Control of postharvest Botrytis fruit rot with preharvest fungicide applications in annual strawberry

The control of postharvest Botrytis fruit rot was evaluated during 1997-98 and 1998-99. Weekly applications of captan and thiram were examined at two or three different rates, respectively. Iprodione applications were combine d with the captan and thiram treatments and also applied alone for two peak bloom periods. Strawberry fruit were harvested and graded twice weekly for marketable yield and preharvest incidence of Botrytis fruit rot. For posth arvest evaluations, fruit from four harvests were selected and stored at 4 degreesC, and Botrytis fruit rot incidence was recorded over 14 days of sto rage. Fungicide treatments reduced the incidence of preharvest Botrytis fru it rot and increased marketable yield. The incidence of postharvest Botryti s fruit rot was significantly affected by harvest date, length of time in s torage. and fungicide treatment. The highest rate captan and thiram treatme nts had the least Botrytis fruit rot and the longest storage life. Reduced- rate captan and thiram treatments generally did not provide the same contro l as their respective high-rate treatments. Iprodione added to either the c aptan or thiram treatments did not consistently reduce the preharvest or po stharvest incidence of Botrytis fruit rot or increase yield. Regular, full- rate fungicide treatments appear to be necessary to control Botrytis fruit rot in Florida and to provide the storage life necessary to reach distant m arkets.