Scolytus Multistriatus, Laboratory Bioassay, 1974-75

Twenty insecticides were topically applied to the smaller european elm bark beetle and their relative order of toxicity to adult beetles was determined by bioassay. Insects had been collected from branches of infested American elms brought into the laboratory. Each insecticide was serially diluted in acetone and applied to the venter of cold (5°C) adults with an ISCO model M microapplicator equipped with a 1/4 cc tuberculin syringe. The dose rate was 1 μl/10 mg body weight. Adults averaged 3 mg. After treatment insects were held in moist powdered cellulose (alphacel) until mortality observations were made at 3 days. Data were analyzed by the log-dose probit method.