Detrimental sublethal effects hamper the effective use of natural and chemical pesticides in combination with a key natural enemy ofBemisia tabacion tomato

Abstract

Background Bemisia tabaci(Hemiptera: Aleyrodidae) represents one of the greatest threats to agricultural crops. Chemical control is the primary tool used in integrated pest management (IPM) programs. However, release of the predatorNesidiocoris tenuis(Hemiptera: Miridae) on tomato plants is a highly recommended control tactic. The objective of this study was to evaluate the efficacy of a commercial borax plus citrus oil (BCO) product againstB. tabaciin the presence and absence ofN. tenuis. The synthetic insecticide lambda-cyhalothrin was used as a positive control. We also evaluated the sublethal effects of BCO on the behavior and predation rate ofN. tenuis. Results Our results demonstrated that BCO, alone and at its maximum recommended field rate forB. tabaci, was not effective in controlling the pest under laboratory conditions. Application of BCO simultaneous withN. tenuisrelease did not reduce the increase in theB. tabacipopulation. Effective control ofB. tabaciwas achieved using onlyN. tenuis. However, synthetic lambda-cyhalothrin pyrethroid, used here as a control, caused high pest mortality and led to on-site extinction ofN. tenuis, which did not occur for insects exposed to BCO. Lambda-cyhalothrin and BCO significantly affected the foraging behavior ofN. tenuis, reducing the predation rate, especially following exposure to lambda-cyhalothrin. Conclusion The insecticide lambda-cyhalothrin achieved satisfactory results in suppressingB. tabaci, but was harmful toN. tenuis. Additionally, lambda-cyhalothrin and BCO affected predator behavior.