait donated by Valent U.S.A (Bill Sewell, bsewe@valent.com). The 50-acre containerized nursery was treated using 1.5 lbs. product at a speed on 10 mph at a rate of 1 acre per minute. In that operation, blocks of containerized plants are in in two 45 ft.-wide strips between gravel roadways, separated in the middle by a drainage strip. Along the road, walkways are provided into the strips every 6 to 7 ft. Distribution into the blocks of plants was acceptable.

The device was demonstrated again, October 2, 2001, at Greenleaf Nursery near El Campo, TX (Elec Ruiz, Pest Management Coordinator) with the assistance of Rody Best (Extension Associate), Daniel Fromme (Extension Agent - IPM, Wharton Co.) And Dr. Carlos Bogran, Assistant Professor and Extension Entomologist.

The currently available truck-mountable broadcast fire ant bait spreader, the Herd Model GT-77 (Herd Seeder Company, Inc., P.O. Box 448, Logansport, Indiana 46947-0448; 219/753-6311) is only capable of applying a swath (30 ft wide) from the back of the vehicle. The swath covers both sides and back of the vehicle, so when applying the material from a roadway, much of the material lands on the road. Speed of the vehicle determines, in part, the rate at which bait products are applied and is usually restricted to speeds of less than 10 miles per hour.

The prototype bait blower described herein and demonstrated can provide broadcast application in situations like roadways, roadside parks, containerized nurseries and neighborhoods where application is made from roadways. It applies the swath to one side of the vehicle at speeds of up to 30 miles per hour. It should be of interest to commercial application of fire ant bait products to larger areas such as in communities, commercial nurseries and tree farms and highway and park maintenance operations.

Williams, D. F., C. S. Lofgren, J. K. Plumley and D. M. Hicks. 1983. Auger-Applicator for Applying Small Amounts of Granular Pesticides. J. Econ. Entomol. 76(2)395-397.

The mound-building and foraging characteristics of the red imported fire ant, Solenopsis invicta Buren (Hymenoptera: Formicidae) usually depend heavily upon environmental conditions. Plentiful rainfall and mild temperatures can create favorable environmental conditions which allow an increase in mound-building and foraging activity, as well as encourages the development of fire ants and increase the presence of winged reproductive in the mounds. During unfavorable weather conditions (extreme hot or cold, wet or dry periods), fire ants typically exhibit very little mound-building and foraging activity.

In January of 2000, the Red Imported Fire Ant Activity and Weather Reporting Program was initiated to further examine the correlation between environmental conditions and fire ant activity. It was hoped that information obtained from this program would allow interested individuals to gain a better understanding of the fire ant activity in relation to the temperature, precipitation, soil type, etc. in their region. The results would also allow researchers to better understand the current and historical activity state of fire ant colonies, the probable occurrence of mating flights, and the relative ant mound numbers through the years.

One permanent, untreated site was selected in each major urban area of the state: Dallas/Fort Worth, Bryan/College Station, Austin, Houston, and San Antonio. The location and characteristics for each site were described and photographed (see below).

The monitoring location is characterized by native grasses in varying degrees of density from 30 to 100% coverage. There are also very small mesquite trees in the monitoring plot with limited growth due to quarterly mowing by maintenance personnel. There is no shade except that provided by taller grass growth and what the small mesquites might produce. Soil type is black clayey soil with low to moderate moisture in the upper strata. During extended hot and dry weather periods, the soil in the monitoring area develops very impressive cracks of varying width from very narrow up to ~2 inches (see below).

The field is vacant and very flat with several low spots. The vegetation primarily consists of Johnson grass and is mowed periodically. There are no trees, and very little other vegetation.

This site is located approximately 15 miles north west of down town Fort Worth and is directly off of a major thoroughfare. Of the two acres used for this site one acre is vacant while the other has a greenhouse located on the premises. Very few trees other than a few small red buds to the east and one large bois d'arc to the north. Other plant material included knotweed, clover, and field thistle. The site is mowed regularly and appears to have been quite disturbed in past years. Tire ruts on the west side are apparently from the adjacent road and high traffic volume.

The site is located on the Texas A&M Riverside campus about a mile from the Brazos River. Topography is nearly flat with some natural undulations due to the soil's high shrink-swell properties. Soil is an upland fine sandy loam over claypan in the Post Oak Savannah range site. The site floods to a depth of a few inches during heavy rains, but drains within a day or two. The sandy surface layer dries quickly during the summer, becoming quite hard due to the clay sub-soil. Vegetation consists of native grasses, primarily Bahia, King Ranch Bluestem and Bermuda, with a nearly solid cover. The area is mowed frequently, but has remained otherwise undisturbed for many years.

Because of susceptibility to periodic flooding, a new site was established in January of 2001. The new site is approximately 200 yards to the south of the original site, on the Texas A&M Riverside campus. Soil conditions are similar to the original site- sandy loam over claypan; however, the new site is slightly sloping towards a large pond approximately 35 yards away. Periodic flooding should not be a factor due to the fact that the site has a gently slope to it. Similar to the original site, the vegetation consists of native grasses, primarily Bahia, King Ranch Bluestem and Bermuda, with a nearly solid cover. The area is mowed frequently, but has remained otherwise undisturbed for many years.

On or around the 10^th day of each month, beginning in January of 2001, Texas Cooperative Extension personnel in the five major urban areas evaluated their site for fire ant mounds, estimated fire ant numbers and noted brood type.

Austin: Lisa Lennon, Travis/Williamson County Extension Agent- IPM (Fire Ants)

Houston: Dr. Paul R. Nester, Harris County Extension Agent-IPM (Fire Ants)
Dallas/Fort Worth: Beth Hickman, Dallas/Tarrant County Extension Agent-IPM (Fire Ants)

Site selection and description: Efforts were made to select a regularly mowed area or a moderately grazed area. Irrigated sites were avoided (they were not indicative of natural environmental conditions). Plots were marked with a permanent structure such as re-bar or ground plates. Physical location of the site was recorded and the site conditions (i.e., turfgrass, pasture, roadside, athletic field, etc.) were described/characterized, as well as any other factors that might influence imported fire ant populations (proximity of water, soil type, etc.). The temperature and rainfall information for each site was obtained monthly via the Office of the Texas State Climatologist web site (http://www.met.tamu.edu/met/osc/).

Monitoring plots: A 1/4 acre circle (58 ft radius) was established for monitoring mound numbers and condition during each evaluation. The total number of mounds within the 1/4-acre circle were counted, and the mound diameter (inches) and condition (1 = Dormant or flat (no sign of fire ant worked soil on surface); 2 = intermediate; 3 = freshly built, fluffy (fine, worked soil particles on surface) was recorded.

Another six-foot wide 'transect' plot was established for evaluating brood numbers and condition. Each active ant mound encountered from the beginning of the transect, regardless of size/condition, was shoveled into and examined until a total of 15 mounds (if possible) had been sampled. Mound diameter (inches) was measured and given a value: 1 = tiny (<2") ant mound; 2 = small (2-5"); 3 = medium (5-10"); 4 = large (10-15"); 5 = very large (>15"). The number of brood (0 = none; 1 = some; 2 = more; 3 = a lot or brood (larvae and pupae)) was recorded, as well as the type of brood observed (n = none; w = worker larvae/pupa; r1 = few; r2 = some, r3 = many reproductive larvae/pupae; a = presence of winged reproductive ants). The length of the transect plot length was also recorded. If room allowed, re-sampling transect plots was avoided on subsequent visits.

The temperature was recorded and the date and time of the evaluation, as well as any other pertinent information (weather conditions, soil moisture, vegetative cover). Data was entered into a Microsoft Excel spreadsheet (see appendix) by each evaluator and then sent to Rody Best, Extension Assistant, for processing and posting.

Results from each site were reported monthly on the web site, http://fireant.tamu.edu. The information generated through these efforts can be both interesting and useful in making correlations and comparisons between months, years and sites (Figures 1 & 2). Fire ants in nearby sites may have different developmental and health conditions than those in the permanent monitoring plots, therefore; the individuals managing imported fire ant populations are encouraged to verify observations reported with the activity of ant populations in their management area.

Information generated through these efforts provides data for further analysis. However, they illustrate the importance of local environmental factors on imported fire ant biology. Production of reproductive brood and presence of winged reproductives (alates) in fire ant mounds signals preparation of mating (nuptual flights) in local areas, which is useful to understand re-invasion of fire ants into previously treated areas.(Table 1). Production of winger reproductive occurs mainly in the spring and fall, or during periods of favorable conditions. However, mating flights are triggered by rain events occurring at any time of the year when alates are present in mounds.

Table 1. Percent fire ant mounds with reproductive brood/alate (winged) adults, 2001.

Information generated through this effort will increase in value over time as new information is generated to develop improved simulation models for describing the dynamics of fire ant colony caste development and mound-building activities. It is also useful to describe ant activity during seasonal environmental conditions that may be useful in determining why certain management efforts were successful or not. Since 1997, for instance, summer drought conditions throughout much of the state have reduced the success of phorid fly releases and helped reduce the need for fire ant insecticide applications.

We would like to thank the following people for their assistance with this project:

Nathan L. Riggs, Extension Agent- IPM (Fire Ants) Bexar County
Lisa Lennon, Extension Agent- IPM (Fire Ants) Travis/Williamson Counties

Figure 1. Summary statistics for Bryan weather and fire ant reporting site # 1 (top) and Bexar County site, 2001.

Figure 1. Daily mean maximum and minimum temperatures and daily mean precipitation, College Station, TX

Figure 2. Summary statistics for Bryan weather and fire ant reporting site # 1 (top) and #2, 2002.

Summary: In 2001 the total annual household expenditure for single-family residences to treat fire ants in the Fort Worth area was over $72 million. The majority of that expense comes from treatments (chemical insecticides) used to control fire ants. When this community-wide fire ant management program was first initiated in 1999 not only was expense a problem, but, the chemicals were being over-used and becoming a major source of surface water contamination.

Problem: The program that was first initiated in 1999, but had ceased to exist. Mr. Scott Curtis had noticed an increase in fire ant populations as well as an increase in chemicals being used by the residents to control them. In order to avoid the exuberant fire ant populations seen at Lakeview Country Estates prior to 1999 the Community-Wide Fire Ant Management program was reinstated.

Objective: To train homeowners in the proper use of bait-formulated insecticides and teach them to work together to control fire ants. By doing so neighbors of Lakeview Country Estates may be able to reduce their costs of fire ant control as well as decreasing the chance for re-infestations.

One week prior to the designated Community-Wide fire ant treatment day the neighborhood ant population was sampled. Results of this survey are found in Table 1. Plastic condiment dishes were filled with beef hotdog in order to attract the ants. On the first weekend in June forty-three residents turned out to participate. Each resident was given enough Amdro® (hydramethylnon) to treat their front yards. Residents were then loaned a hand-held seed spreader preset to the lowest opening. The rate of Amdro applied to each yard was one pound per acre. Residents that were not able to participate made arrangements to have their yards treated by those who were in attendance. So in theory this treatment day had one hundred percent participation.

Five months after the community-wide treatment day bait cups were once more placed in twenty-five yards of residents of Lakeview Country Estates. The results of this survey can be seen in Table 2. After five months the results were evident. The populations of fire ants had decreased while the populations of native (competitor) ants had increased. Post surveys were compiled and showed that homeowners had been using less chemicals to maintain low fire ant populations.

Economic Analysis and Impact: Fire ant control in residential areas can be costly and detrimental to the environment. With entire communities working together chemical costs can be greatly reduced as well as the amount of chemicals used.

Conclusion: Fire ants can be managed with less chemicals and less expenditures when communities work together. The residents of Lakeview County estates are convinced of the benefits of holding a community-wide fire ant treatment day and already have plans to continue this project.

Lakeview Country Estates Pre-treatment Counts Ant Population 1-Jun-2001	Lakeview Country Estates Post-treatment Ant Populations 15-Oct-2001
1. no ants	no ants
2. Pheidole dentata	Pheidole dentata
3. Pheidole dentata	no ants
4. Pheidole dentata	no ants
5. Solenopsis invicta	no ants
6. Solenopsis invicta	no ants
7. Tetramorium bicarinata	Pheidole dentata
8. Solenopsis invicta	no ants
9. no ants	no ants
10. Monomorium minimum	no ants
11. Solenopsis invicta	no ants
12. Monomorium minimum	no ants
13. Solenopsis invicta	no ants
14. Solenopsis invicta	no ants
15. Solenopsis invicta	no ants
16. Solenopsis invicta	no ants
17. Pheidole dentata	Monomorium minimum
Table One	Table two
18. Solenopsis invicta	Solenopsis invicta
19. dog ate the bait cup	no ants
20. Solenopsis invicta	no ants
21. no ants	no ants
22. no ants	no ants
23. Solenopsis invicta	no ants
24. Solenopsis invicta	no ant
25. Solenopsis invicta	no ants
26. Pheidole dentata	no ants
27. Solenopsis invicta	no ants
Total Fire Ants: 14	1
Total Other Ants: 8	3
Cups with no ants: 5	21

The site for this test was selected in the formal gardens at Kiest Park, southwest of downtown Dallas. Students identified and marked off each individual ant mound in the test site. Each mound was then mapped and digitized as to its location, relative to surrounding features in the site. Mounds were then treated with Amdro Fire Ant Bait (0.73% hydramethylnon) and after a period of time mound sites and ant populations were recorded again. The students were able to take the data from this test and create G.P.S. based maps showing ant intensities, and movement throughout the test site project allowed the students of Bishop Dunne High School to apply their computer skills to a very real problem facing the residents of Dallas.

Problem: Mr. Brad Baker and his High School G.P.S. course (8^th grade -12^th grade) needed a way to incorporate the knowledge they had gained in their G.P.S. course, and the Texas Red Imported Fire Ant Project needed a way to map out the spatial dynamics of fireant:native ant interactions.

Objective: To map out the specified area of Keist Park and observe the Fire Ant activity in said region.

The site was mapped out and or/digitized, including the locations of man-made features, locations of trees, and shrubs. Prior to treatment, these areas were surveyed by the students of Bishop Dunne High School for active fire ant mounds and then their locations were plotted using the G.P.S. system. Ten permanent sample sites were established for the purpose of monitoring forage ants. The sites were designated with nails and paint to ensure there permanence. Foraging ants were sampled and monitored using baited condiment cups. One bait cup was placed at each sample site. The bait cups contained a proteinaceous/fatty bait such as Vienna sausages. Bait cups were left open for ½ to one hour, depending on recruitment pressure, then capped and frozen for later identification.

Evaluations (both mound counts and bait cups) took place immediately prior to treatment and several weeks post treatment. Treatment was made using Amdro® Fire Ant Bait (0.73% hydramethylnon) applied at 1.5 lbs./acre using a hand-held broadcast spreader on 1-May-01.

The ten permanent sample sites were monitored and bait cups were placed out 4 days after the initial treatments. After the first surveys were completed, the ten transects were reduced to eight. This was done in order to add the students in the arrangement of their maps. Results of the surveys are detailed in Table 1, 2 and 3. Unfortunately, there were no native ants found in the treated areas. However, in the untreated areas the tables show the pressure which the fire ants place on the native ants. Fire ants that were present in the treated area were significantly reduced. The G.P.S. maps created by the Bishop Dunne High School students that detail the positions of the mounds, and the mound densities are under the headings Figures 1, 2 and 3. To view the graphs created by the students of Bishop Dunne High School in full color go to the fire ant web site: fireant.tamu.edu.

Transect 1

Transect

1	x	x	x	x	x	x	pd	mm	x	si
2	x	x	x	x	si	x	ts	mp	si	dp
3	x	x	x	x	x	ts	pd	pi	si	pi
4	x	x	x	x	x	x	c	si	x	dp
5	x	x	x	x	x	/	/	/	/	/

bait cup

Transect T1

Transect

1	X	X	X	X	si	si	si	dp	mm
2	X	X	X	X	si	si	dp	mm	mm
3	X	X	X	X	si	si	dp	/	/
4	si	X	X	X	/	/	/	/	/

bait cup

Transect T1

Transect

1	X	X	X	X	si	si	si	dp	mm
2	X	X	X	X	si	si	dp	mm	mm
3	X	X	X	X	si	si	dp	/	/
4	si	X	X	X	/	/	/	/	/

Figure 3. Location of fire ant mounds as well as density of mounds in Keist Park.

Figure 1. Fire ant colony against stacked hay.	Figure 2. Twelve stacks of hay in Montgomery County, TX.

Figure 1. A large fire ant colony moved against stack of hay.	Figure 2. Stacks of hay in Montgomery County, TX.

1	x	x	x	x	x	x	pd	mm	x	si
2	x	x	x	x	si	x	ts	mp	si	dp
3	x	x	x	x	x	ts	pd	pi	si	pi
4	x	x	x	x	x	x	c	si	x	dp
5	x	x	x	x	x	/	/	/	/	/

1	x	x	x	x	x	x	pd	mm	x	si
2	x	x	x	x	si	x	ts	mp	si	dp
3	x	x	x	x	x	ts	pd	pi	si	pi
4	x	x	x	x	x	x	c	si	x	dp
5	x	x	x	x	x	/	/	/	/	/

1	x	x	x	x	x	x	pd	mm	x	si
2	x	x	x	x	si	x	ts	mp	si	dp
3	x	x	x	x	x	ts	pd	pi	si	pi
4	x	x	x	x	x	x	c	si	x	dp
5	x	x	x	x	x	/	/	/	/	/