Podisus nigrispinus (Dallas) (Heteroptera: Pentatomidae) is an important biological control agent of the cotton leafworm [Alabama argillacea (Hübner)] in the cotton crops in Brazil. The use of selective products such as pyrethroids has been emphasized in this agroecosystem. Then, the susceptibility of the predatory stinkbug P. nigrispinus to the pyrethroid insecticide gamma-cyhalothrin was studied in the laboratory. Nymphs and adults of the predator were exposed to seven concentrations of the gamma-cyhalothrin via topical contact and ingestion through treated water. The concentrations studied of this insecticide via topical application were relatively harmless for adults of P. nigrispinus (females: LC50 = 143.5 ppm a.i., and males: LC50 = 145.1 ppm a.i.) and 5th-instar nymphs (LC50 = 103.9 ppm) as compared to via ingestion (females: LC50 = 1.98 ppm a.i., males: LC50 = 1.91 ppm a.i., and 5th-instar nymphs: LC50 = 2.05 ppm a.i.). The use of pyrethroids and beneficial insects in IPM programs should be better evaluated.
cotton; biological control; pyrethroid; selectivity; natural enemies