ON THE CHEMICAL CONTROL OF OPHIOSTOMA ULMI WITH STEROL BIOSYNTHESIS INHIBITORS IN VITRO AND IN VIVO

摘要

A number of inhibitors of sterol biosynthesis have been tested on their activity against Ophiostoma ulmi, the fungus causing Dutch elm disease. Because O.ulmi is a dimorphic fungus showing yeast-mycelium conversion, the inhibitors were tested on both the yeast phase and the mycelial phase. The most active compounds in vitro were: fenpropimorph, imazalil, triflumizole, and prochloraz. It was shown that these inhibitors block the conversion of O.ulmi from yeast to the mycelial phase and force the mycelial phase into the yeast phase. The mycelial phase proved to be the most sensitive stage. In treated cells an irregular deposition, probably of chitin, was observed.