APPLICATION RATES AND SPRAY INTERVALS OF ERGOSTEROL-BIOSYNTHESIS INHIBITOR FUNGICIDES FOR CONTROL OF ENTOMOSPORIUM LEAF-SPOT OF PHOTINIA

The ergosterol-biosynthesis inhibitor (EBI) fungicides myclobutanil, t ebuconazole, diniconazole, and flusilazole were compared with chloroth alonil and triforine for the control of Entomosporium leaf spot on pho tinia. Applied weekly, myclobutanil (0.15 g a.i./L) was equal to or be tter than chlorothalonil (1.35 g a.i./ L) for control of leaf spot, an d these two fungicides were superior to triforine. Tebuconazole and di niconazole provided good disease control but reduced growth of plants. Application of myclobutanil at 2-wk intervals was efficacious in cont rolling disease. All of the fungicides tested controlled Entomosporium leaf spot, but only myclobutanil caused no phytotoxicity to photinia.