Abstract
Benzoates (naturally occurring plant toxins) produce pesticidal effects on various pest insects and mites, but their effects on non-target insects are poorly understood. In this study, we evaluate the lethal and sublethal toxicity of methyl benzoate (MB) to adults of the generalist predatory bug Nesidiocoris tenuis (Reuter) (Hemiptera: Miridae). To assess lethal effects, N. tenuis was exposed to plant surfaces treated with 0.25%, 0.5% and 1% MB, as well as negative and positive controls (water and the neonicotinoid acetamiprid, respectively). Exposure to 1% MB resulted in the highest corrected mortality of 17.8% and 13.3% under laboratory and greenhouse conditions, respectively. Thus, 1% MB can be classified as harmless to N. tenuis according to the International Organization for Biological Control rating scheme. At the sublethal level, MB exposure did not significantly affect the consumption of eggs of the whitefly Bemisia tabaci by N. tenuis relative to negative control feeding rates. In contrast, acetamiprid at the manufacturer’s recommended concentration reduced N. tenuis feeding activity by 45.4%. Furthermore, in a Y-tube olfactometer assay, there were no significant differences between the olfactory responses of N. tenuis to MB concentrations and the negative control (water). This study therefore suggests that MB could be used safely for pest control in combination with N. tenuis.
Highlights
Integrated pest management (IPM) approaches, in which both biological and chemical control agents are applied against pests, are favored over pesticide-only approaches in sustainable production systems [1,2]
The ultimate goal of the present study was to enhance our knowledge of pest control methods suitable for IPM programs, and to ensure that methyl benzoate (MB) was safe for use with
Our results showed that the insecticidal toxicity of 1% MB could be classified as harmless to N. tenuis according to the International Organization for the Biological and Integrated Control of Noxious Animals and Plants, West Palearctic Regional Section
Summary
Integrated pest management (IPM) approaches, in which both biological and chemical control agents are applied against pests, are favored over pesticide-only approaches in sustainable production systems [1,2]. The use of broad-spectrum chemicals in pest management can have negative effects on a target pest’s natural enemies and may impact the efficacy of these enemies as biological control agents [3,4,5]. Further research into the adverse effects of pesticides on natural enemies is crucial for maintaining and improving the effectiveness of biological control systems and for evaluating the suitability of pesticides in IPM programs [1]. Such research should assess the lethal and sublethal effects of chemical pesticides on natural enemies. For the natural enemies of pest species, the risk assessment of pesticides is generally based on both lethal and sublethal effects. Evaluation of Insects 2020, 11, 377; doi:10.3390/insects11060377 www.mdpi.com/journal/insects
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