The role of leaf surface characteristics in the mediation of pesticide availability to invertebrates
The role of leaf surface characteristics in the mediation of pesticide availability to invertebrates
The role of leaf surface characteristics in mediating the toxicity of the pesticides deltamethrin and dimethoate to the springtail F. candida and a parasitoid A. colemani has been studied. This study is important for the interpretation of the behaviour of foliar applied pesticides on various plant surfaces and the subsequent transfer of toxicant to the target invertebrates. There have been few quantitative assessments of the fate of pesticide deposits and their action in various crops.
Bioassays on residues showed significant differences in mortality of F. candida on different leaf types. On deltamethrin treated surfaces LD50 values ranged from 6.36 (g AI ha-1) to 77.14 (g AI ha-1). Significant differences in F. candida mortality on three species of cereal crops suggest that it may be necessary to recommend different application rates for different crops, instead of adhering to a conventional single application rate. On dimethoate treated surfaces the range of LD50 values was 1.35 to 8.69 g AI ha-1. F. candida was found to survive on some leaf surfaces that had been sprayed with deltamethrin at a rate of 16 times greater than the field rate. On dimethoate treated surfaces mortality was observed on some leaf surfaces sprayed with over 100 time less pesticide than used in the field.
The amount of wax on various leaf surfaces was positively correlated with the residual toxicity of deltamethrin to F. candida and A. colemani. The lipophilicity of deltamethrin may be an important factor in this correlation. No such relationship between the epicuticular wax content of various leaf types and residual toxicity of dimethoate to F. candida was observed despite significant differences in mortality on different leaf surfaces This highlights the importance of the nature of the active ingredient, the formulation of pesticide, and other leaf surface characteristics in mediating toxicity.
University of Southampton
Chowdhury, A.B.M. Nasir Uddin
d4354a35-9576-42d1-82ab-c4526b0ce2bd
1998
Chowdhury, A.B.M. Nasir Uddin
d4354a35-9576-42d1-82ab-c4526b0ce2bd
Chowdhury, A.B.M. Nasir Uddin
(1998)
The role of leaf surface characteristics in the mediation of pesticide availability to invertebrates.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
The role of leaf surface characteristics in mediating the toxicity of the pesticides deltamethrin and dimethoate to the springtail F. candida and a parasitoid A. colemani has been studied. This study is important for the interpretation of the behaviour of foliar applied pesticides on various plant surfaces and the subsequent transfer of toxicant to the target invertebrates. There have been few quantitative assessments of the fate of pesticide deposits and their action in various crops.
Bioassays on residues showed significant differences in mortality of F. candida on different leaf types. On deltamethrin treated surfaces LD50 values ranged from 6.36 (g AI ha-1) to 77.14 (g AI ha-1). Significant differences in F. candida mortality on three species of cereal crops suggest that it may be necessary to recommend different application rates for different crops, instead of adhering to a conventional single application rate. On dimethoate treated surfaces the range of LD50 values was 1.35 to 8.69 g AI ha-1. F. candida was found to survive on some leaf surfaces that had been sprayed with deltamethrin at a rate of 16 times greater than the field rate. On dimethoate treated surfaces mortality was observed on some leaf surfaces sprayed with over 100 time less pesticide than used in the field.
The amount of wax on various leaf surfaces was positively correlated with the residual toxicity of deltamethrin to F. candida and A. colemani. The lipophilicity of deltamethrin may be an important factor in this correlation. No such relationship between the epicuticular wax content of various leaf types and residual toxicity of dimethoate to F. candida was observed despite significant differences in mortality on different leaf surfaces This highlights the importance of the nature of the active ingredient, the formulation of pesticide, and other leaf surface characteristics in mediating toxicity.
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Published date: 1998
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Local EPrints ID: 463131
URI: http://eprints.soton.ac.uk/id/eprint/463131
PURE UUID: fd4c14f6-1823-49c9-b0f3-02346822ce69
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Date deposited: 04 Jul 2022 20:45
Last modified: 16 Mar 2024 19:02
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A.B.M. Nasir Uddin Chowdhury
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