Susceptibility of Four Species of Aphids in Wheat to Seven Insecticides and Its Relationship to Detoxifying Enzymes.

Peipan Gong,Defeng Chen,Mengyi Li,Xinan Li,Yunhui Zhang,Xun Zhu,Xiangrui Li,Chao Wang

doi:10.3389/fphys.2020.623612

Abstract

Sitobion avenae (Fabricius), Rhopalosiphum padi (Linnaeus), Schizaphis graminum (Rondani), and Metopolophium dirhodum (Walker) (Hemiptera: Aphididae) are important pests of wheat and other cereals worldwide. In this study, the susceptibilities of four wheat aphid species to seven insecticides were assessed. Furthermore, the activities of carboxylesterase (CarE), glutathione S-transferase (GSTs), and cytochrome P450 monooxygenase (P450s) were determined in imidacloprid treated and untreated aphids. The results showed that the susceptibilities of four wheat aphid species to tested insecticides are different and M. dirhodum has shown higher tolerance to most insecticides. Relatively higher CarE and GST activities were observed in M. dirhodum, and P450s activities increased significantly in response to imidacloprid treatment. Moreover, susceptibility to imidacloprid were increased by the oxidase inhibitor piperonyl butoxide in M. dirhodum (20-fold). The results we have obtained imply that P450s may play an important role in imidacloprid metabolic process in M. dirhodum. We suggest that a highly species-specific approach is essential for managing M. dirhodum.

Highlights

The English grain aphid Sitobion avenae, bird cherry-oat aphid Rhopalosiphum padi, greenbug aphid Schizaphis graminum, and Metopolophium dirhodum (Homoptera: Aphididae) are important pests of wheat and other cereals worldwide (Zhang et al, 2019)
We found that the field occurrence of M. dirhodum is more serious than S. avenae and R. padi in the areas such as Beijing and Hebei province where with imidacloprid seed treatment, according to us investigate result in past several years (Li et al, 2019)
To find out what caused the differential susceptibility to insecticide among the four wheat aphids, and clarify the reasons of high insecticide tolerance in M. dirhodum, especially to imidacloprid, we determined the CarE, glutathione S-transferase (GSTs), and P450 monooxygenase (P450s)

Summary

Introduction

The English grain aphid Sitobion avenae, bird cherry-oat aphid Rhopalosiphum padi, greenbug aphid Schizaphis graminum, and Metopolophium dirhodum (Homoptera: Aphididae) are important pests of wheat and other cereals worldwide (Zhang et al, 2019). Sitobion avenae and R. padi are problematic pest aphid species for diverse wheat cultivars grown in various regions (Lu and Gao, 2009; Hu et al, 2016). Metopolophium dirhodum is the most abundant aphid species on cereals in the continental climate of central Europe (Honek et al, 2018). Wheat aphids cause damage by directly feeding on plants and by vectoring multiple plant pathogenic viruses (Lu et al, 2016).

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Conclusion