Impact of a semiochemical insecticide (Slam (R)) on abundance of beneficial insects in corn

A two-year study was conducted in central Texas (Bell County) to investigat e the effects of foliar applications of a semiochemical insecticide, Slam(R ), applied for control of adult Mexican corn rootworm, Diabrotica virgifera zeae Krysan & Smith, on field populations of beneficial arthropod predator s and parasites. Pretreatment counts were made in five fields that were to be treated and five fields that remained untreated. Arthropod abundance was assessed at 7 and 14 days after treatment by placing field-collected corn plants in Berlese funnels. The arthropods were identified after the plants had been in the Berlese funnel for 36-38 hours. In most instances, there wa s no significant impact on abundance of beneficial arthropods from the appl ication of Slam.(R) Of eight groups of adult beneficial arthropods, the tre atment had a significant negative impact only on abundance of adult Coccine llidae other than Scymnus spp. at 14 days following treatment; however, the abundance of this arthropod was extremely low (1-8 insects per 100 plants) . For the immature arthropods, Slam(R) treatment had a significant impact o nly on immature Orius spp. 7 days following treatment; however, this popula tion recovered 14 days after treatment. The parasitism of corn earworm eggs was unaffected by the insecticide application. The abundance of Mexican co rn rootworm adults was reduced by 81% and 94% at 7 and 14 days after treatm ent, respectively.