Toxicities of Topically Applied Insecticides to Western Spruce Budworm, 1977

Topical application tests to determine the toxicities of 16 insecticides were conducted on 6th instar western spruce budworm. Toxicities were compared to that of a standard, mexacarbate. Insects tested were from the 68th generation of a nondiapausing laboratory colony. Five concentrations serially diluted from a freshly prepared concentrate were used in each of 3 replications of each test. All chemicals were applied in reagent grade acetone. Treatment was performed with an ISCO model M microapplicator equipped with a 1/4 cc tuberculin syringe. A dose rate of I 1/100 mg body weight was used to apply the insecticide to the thoracic dorsa of CO2 anesthetized larvae weighing 70-110 mg. After treatment, larvae fed upon artificial diet. Mortality was tallied after 7 days.