EFFICACY OF TALAROMYCES-FLAVUS ALONE OR IN COMBINATION WITH OTHER ANTAGONISTS IN CONTROLLING VERTICILLIUM-DAHLIAE IN GROWTH CHAMBER EXPERIMENTS

Talaromyces flavus reduced viability of microsclerotia of Verticillium dahliae on senescent potato stems collected from the field when appli ed as ascospores in carboxymethylcellulose or in talcum powder. Incorp orating an alginate wheat-bran preparation of T. flavis in soil at a r ate of 0.5% (w/w) was followed by a decrease of > 90% of the populatio n of V. dahliae in soil at both 15 and 25 degrees C. Population densit ies of V. dahliae were negatively correlated (r = -0.50; P = 0.001) wi th those of T. flavus. However, the population of V. dahliae was also reduced in soil with alginate wheat-bran alone. When incorporated in s oil in alginate wheat-bran and simultaneously coated on seeds in talcu m powder, T, flavus reduced colonization of roots and infection of egg plants by V. dahliae. Although to a lesser extent than with the antago nist, alginate wheat-bran without T. flavus also reduced infection by the pathogen. Treatment with combinations of T. flavus with other bioc ontrol agents, viz. Bacilius subtilis, Fusarium oxysporum or Gliocladi um roseum, containing half of the inoculum of the single application o f each antagonist, gave similar control of root colonization and stem infection by V. dahliae as application of the single antagonists. Popu lation densities on the root of each antagonist were not or only sligh tly affected by the presence of the co-inoculated antagonist suggestin g that the combinations were compatible.