Efficacy of Talaromyces flavus alone or in combination with other antagonists in controlling Verticillium dahliae in growth chamber experiments

Abstract

Talaromyces flavus reduced viability of microsclerotia of Verticillium dahliae on senescent potato stems collected from the field when applied as ascospores in carboxymethylcellulose or in talcum powder. Incorporating an alginate wheat-bran preparation of T. flavus in soil at a rate of 0.5% (w/w) was followed by a decrease of >90% of the population of V. dahliae in soil both 15 and 25°C. Population densities of V. dahliae were negatively correlated (r= -0.50; P = 0.001) with those of T. flavus. However, the population of V. dahliae was also reduced in soil with alginate wheat-bran alone. When incorporated in soil in alginate wheat-bran and simultaneously coated on seeds in talcum powder, T. flavus reduced colonization of roots and infection of eggplants by V. dahliae. Although to a lesser extent than with the antagonist, alginate wheat-bran without T. flavus also reduced infection by the pathogen. Treatment with combinations of T. flavus with other biocontrol agents, viz. Bacillus subtilis, Fusarium oxysporum or Gliocladium roseum, containing half of the inoculum of the single application of each antagonist, gave similar control of root colonization and stem infection by V. dahliae as application of the single antagonists. Population densities on the root of each antagonist were not or only slightly affected by the presence of the co-inoculated antagonist suggesting that the combinations were compatible.