Detrimental sublethal effects hamper the effective use of natural and chemical pesticides in combination with a key natural enemy of Bemisia tabaci on tomato.

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) programmes. However, the release of the predator Nesidiocoris tenuis (Hemiptera: Miridae) in tomato plants is highly recommended as a control tactic. The objective of this study was to evaluate the efficacy of the commercial borax plus citrus oil (BCO) product against B. tabaci in the presence and absence of N. tenuis. The synthetic insecticide lambda-cyhalothrin was used as a positive control. Additionally, we evaluated the sublethal effects of this botanical insecticide on the behaviour and predation rate of N. tenuis. RESULT: Our results demonstrated that BCO, alone and at its maximum recommended field rate for B. tabaci, was not effective on controlling this pest under laboratory conditions. The simultaneous application of this botanical insecticide and N. tenuis release was not able to reduce the increase in the B. tabaci population. The effective control of B. tabaci was achieved using only N. tenuis. However, the synthetic lambda-cyhalothrin pyrethroid tested here as a standard reference caused high mortality of the pest and led to the on-site extinction of N. tenuis, which did not occur for insects exposed to BCO. Lambda-cyhalothrin and BCO significantly affected the foraging behaviour of N. tenuis, reducing the predation rate, especially following exposure to lambda-cyhalothrin.
CONCLUSION: The insecticide lambda-cyhalothrin achieved satisfactory results on suppressing B. tabaci, yet it was harmful to N. tenuis. Additionally, lambda-cyhalothrin and BCO affected the predator's behavior. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.