VIEW ARTICLE

Molecular Plant Pathology

Effect of Sterol Biosynthesis Inhibitors on Phytotoxin (Viridiol) Production by Gliocladium virens in Culture. C. R. Howell, research plant pathologist, Southern Crops Research Laboratory, U.S. Department of Agriculture, Agricultural Research Service, Route 5, Box 805, College Station, TX 77845; R. D. Stipanovic, research chemist, Southern Crops Research Laboratory, U.S. Department of Agriculture, Agricultural Research Service, Route 5, Box 805, College Station, TX 77845. Phytopathology 84:969-972. Accepted for publication 5 June 1994. This article is in the public domain and not copyrightable. It may be freely reprinted with customary crediting of the source. The American Phytopathological Society, 1994. DOI: 10.1094/Phyto-84-969.

The steroid phytotoxin viridiol produced by Gliocladium virens is a major limiting factor in the amount of G. virens-millet preparation that can be used on cottonseed to control damping-off incited by Rhizoctonia solani and Pythium ultimum. Treatment of developing G. virens cultures with 1 νg ml^–1 of the sterol production inhibitors propiconazole or flusilazole and 1–4 νg ml^–1 of myclobutanil or triadimenol suppressed viridiol production without significant adverse effect on the growth of G. virens or on the biosynthesis of the nonsteroid antibiotics gliotoxin and gliovirin. Greater amounts of the antibiotic-producing biocontrol preparation can thus be used to treat seed without concomitant phytotoxic effects on the emerging seedling radicle.