|Secondary effects of pyriofenone against several important plant pathogens|
Yuzuka Abe: Ishihara Sangyo Kaisha, Ltd.
<div>Pyriofenone (Property, Kusabi, Prolivo) is a new fungicide developed by Ishihara Sangyo Kaisha to control powdery mildew on various crops. This study investigated the secondary effects of pyriofenone on other pathogens. Antifungal activity testing revealed that pyriofenone strongly inhibited the mycelial growth of <em>Rosellinia necatrix</em> and had moderate effects on <em>Botrytis cinerea</em>, <em>Magnaporthe oryzae</em>, <em>Pseudocercosporella herpotrichoides</em>, and <em>Helminthosporium sacchari</em>. Pyriofenone also inhibited conidial formation by <em>B. cinerea</em>, conidial germination and appressorium formation by <em>M. oryzae</em>, and pycnidium formation by <em>Zymoseptoria tritici</em> <em>in vitro</em>. <em>In planta</em>, pyriofenone exhibited strong preventive and curative activity against white root rot on Japanese pear (<em>Pyrus pyrifolia</em>) and moderate activity against rice blast in pot tests. The control of gray mold with a single foliar spray of pyriofenone was limited, but mixture with other botryticides resulted in better control than with each separate fungicide alone, in both pot and field trials. Although pyriofenone is used specifically to control powdery mildew, when mixed with fungicides from other classes it can also control several other important diseases.</div>