THE DISTRIBUTION AND PERSISTENCE OF IPRODIONE APPLIED BY THERMAL FOGGING IN A GLASSHOUSE TOMATO CROP

Deposits collected on filter paper after application of a ready-to-fog formulation of iprodione and the residues of iprodione washed from tomato leaves after fog and HV [high-volume] spray application were analyzed by GLC. Relatively heavy deposits were found close to the fogging machine, but the deposit became lighter with increasing distance from the machine and in positions lateral to the stream of fog. The deposit collected within the leaf canopy was considerably ligher than that collected above the plants. Residues of iprodione on plants treated with HV sprays were always considerably higher than on fogged plants given a comparable rate of application. After repeated treatment, a substantial build-up of residue was found, but the amount on fogged plants was approximately half that on plants treated with HV sprays. There was a good correlation between the residue found on plants at 6 positions within the glasshouses and the incidence of infection from artificial inoculations of Botrytis cinerea on petioles.