Effect of fosetyl aluminium and captafol on red core disease and fruit yield of established strawberries.
Fosetyl-Al applied once, as a spray in the autumn after fruit picking, gave very good control of Phytophthora fragariae and significantly increased the number of healthy roots and marketable fruit yield in 2-yr-old Redgauntlet strawberry plants. Fosetyl-A1 applied twice, after fruit picking and in spring, further increased the number of healthy roots, but yields were not significantly better than the single treatment. A half-rate spray of fosetyl-A1 plus a half-rate drench of captafol applied after picking and in spring gave good disease control and a yield significantly better than all other treatments. In the same crop the following year, both of the twice-yearly treatments gave a significant reduction in red core recorded in Sep. and the 2 fungicides together gave a significant increase in fruit yield. In a second trial, a half-rate spray of fosetyl-A1 plus a half-rate drench of captafol applied after picking and in spring again gave good disease control and significantly increased fruit yield. Timing fungicide application, both after fruit picking and in spring according to root development (5 mm or 15-20 mm), had no effect on the level of red core control and little effect on fruit yield. The half-rate fosetyl-A1 plus half-rate captafol treatment was significantly less effective when captafol was applied as a spray rather than as a drench.