side-effects of imidacloprid, dichlorvos, pymetrozine and abamectin, on orius albidipennis (reuter) (hemiptera: anthocoridae)

a 'worst case' laboratory method was employed for evaluating total effect of four pesticides (imidacloprid dichlorvos pymetrozine and abamectin) on the nymphs mortality and adults reproduction in orius albidipennis reuter (hemiptera: anthocoridae). the bioassays were carried out in laboratory using drum cell method under controlled conditions of: 27±1?c rh of 65±5% and 16 h photo phase. the effects of the pesticides were assessed on the n1 stage and determined by the total effect considering the mortality rate and oviposition reduction in audlts. toxicity effects were classified according to scale proposed by iobc. corrected mortality percentages (ma) were 75.55±8.59 50.22±6.34 32.88±4.81 and 28.28±2.37 for imidacloprid dichlorvos abamectin and pymetrozine treated populations respectively. for the pesticides mean no of eggs/female (r) were 15.56 ±7.61 38.44±15.25 6.89±5.56 10.22±5.71. the pesticides' effect on ovipositon (er) was recorded 0.54±0.24 1.33±0.49 0.33±0.29 0.35±0.16 and while the total effect (e) being 86.76±5.75 33.82±4.20 77.92±9.67 74.94±11.77% respectively. according to iobc standards dichlorvos was classified in class ii (slightly harmful) abamectin and pymetrozine with se being taken into account were classified in class ii to iii (slightly to moderately harmful) whereas imidacloprid standing in class iii (moderately harmful). further investigations are recommended on all of the chemicals and under semi field conditions.