Effectiveness of EL-468, and Ac 217,300 for Control of Imported Fire Ants, 1980

Field tests were initiated in Hamilton Co, FL with EL-468 (Eli Lilly and Company), and AC 217,300 (American Cyanamid Company) formulated as bait toxicants for control of natural infestations of the red imported fire ant (RIFA). Baits were formulated in 30% soybean oil and 70% pregel defatted corn grits (PDCG). The AC 217,300 was formulated in a 25% soybean oil and 75% expanded corncob grit bait (ECG). The EL-468 baits formulation also contained 0.25% Calico oil blue dye in the soybean oil so that worker ants could be collected and examined for uptake of the bait. All applications were made using a tractor-mounted auger applicator. Fifty 1-acre plots were established in an improved pasture of bermuda grass Cynodon dactylon (L.) and each plot contained a 0.5-acre circular subplot for evaluation. The population index method (Harlan et al; 1981. Southwestern Entomol. 6: 150-157) was used for evaluation. Five 1-acre untreated plots were used as checks. Twenty-four hours following treatment with the EL-468 baits, 25 colonies in each treated plot were sampled to determine the percentage of ants that fed on the bait. Post-treatment evaluations were made at 6 and 30 wk. The reason that evaluations were not made at 12 and 18 wk post treatment was due to severe drought conditions occurring between the 6 and 30 wk post treatment periods. Under these conditions evaluations are not possible since the ants move deep underground, and thus, are not available for observation.