Bioassay Study of Commercial Formulations of Several Insecticides on Platynota idaeusalis123

In a laboratory test, the toxicity of four rates of methomyl, chlordimeform, azinphosmethyl, phosalone, and phosmet was evaluated on the life stages of Platynota idaeusalis (Walker). At 48 h after treatment, azinphosmethyl was the most effective in preventing hatching of 1st instars, and methomyl and azinphosmethyl were the most toxic to 1st and 2nd instars. There was a general decrease in effectiveness of materials as the larvae developed. The insecticides and concentrations included in the tests failed to result in adequate levels of mortality to 3rd, 4th, and 5th instars, and to pupae. All insecticides except chlordimeform were toxic to the adults.