Relative Toxicity and Residue Stability of Insecticides for Harvester Ant Control, 1979

Abstract

Abstract Residues of 10 insecticides were prepared, tested fresh and after I mo and 6 mo of aging against field collected harvester ant workers in replicated tests. Tests were run in 9 cm Petri dishes each with a 9 cm filter paper attached to the bottom by a fine peripheral bead of paraffin. Side walls of the dishes were coated with teflon emulsion to prevent the ants from escaping. A 5 replicate series of each toxicant and concentration was prepared by pipetting 0.5 ml of 1% or 0.5% water diluted Insecticide onto each filter paper and allowing them to dry for I da. The resulting residues were at the rate of ca 800 mg/m* for 1% and ca 400 ma/m** 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 were reached. If mortality occurred in control dishes before KD-90's were reached on residues, mortality for each replicate was corrected with Abbott's formula.