Side effects of insecticides commonly used against Tuta absoluta on the predator Macrolophus basicornis

Abstract

Macrolophus basicornis (Stal) (Hemiptera: Miridae) is a promising biological control agent against tomato pests, mainly the South American tomato pinworm Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae). Nevertheless, the amount of pesticides used in tomato crops could compromise the effectiveness of M. basicornis in pest control. Thus, the present research aims to evaluate the lethal and sublethal effects of five insecticides (spinetoram, chlorantraniliprole + abamectin, triflumuron, tebufenozide, and abamectin) commonly used in tomato crops on M. basicornis. Third instar nymphs were exposed to dry residues of insecticides on tomato seedlings, and adults were directly sprayed using a Potter precision tower. Abamectin caused the highest mortality rate (79.98%) of M. basicornis nymphs. Females exposed to spinetoram during the nymphal stage showed a reduction in tibia length. Except for spinetoram, all other insecticides significantly influenced adult longevity. All insecticide treatments caused a reduction in female offspring. However, the growth of males and females (F1 generation) issued from adults treated did not differ significantly from the control. In the predator flight bioassay, males in the first evaluation showed a reduction in flight activity following exposure to chlorantraniliprole + abamectin and to tebufenozide. Overall, all insecticides tested caused negative effects on M. basicornis.