THE QUANTAL RESPONSE OF 2 FLEA BEETLES, PODAGRICA-SJOSTEDTI (JACOBY) AND P-UNIFORMA (JACOBY) (COLEOPTERA, CHRYSOMELIDAE) TO DIFFERENT DOSESAND METHODS OF APPLICATION OF LAMBDACYHALOTHRIN, KARATE, IN A LABORATORY

In laboratory trials carried out on flea beetles, Podagrica sjostedti and Podagrica uniforma, different doses of lambdacyhalothrin were appl ied topically on the mesonotum of the insect or on the substratum wher eupon the insects crawled and made contact, or on feed materials offer ed to starved insects. Topical application revealed high (P < 0.01) co ntact activity resulting in LC(50) values of 3.0 mu g kg(-1) for P, un iforma and 2.9 mu g kg(-1) for P, sjostedti, as did exposure of insect s to wet deposits of the chemical when LC(50) values of 13.9 mu g cm(- 2) for P. uniforma and 13.4 mu g cm(-2) for P. sjostedti were obtained . On the other hand, exposure to dry deposits revealed little or no re sidual contact activity. However, the flea beetles which failed to fee d on leaf discs with wet deposits of lambdacyhalothrin fed on leaf dis cs with dry deposits and, in the event took in enough chemical which k illed them through stomach action. Poisoned leaf discs remained effect ive for up to 42 days after initial treatment. Lambdacyhalothrin did n ot show any systemic activity and feeding on leaves that developed aft er plants had been sprayed did not kill the flea beetles.