Abstract

PAL, Elisa et al. Lethal and sublethal effects of insecticides on Bathycoelia distincta (Heteroptera: Pentatomidae). AE [online]. 2024, vol.32, pp.1-9. ISSN 2224-8854.  http://dx.doi.org/10.17159/2254-8854/2024/a16992.

Bathycoelia distincta is one of the most dominant stink bug pests associated with macadamia orchards in South Africa. Understanding the toxicity and sublethal effects of insecticides on this pest is essential for its effective management. This study tested four commercial insecticide formulations, consisting of one organophosphate (acephate) and three pyrethroids (lambda-cyhalothrin, beta-cyfluthrin and tau-fluvalinate). The toxicity of these insecticides and their behavioural effects on mobility were assessed. The sublethal effects of lambda-cyhalothrin on the biological parameters of parent B. distincta (F0) and offspring generations (F1) were also determined by treating B. distincta adults with sublethal concentrations (LC₁₀ and LC₃₀). In toxicity bioassays, acephate was more toxic to B. distincta than lambda-cyhalothrin, beta-cyfluthrin and tau-fluvalinate. Behavioural changes were only observed in bugs exposed to pyrethroids, resulting in an increase in the distance walked and decrease of angular velocity. In the F0 generation, LC₃₀ reduced the fecundity whereas the LC₁₀ and LC₃₀ accelerated development of the F1 generation. These results suggest that pyrethroids may enhance the dispersal of this pest and stimulate the growth of offspring populations. Further experiments should be conducted to confirm these results and understand the mechanism of action of pyrethroids on B. distincta.

Keywords : stink bug; toxicity; pyrethroids; macadamia.

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