Field Evaluations of Broadcast and Individual Mound Treatment for Red Imported Fire Ant, Solenopsis invicta Buren, (Hymenoptera; Formicidae) Control in Virginia, USA

Field evaluations were conducted to determine efficacy, residual activity, and knockdown potential for fire ant control products. Broadcast granular products (Advion, 0.045% indoxacarb; and Top Choice Insecticide, 0.0143% fipronil) were individually evaluated, and compared with a combination of two products applied together, and with individual mound applications of Maxforce Fire Ant Killer Bait (1.0% hydramethylnon). After application, the greatest percent reduction (90 days) were observed in the Advion/Top Choice combination plots (100.0%), followed by Top Choice alone (96.4%). Advion and MaxForce produced significantly lower foraging reductions at 90 days (61.2% and 27.5% respectively). At the conclusion of the test (day 360), significantly fewer ants were collected in the Advion (777.7), Top Choice (972.8), and combination plots (596.2) than in the control plots (1257.8) (df 13, F = 8.3, P < 0.05). The mean number of ants collected from MaxForce treatment plots was not significantly different from controls (P > 0.05). Overall, the efficacy and residual studies suggested that the Advion/Top Choice combination produced both the most rapid reduction in ant foraging and the longest lasting control (90%) at 300 days. When evaluating time to knockdown of foraging populations, the Advion/Top Choice combination also provided the most complete and rapid results by day 7, reducing foraging by 100%. While other products also performed well (75.6 - 95.9% reductions), both the MaxForce and Advion plots had significant increases in foraging at 30-90 days. Overall, foraging knockdown was the most complete in the Avion/Top Choice combination plots at 90 days