LETHAL AND SUBLETHAL EFFECTS OF IMIDACLOPRID ON NICOTINE-TOLERANT MYZUS-NICOTIANAE AND MYZUS-PERSICAE

Bioassays of nicotine and imidacloprid against clones of Myzus persica e (Sulzer) and Myzus nicotianae (Blackman) from around the world demon strated that some had low levels of resistance to both compounds. This was expressed not only as a reduced mortality, but more markedly as d ifferential inhibition of feeding by imidacloprid concentrations in th e parts per billion range. Such concentrations also reduced aphid fecu ndity by inhibiting the production and viability of nymphs, and this e ffect was more marked for susceptible aphids than for those showing re duced direct lethal and antifeedant effects.