Effect of five fungicides with different modes of action on cobweb disease (Cladobotryum mycophilum) and mushroom yield

Abstract

The fungicides chlorothalonil, metrafenone, prochloraz-Mn, thiabendazole and thiophanate-methyl were tested in vitro and in vivo for their effect on Cladobotryum mycophilum, the mycoparasite that causes cobweb disease in white button mushroom. In vitro experiments showed that metrafenone (EC 50 = 0.025 mg L −1 ) and prochloraz-Mn (EC 50 = 0.045 mg L −1 ) were the most effective fungicides for inhibiting the mycelial growth of C. mycophilum. Selectivity indexes of the tested fungicides on both C. mycophilum and Agaricus bisporus indicated that metrafenone was also the most selective fungicide, while chlorothalonil was the most toxic fungicide against A. bisporus mycelium. The in vivo efficacy of fungicides for controlling cobweb was evaluated in three mushroom cropping trials, which were artificially inoculated with C. mycophilum (10 6 conidia m −2 ). Prochloraz-Mn provided good control, although the surface colonised by cobweb reached 12% by the end of the crop cycles. None of the inoculated cropping trials treated with metrafenone showed any cobweb disease symptoms, and neither were any significant phytotoxic effects on mushroom yield recorded. These results indicated that metrafenone can be used as an alternative to prochloraz-Mn in the control of cobweb disease.

Screening and Evaluation of Essential Oils from Mediterranean Aromatic Plants against the Mushroom Cobweb Disease, Cladobotryum mycophilum

“…The T. vulgaris (IEO3B, IEO3A) and S. montana (IEO1A) EOs treatments, at 1% concentration, were as effective as those involving metrafenone. Until now, the most effective treatment for controlling cobweb disease has been with metrafenone [13]. These results agree with those of previous studies carried out in mushroom growing rooms, which showed that the preventative use of T. vulgaris oil was able to control the development of wet bubble disease caused by Mycogone perniciosa in mushrooms with no detrimental effect on the growth of A. bisporus, and provided an overall yield similar to that following the application of a commercial fungicide [20].…”

“…These values (lower than 0.1) are better than those obtained in previous studies with the fungicides chlorothalonil and thiophanate-methyl (SI = 0.38 and 0.21, respectively). However, the fungicides metrafenone, prochloraz-Mn, and thiabendazole showed better selectivity than the EOs tested (SI = 0.00001, 0.0031, and 0.01, respectively) [13]. On the other hand, L. x intermedia and T. mastichina EOs had the greatest inhibitory effect against the A. bisporus mycelium, and their selectivity indexes were the highest ( Table 3).…”

“…The antifungal activities of the EOs against C. mycophilum and A. bisporus were calculated by in vitro sensitivity assays, with slight modifications [8,13]. The five EOs (containing 0.01% Tween 20) from each plant sample were added to molten sterile malt extract agar (MEA) medium at 45 • C prior to solidification.…”

“…The pathogen may grow over primordia and mushrooms, affecting the salability of the product [10]. Methods to control cobweb include strict hygiene measures to prevent dispersion of the conidia and the application of fungicides, mainly prochloraz and metrafenone [11][12][13]. However, the use of conventional chemical fungicides is gradually being limited due to its negative effects on human health, environmental safety, pathogen resistance, etc.…”

Growing edible mushrooms: a conversation between bacteria and fungi

“…The control of mushroom pests and diseases therefore currently relies on the application of integrated management programs in addition to the use of chemical pesticides, mostly fungicides . However, an increasing demand for organic products and reports of the emergence of resistant strains (Carrasco et al, 2017) support the case for the development of novel sustainable strategies for mushroom crop protection. In order to reduce fungicide dependence, environmentally friendly biomolecules such as aromatic plant extracts have been tested.…”