Volume 12 Part 2 Article 77: Development of Verticillium Disease in Pennsylvania Mushroom Crops

Volume 12 Part 2 Article 77
Year 1989
Title: Development of Verticillium Disease in Pennsylvania Mushroom Crops
Authors: V.J. Spadafora, P.J. Wuest and D.L. Rinker

Abstract:

Verticillium fungicola (Preuss) Hassebr. is recognized as one of the most prevalent and important pathogens of the commercial mushroom, Agaricus bisporus (Lange) Imbsch. In Pennsylvania, Forer et al. (1974) isolated the pathogen from 11.3% of mushrooms sampled monthly for 12 months at ten mushroom farms, and estimated crop losses at $ 6.3 million for the state. Rinker and Wuest (1987a) reported the incidence of Verticillium diseases on 1st and 2nd break resulted in significantly reduced yield on 4th break, thus Verticillium disease continues to be an economic threat to Pennsylvania mushroom crop.

There are few reports describing the development of disease over time, despite the importance of Verticillium. Wuest and Harvey (1978) presented data on the increase of disease incidence on three mushroom strains. Rates of disease increase were different for the three strains, indicating a form of nonspecific, or horizontal resistance (sensu Van der Plank, 1963).

Description and classification of disease epidemics in quantitative terms has proven useful with many other agricultural crops. Epidemiological studies have been used to identify host resistance, evaluate experimental treatments, identify disease management strategies, and to develop disease forecasts (Fry, 1982; Kranz, 1974, Madden, 1980). The most well known models of disease development are the monomolecular, (or simple interest) and the logistic, (or compound interest), introduced into the field of plant pathology by Van der Plank (1963). The logistic model is typically applied to diseases, such as Verticillium brown spot and bubble, where secondary inoculum is produced by the pathogen during the growing season.

The objectives of this study were to quantify levels of Verticillium disease incidence and rates of disease increase on commercial mushroom farms in Pennsylvania, and to perform a preliminary investigation on factors that influence disease incidence and rates of disease development.

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