Modelling of pesticide residues on fruit II: persimmon

Abstract

A determinstic model for the prediciton of pesticide residues originally developed for kiwifruit has been applied to persimmon. The model accommodates: varying spray programmes (rates, number of applications); separation of physical decay from crop growth; predictions for both short and long preharvest intervals. Decay rate parameters for carbaryl, chloropyrifos, diazinon, dimethoate, permethrin and primiphos-methyl on persimmon have been estimated from residue data (diameter, weight) were used to formulate a growth curve. The model has been implemented as a Microsoft ACCESS database application for personal computer which provides flexible imput of spray diary information and reports summarising predicted residues. The model has been tested by comparison of predicted versus measured (laboratory analysis) residues from three field trials and a survey of fruit from 68 growers in the 1995 harvest season. The model was found to provide reasonable predictions of diazinon, pirimiphos-methyl and permethrin residues at both short and long preharvest intervals.