Control of Drosphila spp., Carpophilus spp. and Ephestia figulilella (Gregson) in sultana grapes grown for dried fruit

Abstract

Sultana grapes grown in Australia for dried fruit are attacked by insects before and during harvest, and during drying and storage. Insect damage, including crop loss and contamination of the dried grapes with insect matter, varies between and within seasons according mainly to the incidence of rain damage. The effectiveness of chlorpyrifos for control of vinegar flies (Drosophila simulans Meigen, D. melanogaster Sturtevant), dried fruit beetles (Carpophilus hemipterus L., C. dimidiatus Fabricius, and C. humeralis Fabricius), raisin moth (Ephestia figulilella Gregson), Indian meal moth (Plodia interpunctella (Hiibner)), and saw-toothed grain beetle (Oryzaephilus surinamensis (Linnaeus)) was investigated at Irymple, Victoria, in field experiments during 1979 and 1980. In 1979, pre- and post-harvest treatments of chlorpyrifos, applied at a rate designed to give an initial residue of 25 mg/kg in the grapes, reduced insect infestation in drying and dried grapes. In 1980, chlorpyrifos was applied pre-harvest at three rates designed to give initial residues of 50, 5, and 2 mg/kg, respectively. Treatments of 50 and 5 mg/kg were effective in controlling insects in the fresh, drying and dried grapes for each of four successive harvest occasions, and during storage in a commercial packing shed. Chlorpyrifos 2 mg/kg was less effective than the higher rates in controlling raisin moth, Indian meal moth and saw-toothed grain beetle in the latter phases of the experiment. An application of dip mixture (1 % drying oil plus 17 g/litre K2CO3) suppressed vinegar flies and dried fruit beetles for a short period but had no effect on the other insect pests.