Fungicidal control of botrytis cinerea on four strawberry varieties

Captan, dichlofluanid at a high and a low rate, thiram, and a mixture of captan and thiram were tested in a field trial to control gray mold fruit rot caused by Botrytis cinerea Pers. on the strawberry varieties Gorella, Midway, Redcoat and Sparkle. The mean marketable yield of the varieties was increased by dichlofluanid (low) and thiram but not by the other treatments over that of non-sprayed plots. Dichlofluanid (high) gave better control of pre-harvest fruit rot than captan. Dichlofluanid (high) significantly reduced mean fruit size. Redcoat yields were higher with the low rate than the high rate of dichlofluanid, but pre-harvest fruit rot control and fruit size did not differ with the two rates. Gorella yields and fruit size were smaller with captan + thiram than with captan or thiram. Thiram reduced fruit size on Midway. The varietal reaction to fungicides suggests that marketable yield is the most important variable in selecting a fungicide for the control of gray mold fruit rot of strawberries.