Acta Entomologica Sinica (2003) 46, 578-583

Fei Li, Zhao-Jun Han and Bo Tang (2003)
Insensitivity of acetylcholinesterase and increased activity of esterase in the resistant cotton aphid, Aphis gossypii Glover
Acta Entomologica Sinica 46 (5), 578-583
Abstract: Resistant levels of cotton aphid strains collected from five different districts, Taian, Laiyang, Nanjing, Beijing and Anyang in China, designated as strain I , II , III , IV and V respectively, were determined with leaf-dip bioassay. The results indicated that strain V was the highest resistant while strain I was the lowest resistant to conventional organophosphorus (OP) and carbamate pesticides, such as methamidophos, monocrotophos, pirimicarb and thiodicarb. Generally, the resistant levels of the five resistant strains were: V > IV > III , II > I . Compared with the sensitive strain 81-171B, the sensitivity of acetylcholinesterase (ACNE) from strain II , IV and V apparently decreased and that from strain I and III were relatively sensitive. The apparently decreasing of Km value indicated that AChE from strain IV and V have been changed in quality. Esterase (total esterase and carboxylesterase) activity increased dramatically in different resistant strains. Esterase activity of strain III is two times that from stain II . Specially, Km value of carboxylesterase from strain V reached 2460.4 µmol/L and that from strain IV decreased to 84.4 µmol/L. It could be deduced that both increased esterase activity and reduced target sensitivity existed in all resistant strains. For low-level resistant cotton aphid strain, increased esterase activity plays a much more important role. However, either apparently increased esterase activity or reduced AChE activity in cotton aphid may result in middle-level resistance. Both dramatically increasing of esterase activity and reduction of AChE sensitivity are presented in high-level resistant strains of cotton aphid.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Database assignments for author(s): Zhaojun Han

Research topic(s) for pests/diseases/weeds:
pesticide resistance of pest

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Aphis gossypii