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Synthetic and natural insecticides have successfully controlled the Indian meal moth (Plodia interpunctellaHübner). However, little is known about how Indian meal moth reacts in a stressed environment caused by synthetic and botanical insecticides. Therefore, this study compared the effects of dichlorvos (DDVP) and ginger (Zingiber officinaleL.) rhizome extract oil on larval and adult mortality, hatchability and adult emergence, and on neurotransmitters and digestive enzymes of Indian meal moth under laboratory conditions of 75 ± 5% relative humidity and 25 ± 5 °C. The insects were exposed to different concentrations of 0.1, 0.2, 0.3, 0.4, and 0.5% of dichlorvos and ginger extract oil for 96 h. Ginger rhizome extract oil caused 100% mortality in newly emerged adult Indian meal moths within 96 h at all concentrations. DDVP and ginger extract oil were ineffective against the third instar larval stage of the Indian meal moth, at varying concentrations that caused adult mortality. DDVP and ginger rhizome extract oil significantly affected digestive enzymes and acetylcholinesterase activities at lethal concentrations used in treatment. Protease activity was significantly increased in larvae exposed to extract oil than DDVP. Acetylcholinesterase activities in the adult insects exposed to maize grains treated with DDVP were higher than those exposed to maize treated with ginger extract oil. DDVP and the ginger extract oil have significant effects on the digestive enzymes. Nevertheless, ginger extract oil increased larval protease activity more than DDVP.

Background: Indian meal moth (Plodia interpunctella) is a significant pest infesting stored grains, particularly maize. Over time, synthetic insecticides have been employed to control insect. The residual effects posed on non-target organisms have called for replacement of synthetic insecticides with botanicals. This study therefore aimed at comparing the insecticidal consistency and oxidative stress invoked by dichlorvos (DDVP) and the oil extract of ginger (Zingiber officinale) on Indian meal moth infesting maize. Disinfested maize grains were treated with DDVP and ginger oil extract separately. Adults P. interpunctellawere introduced to the treated grains daily using complete replacement method. The percentage mortality was calculated daily for 10 d. Furthermore, the oxidative stress caused by DDVP and ginger oil extract on the moth was evaluated by measuring the level of some oxidative stress biomarkers such as glutathione S-transferase, superoxide dismutase, glutathione peroxidase (GPx), and catalase (CAT) activity in the exposed insects. Results: Preliminary results indicated that both DDVP and ginger oil extract exhibited insecticidal properties against Indian meal moth infesting maize. However, the insecticidal (active) period of ginger oil extract was found to be longer than that of DDVP. Nevertheless, DDVP provoked greater oxidative stress in the exposed moth. Conclusions: Ginger oil extract and DDVP show potential for controlling Indian meal moth infestations in stored maize. Yet, ginger oil offers a longer-lasting effect on pest suppression and control. Consequently, it could be a replacement or synergistic insecticide with DDVP to provide ecofriendly insecticide application.