BIOLOGICAL-CONTROL OF FUSARIUM CROWN AND ROOT-ROT OF TOMATO IN FLORIDA USING TRICHODERMA-HARZIANUM AND GLOMUS INTRARADICES

Field experiments were conducted to evaluate commercial formulations of two beneficial fungi, Trichoderma harzianum and Glomus intraradices, for the control of Fusarium crown and root rot of tomato, caused by Fusarium oxysporum f. sp. radicis-lycopersici. Tomato seeds cv. ''Sunny'' were planted into soil nonamended or amended with the biocontrol agents, the former treatment serving as the control. After 6-7 weeks, plants were transplanted into beds fumigated with methyl bromide-chloropicrin in commercial tomato fields with a previous history of Fusarium crown and root rot. Disease incidence and severity were recorded at harvest maturity. Large and extra-large fruits ( greater than or equal to 6.27 cm) also were harvested, counted, and weighed at maturity. Total marketable fruit yield was also determined, Compared to the controls, significant decreases in disease incidence were obtained with treatments of T. harzianum (1993), G. intraradices (1991), and T. harzianum + G. intraradices (both years). Significant decreases in disease severity were obtained with the treatments of T. harzianum (1993), G. intraradices (1991), and T. harzianum + G. intraradices (1993), Yields of large and extra-large fruit or total marketable yield were not significantly different over the controls. These data suggest that commercial biological control agents may be effective in reducing Fusarium crown and root rot and that further evaluation of these agents is justified. (C) 1995 Academic Press, Inc.