2-tridecanone is a major constitute of defensive secretion in tawny crazy ants, Nylanderia fulva that is an ant species reported to be able to displace red imported fire ants, Solenopsis invicta in the field. 2-tridecanone was proven to be toxic to S. invicta. Although 2-tridecanone is commercially available, utilization of this naturally occurring compound in fire ant management has received little attention. In this study, toxicity and efficacy of two 2-tridecanone formulations were assessed against S. invicta. Two emulsifiable concentrates were prepared using 2-tridecanone as an active ingredient, vegetable oil as a solvent and polyoxyethylene tridecyl ether as a surfactant. Piperonyl butoxide (PBO) was used as a synergist in one formulation. Both formulations showed significant toxicity in laboratory bioassays. In a field trial, at application rate of 5.28 mL/L and 14 days after mound drench treatment, 100% control was achieved for formulation with PBO and 90% control for the formulation without PBO. In conclusion, both formulations had significant efficacy against S. invicta. Due to the low mammalian toxicity of 2-tridecanone, no involvement of hazardous synthetic organic solvents, no phytotoxicity at applied concentrations, and relatively low cost, both formulations are promising alternatives to commercial insecticide products for fire ant mound drench. The outstanding efficacy of both formulations observed in this study warrants further research on their efficacy against other pest insects.
Defensive Chemical, Fire Ant Control, Mound Drench.