Effectiveness of Insecticides Applied To Concrete for Argentine Ant Control, 1979

Abstract

Residues of 10 insecticides were prepared, tested fresh and after I mo and 6 mo of aging against field collected argentine ant workers in replicated tests. Each chemical was replicated 5 times on one 30.5 cm square concrete stepping stone. Each replicate comprised the area surrounded by a 9 cm diam transparent plexiglas ring ca 2.5 cm tall sealed to the concrete surface with paraffin. The side walls of the plexiglas rings were coated with teflon emulsion to prevent the ants from escaping and humidity was provided by a moistened 5 cm length of dental wick taped to Petri dish lids which were used to cover the plexiglas rings. A replicate series of each toxicant was prepared by pipetting 0.5 ml of 1% or 0.5% water diluted insecticide onto the area within each plexiglas ring and allowing the residues to air-dry for I da. The resulting residues were at the rate of ca 800 mg/m2 for 1% and ca 400 mg/m2 for 0.5% applications. Ants were collected from foraging trails just prior to each test and were continuously exposed in groups of 10-20 workers/replicate until KD-90 minutes was reached. If mortality occurred in control dishes before KD-90s were reached on residues, mortality for each replicate was corrected with Abbott's formula.