Careful choice of insecticides in Integrated Pest Management strategiesin maize conserves Orius spp. population in the field

Abstract: A field experiment was set up in April 2011 at Legnaro, Italy, within the EuropeanProject PURE, to evaluate two IPM strategies against a conventional one in four-year maizebasedcropping systems that will involve different crops in the rotations in subsequent years.Three different foliar insecticide treatments were applied to the first-year maize against thesecond generation larvae of Ostrinia nubilalis (Hübner) according to the strategy followed.Lambda-cyhalothrin was applied as the conventional strategy, while chlorantraniliprole, aninsecticide selective to beneficial arthropods and a biological insecticide containing Bacillusthuringiensis var. kurstaki were applied as the two IPM-based strategies. The minute pirate bug(Orius spp.) was the most abundant among the beneficial organisms and was considered as theindicator species in this study. Statistical analysis showed no significance difference betweenstrategies in Orius spp. density before the insecticide treatments, whereas after treatments Oriusspp. was significantly lower in the conventional strategy compared to the IPM-based strategies.Ostrinia nubilalis damage was slightly higher when treated with the biological insecticidecompared to the other two strategies. Treatment with chlorantraniliprole did not affect Orius spp.population confirming its selectivity to this species. The primary results of this study reveal thatthe careful choice of insecticides that exhibit selectivity to beneficial organisms and the inclusionof biological insecticides into IPM strategies in maize can promote conservative biologicalcontrol.