Metabolic and Behavioral Mechanisms of Indoxacarb Resistance in Sitophilus zeamais (Coleoptera: Curculionidae)

Abstract

The control of the most important pest of stored maize, the weevil Sitophilus zeamais Motschulsky (Coleoptera: Curculionidae), is mainly achieved with the use of pyrethroid insecticides. However, the intensive use of these compounds has led to the selection of resistant populations and has compromised the control efficacy of this insect pest. Here, the toxicity of indoxacarb for a potential use in the control of S. zeamais was assessed on 13 Brazilian populations. Concentration-mortality bioassays, in the presence of synergists (piperonyl butoxide, triphenyl phosphate, and diethyl maleate), were used to assess potential metabolic-based indoxacarb resistance mechanisms. We also assessed the behavioral (locomotory) responses of these populations to indoxacarb exposure. The results showed significant differences between the populations (LD50 values ranged from 0.06 to 13.99 mg a.i/kg of grains), resulting in resistance ratios of >200-fold between the least (Canarana-MT) and the most (Espirito Santo do Pinhal-SP) susceptible populations. The results obtained with synergized indoxacarb suggest the involvement of esterases and glutathione-S-transferases on indoxacarb action, and also suggest the involvement of cytochrome P450-dependent monooxygenases as a potential indoxacarb resistance mechanism in Brazilian populations of S. zeamais. Although indoxacarb-induced behavioral avoidance varied among populations, some resistant populations (e.g., Canarana-MT) were able to reduce exposure to indoxacarb by spending more time in the nontreated areas. Collectively, our findings indicate that the behavioral (locomotory) and physiological responses of these insects may compromise the control efficacy of oxadiazine insecticides (e.g., indoxacarb) in Brazilian populations of S. zeamais.

Locomotory and physiological responses induced by clove and cinnamon essential oils in the maize weevil Sitophilus zeamais

“…Indeed, such resistance mechanisms have been reported for traditional insecticides in some stored pests [28][29][30][31][33][34][35], which reinforces that need of taking this information in consideration before simply replace the use of traditional insecticides by essential oils.…”

“…Two behavioral bioassays were carried out in arenas that were either fully treated or half-treated with essential oils using methodologies that were previously described for synthetic insecticides [33,34,40,42,51]. The control treatments consisted of acetone only.…”

“…It is one of the most destructive and widespread key pests of stored maize [38,39]. The management of this pest in storage facilities relies heavily on the use of chemical insecticides, but many cases of resistance and control failure have been reported because of the inadequate application of this strategy [34,40,41,1995,42,43]. The insecticidal actions of clove and cinnamon oils and their major constituents on S. zeamais have been reported elsewhere [44][45][46][47], but the potential involvement of the respiratory and locomotory strategies used by these insects to mitigate these oil actions have been completely neglected.…”

Monitoramento de insetos e distribuição espacial de Sitophilus spp. (Coleoptera: Curculionidae) em unidade de beneficiamento e armazenamento de grãos

“…Esses inseticidas, quando aplicados de forma inadequada, induzem à resistência de algumas espécies de insetos para determinados compostos ou formulações (HADDI et al, 2015). Assim, diversas alternativas de controle de pragas de armazenamento vêm sendo estudadas, dentre as quais os inseticidas naturais (SOUZA et al, 2012).…”

Respon Genotipe Kedelai Biji Besar Dan Umur Genjah Terhadap Kompleks Hama Pengisap Polong

“…Meskipun telah diaplikasikan secara intensif, tingkat serangan pengisap polong pada kedelai sering masih tinggi, bahkan petani masih sering mengalami gagal panen. Aplikasi insektisida secara terus menerus dapat meningkatkan resistensi hama target dan membunuh serangga berguna (Cordeiro et al, 2014;Afifah et al, 2015;Haddi et al, 2015;Guedes et al, 2016).…”