Ability of Talaromyces flavus to occupy the rhizosphere and its interaction with Verticillium dahliae

The ability of Talaromyces flavus to occupy the rhizosphere of potato, cotton and eggplant and to reduce germinability of Verticillium dahliae microsclerotia (ms) was investigated. After 2 weeks the germination of microsclerotia of V. dahliae exposed to T. flavus-infested soil was 32–41% less than those exposed to soil that was not infested, depending on the soil type. With a new medium selective for T. flavus, TF medium, it was possible to monitor the populations of T. flavus in rhizosphere and non-rhizosphere soils. Significantly higher populations of T. flavus were found in rhizosphere soils than in non-rhizosphere soils of each of the test plants when T. flavus was applied as an ascospore drench to soil planted to potato, cotton or eggplant. The reduction of viable V. dahliae microsclerotia and the increase in T. flavus populations in rhizosphere soils may explain how T. flavus reduces Verticillium wilt of eggplant; further, it suggests the feasibility of testing the antagonist against V. dahliae on potato and cotton.