Comparative toxicity and biochemistry of organophosphates and pyrethroid compounds on both laboratory and field strain of the Cotton Leafworm Spodoptera littoralis (Boisd.)

A., El- Sheikh T. A.

doi:10.21608/eajbsc.2012.16133

Comparative toxicity and biochemistry of organophosphates and pyrethroid compounds on both laboratory and field strain of the Cotton Leafworm Spodoptera littoralis (Boisd.)

Document Type : Original Article

Author

El- Sheikh T. A. A.

Plant Prot. Res. Inst., Agric. Res. Cent., Dokki, Giza, Egypt

10.21608/eajbsc.2012.16133

Abstract

Bioassay was carried out for monitoring resistance spectrum toward insecticides include organophosphates, Dursban H-48% EC (Chlorpyrifos) and pyrethroids Cyper (Cypermethrin 10% EC) in three different field populations (Gharbia , Kalubia and Menofeya Governorates) of the Cotton Leafworm, Spodoptera littoralis (Boisd.). Toxicity data based on LC₅₀ values indicated that the pyrethroid Cyper (Cypermethrin 10% EC) is more toxic insecticide against the laboratory strain, while, the OP Dursban H- 48% EC (Chlorpyrifos) was less toxic. The development of resistance to organophosphates, Dursban H- 48% EC (Chlorpyrifos) and pyrethroids Cyper (Cypermethrin 10% EC) in field strains of the cotton leafworm, in relation to esterases, glutathione s- transferase, and phosphatases was studied. Field strains exhibited moderately high level of resistance to the tested insecticides. A significant increase in the activity of esterases, glutathione s- transferase suggests a good relation to resistance was detected. A high level of acid phosphatase and low level of alkaline phosphatase accompanied the level of resistance to pyrethroid and OP.

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