Susceptibility to acaricides and detoxifying enzyme activities in the red spider mite, Oligonychus coffeae Nietner (Acari: Tetranychidae)

Somnath Roy,Bipanchi Deka,Anjali Km Prasad,Gautam Handique

doi:10.24349/acarologia/20184261

Abstract

Susceptibility of red spider mite, Oligonychus coffeae Nietner (Acari: Tetranychidae), collected from conventionally-managed (synthetic acaricide usage) versus an organicallymanaged (no acaricide usage) tea plantations in Assam, India, to five synthetic acaricides was determined in laboratory bioassays. Activity of three principal detoxifying enzymes of these mite populations was also assayed. The median lethal concentrations (LC50) of ethion, dicofol, propargite, fenpropathrin, and fenazaquin were 1049.75, 599.21, 232.03, 11.44, and 6.75 ppm, respectively. Field rates of these acaricides were compared with 95% lethal concentration (LC95 in ppm) values, and a decrease in the susceptibility of the test population to ethion, propargite, dicofol and fenpropathrin was observed. There was no change for fenazaquin which was effective at lower doses than the recommended dose. Of all the acaricides tested, fenazaquin was the most toxic and ethion was the least toxic. General esterases (GEs), glutathione- S-transferase (GST), and cytochrome P450 monooxygenases exhibited a higher activity in mite population from the conventionallymanaged tea plantation as compared with the activity in mites from the organicallymanaged tea plantation. These findings may be helpful in the selection of acaricides and in developing resistance management strategies for an effective management program for this major tea pest.

Highlights

Red spider mite, Oligonychus coffeae Nietner (Acari: Tetranychidae), is a highly pervasive polyphagous spider mite pest that infests nearly 133 crops cultivated worldwide (Roy et al 2014a, Migeon et al 2011)
The General esterases (GEs), GST, and Cytochrome P450 monooxygenases (CYP450) activity levels observed in the population from the conventionally-managed plantation were 2.83, 1.68, and 1.31 higher than the levels observed in the susceptible population obtained from the organically-managed plantation
The development of resistance/tolerance is related to the history of exposure of the target pest to commonly-applied insecticides or pesticides similar chemical groups (Zhu et al 2011, Das et al 2017)

Summary

Introduction

Oligonychus coffeae Nietner (Acari: Tetranychidae), is a highly pervasive polyphagous spider mite pest that infests nearly 133 crops cultivated worldwide (Roy et al 2014a, Migeon et al 2011). O. coffeae causes the maintenance foliage to turn red which reduces the photosynthetic capacity of leaves, resulting in defoliation of these infested leaves which, in turn, leads to reduced growth of young shoots (Gotoh et al 2001).For many decades, synthetic acaricides, namely organochlorines, organophosphates, and synthetic pyrethroids, have been routinely used to manage the pest in tea production. Repeated applications of the acaricides combined with the mite’s high reproductive capacity and short life cycle have facilitated the development of resistance of these commonly-used chemistries (Roy et al 2014a). Acaricide resistance in mite pest can result from

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