Lethal and sublethal effects of abamectin, acetamiprid and indoxacarb on predatory bug, Nesidiocoris tenuis feeding on tomato leafminer, Tuta absoluta

Behavioral changes of biocontrol agents after exposing to pesticides have an important role in success of IPM programs. In the current study lethal and sublethal effects of abamectin, acetamiprid and indoxacarb as the widely used insecticides were investigated on adults of mirid bug, Nesidiocoris tenuis and its behavior on Tuta absoluta eggs. Experiments were performed in the laboratory conditions (25±1ºC, 60±10% R.H. and 16:8 (L:D) photoperiod). Effects of sublethal concentration of insecticides were evaluated during 24 h period using dried residues of insecticides on tomato leaf. The values of LC50 for abamectin, acetamiprid and indoxacarb against N. tenuis were 33.40, 36.55 and 204.43 and of LC30 were 20.42, 30.38 and 181.53 µl a.i./L, respectively. All insecticides decreased attack rate of the predator; however, the most effective one was indoxacarb. On the other hand, indoxacrab and acetamiprid caused significact increase in handling time of predator while the most effective was indoxacarb. Abamectin showed the lower behavioral effects among the tested insecticides. According to total effect index (E) in IOBC category, acetamiprid (85%) and indoxacarb (77%) were harmful against N. tenuis predatory bug, while, abamectin (38%) was considered as slightly harmful.