Red imported fire ant insectides formulated as baits on light particles of processed corn cob grits coated with soybean oil, as is commonly used in the formulations of hydramethylnon (Amdro®), avermectin (Affirm®), fenoxycarb (Logic®) and Pro-DroneTM, are registered for broadcast application at a rate of 0.8 to 1.5 lbs formulated insecticide per acre. The methods used to achieve these low rates are no clear and difficulties exit in complying to the label directions with conventional application equipment. American Cyanamid Company had developed and distributed a bulletin in an attempt to assist individuals attempting to use their product (anonymous, 1980, AmdroR Fire Ant Insecticide Information Bulletin, "Application equipment information", PE-5824, American Cyanamid Company, Wayne, New Jersey).
Aerial application of fire ant baits requires special modifications
of application equipment, but most applicators are restricted to attempting
application with conventional seeding/granular fertilizer application equipment
and at most, turning the air scoop forward. This method demonstration was
conducted in cooperation with Henry P. O'Neal, Dr. Jack D. Price and Dr.
Rodney Holloway to determine the effectiveness of aerially applying Amdro
at the 1987 Brazoria County Aerial Application Clinic.
Materials and Methods
The cooperator in this method demonstration was pilot James Knape,
using an Ag Cat airplane fitted with a Stainless Steel Fabricators, Inc.
Spreader. The pilot was instructed to fly over a series of 1 meter square
funnels placed in a row 30 meters across the flight path. Granules collected
in the funnels were weighed and weights were entered into a computer program
that plotted the distribution pattern of the granules in the swath, and
produced a printout including other technical and environmental information.
The program was also capable of calculating optimum swath width based on
the data collected.
Tables 1 and 2
list the results of this method demonstration. On the day of this demonstration
(March 4, 1987, 2:06 pm), the temperature was 70oF and wind
was blowing at 12 mph. The pilot flew into the wind to make the trial application.
By adjusting the settings of the gate opening to 11.5 turns, the pilot
was able to achieve an application rate of 1.0 lbs per acre at a swath
width of 40 ft, flying at an altitude of 12 ft and at a ground speed of
96 mph. However, the range of material applied within this swath was from
0 to 2.5 lbs per acre. The simulated optimum swath width for applying 1.1
lb per acre of material was 52 feet. In this simulation, the range of rates
of bait applied within the swath was from 0.5 to 2.2 lbs per acre. The
rate range within the actual and simulated swaths illustrate the difficulty
of achieving a proper application of bait formulated fire ant insecticides
by air, and explains, in part, the erratic results of product efficacy
form trials in which these baits had been aerially applied.
1.) AIRCRAFT ID:AC N48655
PASS: 1-2
SPREADER: SSF
MATERIAL: AMDRO
VANE SPACINGS FOR SETTING # :
2.) GROUND SPEED: 96 MPH FLIGHT HEIGHT: 12 FT. OR 3.7 M
3.) WIND SPEED: 12 MPH
WIND DIRECTION (090= IN WIND): 116
TEMPERATURE: 70F, OR 21C
RELATIVE HUMIDITY: 31%
4.) NUMBER OF NONZERO WEIGHTS: 19
TOTAL RATE: 20.3KG/HA, OR 18.1 LB/AC
LATERAL DISPLACEMENT OF MASS:
0.65 M LEFT
VERTICAL CENTROID:
0.7 KG/HA, OR 0.6 LB/AC
MEAN RATE: 1.1 KG/HA,
OR 1.0 LB/AC
SWATH AT MEAN: 12.0 M, OR 39 FT
CALIBRATED SWATH WIDTH: 12.2 M,
OR 40 FT
MEAN AT SWATH: 1.7 KG/HA, OR 1.5 LB/AC
Table 2. Coefficient of variation vs
swath width racetrack lapping and racetrack lapping 16 meters or 52 feet
reports, documenting results of computerized simulation of the optimum
application pattern calculated from data obtained by aerially applying
hydramethylnon (AmdroR) fire ant bait insecticide, Brazoria
Co., Texas 1987.
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