Volume 19 Part 1 Article 17: Evaluation of bio-fungicides for the control of fungal diseases on Agaricus bisporus

Volume 19 Part 1 Article 17
Year 2016
Title: Evaluation of bio-fungicides for the control of fungal diseases on Agaricus bisporus
Author: David M Beyer, John A Pecchia, and Kimberley Paley

Two prominent fungal pathogens Trichoderma aggressivum and Lecanicillium fungicola currently cause the most widespread diseases, Green Mold and Dry Bubble respectively, of the cultivated Agaricus bisporus mushroom production worldwide. With the decrease in number of registered and effective chemical fungicides available to growers, the industry needs to look for more environmentally friendly alternatives. Cropping experiments were conducted at the Pennsylvania State University Mushroom Research Center to determine if several novel bio-fungicides and essential oils were effective in controlling these fungal pathogens. It has been reported that the degree to which T. aggressivum develops on mushroom grain spawn, following inoculation with T. aggressivum, is positively correlated with disease severity in actual mushroom production trials. Therefore, the extent to which a fungicide protects the spawn from green mold would potentially be predictive of the level of disease control achieved in cropping trials. Commercial spawn of an off-white hybrid mushroom strain was treated with calcium sulphate as the bio-fungicide carrier (control) and a mixture of calcium sulphate and commercially available biological fungicides and compared to synthetic non-grain spawn. Cropping experiments were used to evaluate combinations of Mertect®, Bravo®, JAZZ® and Trilogy® for efficacy against T. aggressivum. L. fungicola was inoculated with a spore suspension several days after casing.

The trials consisted of combinations of un-inoculated and inoculated-untreated controls compared to a treatment of registered chemicals. Different rates of application and combinations of bio-fungicides were tested. The most efficient method and timing for these chemicals is reported here and efficacy was determined by fresh mushroom yields and quantification of diseased mushrooms, both bubbles and spotted mushrooms. Our results suggest that most bio-fungicides tested were not effective against either pathogen. However, a couple of essential oils were effective and a naturally occurring bacterium, Streptomyces griseoviridis, a commercially available biological fungicide was as effective as the registered chemical treatment in reducing L. fungicola disease development.

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