Pestic. zyxwvutsrqpon Sci. zyxwvutsrqp 1991, zyxwvutsr 31, 325-335 Influence of Fungicidal Control of Cucumber and Tomato Grey Mould (Botrytis cinerea) on Fruit Yield Hisham Yunis, Yigal Elad Department of Plant Pathology, ARO, The Volcani Center, Bet Dagan 50250, Israel zy & Yitzhak Mahrer Department of Soil and Water Sciences, Faculty of Agriculture, The Hebrew University of Jerusalem, Rehovot 76100, Israel (Revised manuscript received 18 September 1990; accepted 5 October 1990) ABSTRACT zyxw The fungicides tebuconazole, tebuconazole + dichlofluanid, fenethanil, diethofencurb + carbendazim, and vinclozolin combined with chlorothalonil were tested for their ability to control grey mould (Botrytis cinerea Pets. ex Fr.) of cucumber and tomato grey mould in greenhouses under commercial conditions. In winter 1987188 the number zyxw of diseased female fruits of cucumber (Cucumis sativus L.) was reduced by diethofencarb + carbendazim (2.5 mg dni- each) by 93% and by tebuconazole (2.5 mg dm- ’) (phytotoxic when alone) or tebuconazole (1 mg dm - 3, + dichlojluanid (4 mg dm- 3, by 54-57%. Vinclozolin (5 mg dm- 3, + chlorothalonil (25 mg dm- 3, signifi:cantljg reduced diseuse incidence on fruits by 40%. Infection foci on cucumber stems were significantly decreused by vinclozolin + chlorothalonil. A more pronounced decrease was obtained with diethofencurb + carbenduzim, tebuconazole, or tebuconazole + dichlofluanid. During the season of winter 1988189, tebuconazole+ dichlofluanid (1.5 +6 and 34- 12 mg dm - 3, and RH7592 (1 mg dm- j significantly reduced diseased fruits by 30-71%. Grey mould of tomato (Lycopersicon esculentum Mill.) leaves was reduced by more than 90% and on fruits by 7847% when tebuconazole + dichlofluanid (1.5 + 6 and 3 + 12 mg dm- ) or diethofencarb + carbendazim (2.5 my dm- each) were applied. Yields of cucumber fruits of the common purthenocarpic cv. Kasem 292 were weighed. There was no correlation between disease level and yield in any experiment, 325 Pestic. Sci. 0031-613X/91/$03.50 zyxwvu (0 1991 SCI. Printed in Great Britain