ANTAGONISTIC ACTION OF TALAROMYCES FLAVUS AND TRICHODERMA VIRIDE AGAINST VERTICILLIUM ALBO-ATRUM ON HOPS

Authors: SOLARSKA, EWA - JASTOW POLAND; Fravel, Deborah; PIETR, S - JASTOW POLAND

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 11/23/1999
Publication Date: N/A
Citation: N/A

Interpretive Summary: Verticillium wilt diseases cause severe economic losses on a wide variety of plants. This research was undertaken to evaluate the potential of two beneficial fungi for control of Verticillium wilt of hops. Experiments were conducted in pots containing nonsterile field soil with or without V. albo-atrum grown on wheat straw. Soils were not amended or amended with 2.5 oz of the biocontrol fungus T. flavus grown on wheat bran one week prior to planting or at planting. Pots were maintained outside and the number of plants with wilt symptoms was recorded monthly. Five months after planting, plants were removed and plant weight and browning of the vascular system were recorded. An identical experiment was conducted using T. viride. T. flavus significantly reduced the number of plants with vascular browning when T. flavus and V. albo-atrum were both incorporated one week before planting, but not when the fungi were added simultaneously with the pathogen at planting. Despite the increase in the soil population of T. flavus, T. flavus had no effect on plant weight or the population of V. albo-atrum in soil. Addition of T. flavus one week before planting significantly increased plant dry weight compared to the V. albo-atrum alone and V. albo-atrum + T. flavus added at planting treatments, and resulted in plant dry weight which was comparable to that of the nontreated control. Wilt did not develop in the test using T. viride, and T. viride could not be evaluated for biocontrol. However, T. viride did cause a growth promotion and dry weight for plants treated with T. viride was almost twice as large than in untreated control. This information will be used by scientists developing alternative control measures for management of Verticillium wilt diseases.

Technical Abstract: The biocontrol fungi Talaromyces flavus and Trichoderma viride were evaluated for control of Verticillium wilt of hops. Experiments were conducted in 8 liter pots containing nonsterile field soil infested or not infested with Verticillium albo-atrum grown on wheat straw. Soils were not amended or amended with 75 ml of the biocontrol fungus T. flavus grown on wheat bran one week prior to planting or at planting rooted cuttings of hops. Pots were maintained outside and disease incidence was recorded monthly. Five months after planting, plants were removed and plant weight and vascular browning were recorded. An identical experiment was conducted using T. viride instead of T. flavus. T. flavus significantly reduced wilt incidence, as determined by the presence of vascular browning, when both fungi were incorporated one week before planting, but not when the fungi were added simultaneously with the pathogen at planting. Despite the increase in the soil population of T. flavus, T. flavus had no effect on plant weight, or population of V. albo-atrum in soil. Addition of T. flavus one week before planting significantly increased plant dry weight compared to the V. albo-atrum alone and V. albo-atrum + T. flavus added at planting treatments, and resulted in plant dry weight which was comparable to that of the nontreated control. Wilt did not develop in the test using T. viride, and T. viride could not be evaluated for biocontrol. However, T. viride did cause a growth promotion and dry weight for plants treated with T. viride was almost twice as large than in untreated control.