Molecular mechanisms of resistance to some pesticides in the two-spotted spider mite Tetranychus urticae (Acari: Tetranychidae) from Egypt

Mohamed S. Salman1, Akram M. Abouzied2*, Ayat K. El-Gammal1, Ahmed H. Abo-Ghalia2

Abstract

ABSTRACT

The two-spotted spider mite, Tetranychus urticae (Acari: Tetranychidae), is the major pest affecting

crops in Egypt. To date, synthetic acaricides are used extensively to control it. These include two specific

acaricides: i.e. abamectin and chlorfenapyr compounds that are toxic to T. urticae and used widespread in

Egypt. Nevertheless, progressive insensitivities to these acaricides are problematic in many areas under

field conditions currently used in Ismailia province, Egypt, to control mites. The overall aim of the

present study was to study the molecular mechanisms of resistance to the pesticides abamectin and

chlorfenapyr in the two-spotted spider mite collected from Ismailia governorate in Egypt. In this paper,

we investigated T. urticae collected from sprayed vegetables, fruits and citrus by compounds abamectin

and chlorfenapyr where control failures were reported, together with a laboratory strain collected from

unsprayed districts. Oligonucleotide specific primers of T. urticae diagnostics were used to screen the

genomic DNA as templates based on the end-point PCR analysis. In the present work, searching of T.

urticae DNA by PCR for resistance mutations revealed that the amplified DNA fragments had the

expected resistant common kinds of mutations. The resulting PCR products were sequenced and

compared with the laboratory strain collected from unsprayed districts. Neither mutation was detected in

DNA samples of the laboratory strains examined in this study. So, it could be that the toxicological and

mutation mechanisms data of abamectin and chlorfenapyr resistance determined in this study will be

essential in devising the resistant management strategies for the future use of these compounds in the

cultivation in Egypt.


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