Biological Control of Tomato Verticillium Wilt Disease by Talaromyces Flavus

Abstract

In this study, Talaromyces flavus a fungal antagonist, was isolated from soil samples collected from tomato fields in Tehran and the Western Azarbayjan provinces of Iran. Antagonistic effects of T. flavus isolates against Verticillium albo-atrum (V. a.-a.), the caus- al agent of tomato wilt disease were investigated under laboratory and greenhouse conditions. Soil samples from tomato fields in the Varamin and Uremia regions of Tehran and the Western Azarbayjan provinces respectively, were cultured on selective medium. T. fla- vus colonies were recovered after three weeks. In the laboratory experiments, antagonistic effects of volatile and non-volatile extracts of T. flavus isolates on V. a.-a. growth were investigated. Among isolates, five that caused higher growth inhibition of V. a.-a. were selected for greenhouse experiments. In the greenhouse, first inoculum of V. a.-a. and treatments affected by T. flavus isolates were prepared. For comparison of the infection index in treatments, the greenhouse experiment was performed with a split plot arranged in a ran- domized complete block design with four replications. Result of greenhouse experiments on different types of T. flavus treatments indicated that there was no significant difference among them. However, among five T. flavus isolates, the most effective one was Tf-To-V-24 and Tf-To-U-36. In the experiment on the interaction between different T. flavus treatments and T. flavus isolates, a mini- mum infection index was observed when both soil and seed were treated with Tf-To-V-31. The overall results of this study show that it may be possible to manage tomato Verticillium wilt disease effectively by T. flavus.