Know Your Fire Ant Baits From The Contacts!

In the control of red imported fire ant infestations, there are primarily two types of weapons: bait formulated insecticides and contact insecticides. These products work differently and it is important to understand these differences in order to get the most benefit for the dollar spent.

Bait Formulated Insecticides: A bait insecticide combines an ant-attractive food source with an insecticide. These products are only effective for controlling fire ants when the ants feed on the bait and ingest the insecticide. Because ingestion is required for them to work, they are more specific for targeting ants.

There are two general ways in which bait products work: 1) direct toxicants, and 2) insect growth regulators or IGR's. Direct toxicants poison all stages of ants, including adults, while insect growth regulators cause the queen to lay infertile eggs or prevent the ant larvae from developing into worker ants. Insect growth regulators are slower acting than toxicants, with both types of bait products being slower to kill ant colonies than contact insecticides. Because of the slower rate of action, re-invasion by fire ants is considerably slower than with contact insecticides.

Bait formulations are best applied as a broadcast because the bait allows ants from all colonies in the treated area to collect the bait, rather than trying to locate individual mounds. Also, bait insecticides not collected by the ants rapidly decompose in the environment. Available baits used include Amdro®, Award® or Logic®, Ascend®, Extinguish® or Justice®, Spectracide® Fire Ant Bait, Eliminator® Fire Ant Bait.

Granular and Liquid Contact Insecticides: Products that are formulated to kill insects upon direct contact. Contact insecticides kill only those insects that come in direct contact with them, hence the name. These products come in different forms, including granules, dusts, powders, and liquids. Some of the more common insecticides include: Dursban® (recently withdrawn), diazinon, Orthene®, Talstar®, Rapid Kill®, Organic Solutions®, Citrex™ Fire Ant Killer, and others.

The formulation of contact insecticides does not attract ants to it, as do the baits. Instead, for these products to work, the dust or granules, or liquids have to be placed on top of the mound to come in "contact" with as many ants as possible. Dusts sift through the top of the mound and the ants that walk through the dust will carry it on their bodies and inside the colony. Granules must watered into the mound when directed by label so that the toxic ingredient is washed into the nest to contact the ants. Otherwise, the product just causes the ant colony to move to a new nesting site.

When the label instructions are not followed, the treatment may not kill the fire ant colony or, may cause the colony to split into more colonies.

Another tip for using contact insecticides is not to disturb the mound when applying individual mound treatments. Since only the ants coming in contact with the treatment are killed, the queen(s) is moved away from the disturbance, the treatment will be less likely to kill the queen and thus the colony.

Insecticide treatments do not prevent future fire ant infestations. Fire ants can rapidly re-invade the treated area from adjacent non-treated areas. Controlling the ants in cooperation with your neighbors reduces re-invasion pressure. Locating and treating individual fire ant nests can be difficult, particularly during hot and dry weather periods. When fire ant mound numbers exceed 5 mounds per 10,000 square feet, it is more economical and easier to broadcast a bait product.

Always make sure to read and follow label directions before applying.

For more information on fire ant management, contact your local County Extension office or 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 the Texas  Agricultural Extension Service or the Texas Agricultural Experiment Station is implied.

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

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