The effect of exposure to imidacloprid on Asian longhorned beetle (Coleoptera: Cerambycidae) survival and reproduction.

The effect of imidacloprid delivery method and application rate on survival of adult Asian longhorned beetles, Anoplophora glabripennis (Motschulsky), was studied, along with the effect of repeated daily ingestion of imidacloprid on the survival and reproductive capacity of adult females. Beetles exposed repeatedly to 50 ppm imidacloprid died in < 2-3 wk, whether dosed orally each day, or through contact exposure. Beetles given 1 microl of 50 ppm imidacloprid daily for two, three, four, or five consecutive days died sooner with increasing consecutive days: the beetles treated for 5 d all died within 15 d, while 80% of beetles treated for only 2 d lived > 8 wk. For females given 1 microl daily, across a range of doses from 2 to 50 ppm imidacloprid, the total number of viable eggs laid was reduced with increasing dosage, but percentage egg viability was not affected. Survival of females at dosages of 10 or 30 ppm/d was not significantly reduced compared with controls but these females laid 23-38% fewer viable eggs, suggesting a sublethal effect of imidacloprid. Female beetles given 1 microl/d of 40 or 50 ppm imidacloprid died more quickly than controls and viable egg production was reduced 82-93%, because of a combination of lethal and sublethal effects of intoxication.