Insecticidal activity of fixed oils on Zabrotes subfasciatus (Boheman) (Coleoptera: Chrysomelidae) in common bean stored

The common bean Phaseolus vulgaris in storage is frequently attacked by insect pests, which reduce the quality of the product. The use of phosphine fumigant insecticide to control stored grain insects has led to the selection of resistant populations, and alternatives are needed. In this context, the objective of this study was to assess the insecticidal effect of grapeseed oil (Vitis vinifera) and canola oil (Brassica napus) on Z. subfasciatus in stored bean. Contact tests were carried out to determine the lethal levels of LC50 and LC95 and their respective toxicity ratios, as well as to observe the number of eggs and insects after 12 and 30 days, respectively. For the repellency test, the number of insects attracted in the lethal concentrations LC50 and LC95 was observed, in addition to the reduction in the number of eggs and emergence. In the contact test, there was no difference in the toxicity of essential oils. Both oils were efficient in the reduction of the oviposition when compared to the control treatment, with canola oil presenting the highest reduction in the number of eggs with increasing concentrations. In the repellency test, the oils were repellent in the concentrations LC50 and LC95. The largest reduction in the number of eggs and insects was found in the grape seed oil.

Automated summary

The insecticidal effect of grapeseed oil and canola oil on Z. subfasciatus in stored bean was assessed. Both oils were found to effectively reduce the number of eggs and insects, with grapeseed oil showing the best results.