New Zealand Journal of Crop and Horticultural Science abstracts

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Short communication

Modelling insecticide residues on kiwifruit foliage:
effect of residue age on insecticide activity and concentration

A. J. GREAVES
A. R. TOMKINS
C. T. THOMSON
D. J. WILSON

The Horticulture and Food Research Institute
of New Zealand
Ruakura Research Centre
Private Bag 3123
Hamilton, New Zealand

Abstract  Chlorpyrifos EC was applied at a range of rates to kiwifruit leaves in an experiment designed to test the adequacy of a published residue decay and activity model for the case of insecticide on kiwifruit. Treated leaves were sampled over a period of 51 days following spray application, with residue levels determined by chemical assay, and residue toxicity to lightbrown apple moth Epiphyas postvittana assessed by bioassay and logit regression analysis. Residue activity indexed as the residue level for 90% mortality (LR90) was shown to decline substantially as residues aged from 2 to 51 days. A log residue-log time model was shown to be a more robust representation of residue decay characteristics than the exponential model frequently used.

Keywords  residue; insecticide; residue model; residual activity; chlorpyrifos; kiwifruit; Epiphyas postvittana

New Zealand Journal of Crop and Horticultural Science, 1994, Vol. 22: 463-467

0114-0671/94/2204-0463 $2.50/0 (c) The Royal Society of New Zealand 1994

PDF file of entire paper: medium quality (355K); (scanned from paper original: notes about this process)

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