Lethal, sublethal and transgenerational effects of insecticides on Macrolophus basicornis, predator of Tuta absoluta

The South American tomato pinworm, Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae), is a key pest in tomato crops worldwide. In Europe, Integrated Pest Management (IPM) programs of this pest focus on releases of generalist mirid predators. In Brazil, Macrolophus basicornis (Stal) (Hemiptera: Miridae) is a potential biological control agent of T. absoluta. However, the compatibility of this predator with insecticides applied on tomato crops must be evaluated. Therefore, the non-target effects of four insecticides (abamectin, chlorantraniliprole, teflubenzuron and methoxyfenozide) were evaluated on the predator M. basicornis. Fourth instar nymphs were exposed to treated tomato leaflets, and their mortality was evaluated over 72h. In those treatments with low mortalities, sublethal effects on developed adults were evaluated (hind tibia length and adult survival). Moreover, the effects on progeny (nymphs/female, development time and hind tibia length) were evaluated in three oviposition dates. Abamectin was very toxic to nymphs, while methoxyfenozide, teflubenzuron and chlorantraniliprole caused low mortalities. Adult survival was not affected by the insecticides, however the growth regulators (teflubenzuron and methoxyfenozide) reduced the tibia length of females during the nymphal stage. The same reduction was observed for female progeny. The number of nymphs originated by exposed females was similar to the untreated control in all treatments. However, development time of M. basicornis progeny increased with the oviposition date, and treatments differed from control only in the last oviposition date. The results of this research indicate that, among the tested chemicals, chlorantraniliprole is the safest insecticide to M. basicornis.