Acta Entomologica Sinica (2003) 46, 691-696

Bo Liu, Xi-Wu Gao and Bing-Zong Zheng (2003)
[Effects of sublethal doses of anticholinesterase agents on toxicity of insecticides and their induction to acetylcholinesterase (AChE) activity in Helicoverpa armigera]
Acta Entomologica Sinica 46 (6), 691-696
Abstract: Effects on toxicity of insecticides by sublethal doses of anticholinesterase agents (phoxim, malathion and methomyl) and their induction of AChE specific activity, the Michaelis constants (K_m) were investigated in the larvae of the cotton bollworm, Helicoverpa armigera (Hübner) . The results indicated that toxicity of five insecticides had significant differences at 24 hours after treatments. The ACNE specific activity of cotton bollworm was moderately depressed at 24 hours after treatment with LD₁₀ of phoxim. The time-course study revealed that the maximum induction of AChE specific activity by malathion and methomyl was observed at 3 h and 12 h after treatment, resulting in a 1.45-fold and 1.92-fold increase of AChE activity, respectively. The sublethal dose of phoxim had no effect on the affinity of AChE toward acetylthiocholine in 48 hours after treatment, but AChE affinities were significantly reduced after treatment with LD₁₀ of malathion and methomyl. The density gradient centrifugation showed that the distribution of AChE activity in the 5 % gradient layer was higher than the control at 24 hours after treatment with sublethal doses of anticholinesterase agents, but lower in the 20% gradient layer. It was inferred that treatment of sublethal doses may cause the changes in molecular forms and the distribution of different molecular forms of AChE.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
(original language: Chinese)
Database assignments for author(s): Xi-Wu Gao

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

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Helicoverpa armigera