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Symptoms of green mould disease on oyster mushroom growing substrate. Extensive green sporulation areas are evident inside the plastic bag, and on wheat straw portions.
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In a mushroom farm located in Emilia-Romagna (north Italy), a drastic reduction of Pleurotus ostreatus (Jacq.) P. Kumm. 1871 yield associated with “green mould disease” was observed. Disease symptoms consisting in dense white mycelium patches, not visually distinguishable from those of P. ostreatus, followed by extensive green sporulation areas, we...
Citations
... Trichoderma species associated with green mold disease have been isolated from both substrates and fruiting bodies of edible mushrooms such as Agaricus bisporus, A. bitorquis, Calocybe indica, Ganoderma lucidum, Lentinus laedodes, Pleurotus eryngii, P. ostreatus, P. sajor-caju, and Volvariella volvacea (Singh et al. 2006;Innocenti and Montanari 2014;Lee et al. 2020). It has been found that Trichoderma pleuroticola and T. pleurotum commonly cause green mold disease on oyster mushrooms whereas T. aggressivum and T. harzianum are the common causal agents on A. bisporus (Hatvani et al. 2012;Błaszczyk et al. 2013). ...
Scientific names are crucial for communicating knowledge concerning fungi and fungus-like organisms. In plant pathology, they link information regarding biology, host range, distribution and potential risk to agriculture and food security. In the past, delimitation among pathogenic taxa was primarily based on morphological characteristics. Due to distinct species sharing overlapping characteristics, the morphological identification of species is often neither straightforward nor reliable. Hence, the phylogenetic species concept based on molecular phylogenetic reconstructions gained importance. The present opinion discusses what a fungal species is and how identification of species in plant pathology has changed over the past decades. In this context, host-specialization and species complexes are discussed. Furthermore, species concepts in plant pathology are examined using case studies from Bipolaris, Colletotrichum, Curvularia, Diaporthe, Diplodia, Meliola, Plasmopara, rust fungi and Trichoderma. Each entry contains a brief introduction to the genus, concepts used in species identification so far and the problems in describing a species followed by recommendations. The importance of correctly naming and identifying a species is addressed in the context of recent introductions, and we also discuss whether the introduction of new species in pathogenic genera has been overestimated. We also provide guidelines to be considered when introducing a new species in a plant pathogenic genus.
... The highest sensitivity to metrafenone was also shown by THSC, followed by T. pleuroticola and T. pleuroti. On the contrary, results of Hatvani et al. [10] and Innocenti and Montanari [36] showed that T. pleuroti and T. pleuroticola were more sensitive to prochloraz than T. harzianum. In addition, Innocenti et al. [34] reported that prochloraz at the highest doses of 0.25 and 1.25 mL mL À1 reduced colony growth rate of Trichoderma strains from oyster mushroom farms with 22.3-100% and 86.7-100%, respectively. ...
Twenty-two strains of Trichoderma spp. (T. harzianum species complex [THSC], Trichoderma aggressivum f. europaeum, Trichoderma pleuroti, and Trichoderma pleuroticola) causing green mold disease on edible mushrooms (button mushroom, shiitake and oyster mushroom), collected during 2004–2018 from four countries (Serbia, North Macedonia, Croatia, and Hungary) were examined. Based on their ITS (internal transcribed spacer) sequences, strains from shiitake mushroom in Serbia were identified as members of the THSC, while in samples obtained from Serbian and North-Macedonian oyster mushroom farms THSC, T. pleuroti and T. pleuroticola were detected, which represent the first findings in the region. In fungicide susceptibility tests, all examined Trichoderma strains were found to be highly sensitive to prochloraz (ED50<0.4 µg mL⁻¹) and considerably susceptible to metrafenone (ED50 < 4 µg mL⁻¹). The most sensitive taxon to both fungicides was THSC from oyster mushroom. The toxicity of metrafenone was satisfying and strains from oyster mushroom showed the highest sensitivity (ED50 < 1.43 µg mL⁻¹), while strains originating from button mushroom and shiitake displayed similar susceptibilities (ED50 < 3.64 µg mL⁻¹). After additional in vivo trials, metrafenone might also be recommended for the control of green mold disease in mushroom farms.
... The disease has also been reported in North America (Sharma & Vijay, 1996). Serious cases of green mould have been detected in P. ostreatus farms in Italy (Woo et al., 2004(Woo et al., , 2009Alfonzo et al., 2008;Innocenti & Montanari, 2014). ...
... Hatvani et al. (2012) identified T. pleuroti and T. pleuroticola as causal agents of the green mould disease from samples obtained from Croatian farms. In the study of Innocenti & Montanari (2014), T. pleuroti and T. pleuroticola were isolated from areas of the cultivation substrate with symptoms, whereas T. harzianum was isolated only from symptomless areas. ...
... Currently only prochloraz is allowed for use in mushroom farms in Italy. The few studies carried out on the sensitivity of T. harzianum, T. pleuroti and T. pleuroticola to fungicides, specifically to prochloraz, showed that T. pleuroti and T. pleuroticola were more sensitive than T. harzianum (Hatvani et al., 2012;Innocenti & Montanari, 2014). ...
The green mould disease causes serious economic losses in Pleurotus ostreatus crop worldwide and also in Italy, where prochloraz is the only chemical fungicide allowed to control the disease. The effectiveness of the doses 0.01, 0.05, 0.25 and 1.25 μL L⁻¹ (field dose) of prochloraz (Sponix Flow, 450 g L⁻¹), against colony growth rate and spore germination of Trichoderma pleuroti, T. pleuroticola and T. guizhouense strains on wheat straw extract agar plates were evaluated. Complete inhibition of Trichoderma pleuroti and T. pleuroticola growth was showed by field dose of prochloraz, and for T. pleuroti also by 0.25 μL L⁻¹. Complete inhibition of spore germination occurred for all Trichoderma strains at field dose, and at 0.25 μL L⁻¹ for T. pleuroti strains. In in vivo assay, the effect of prochloraz doses 0.05, 0.25 and 1.25 μL L⁻¹ on colonisation of straw substrate by T. pleuroti, T. pleuroticola and T. guizhouense inoculated at two spore density (1×10² and 1×10⁵ spores mL⁻¹) immediately after P. ostreatus spawn was studied. Trichoderma pleuroti and T. pleuroticola were both responsible of green mould disease, whereas T. guizhouense was not pathogenic. Trichoderma pleuroti was more aggressive than T. pleuroticola. Prochloraz was effective against T. pleuroti at the field dose, and against T. pleuroticola at 0.25 and 1.25 μL L⁻¹ doses. Our study on Trichoderma–Pleurotus interaction type showed that Trichoderma species were active against the mycelial growth of P. ostreatus by competition for space and nutrients, and neither hyphal interaction nor effect by volatile or non‐volatile metabolites occurred.
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This chapter presents a literature overview about the green mould disease of cultivated mushrooms caused by Trichoderma species, a problem which may result in serious economic damage due to substantial losses of crop yield in mushroom production. The first major green mould epidemic struck the production of white button mushroom (Agaricus bisporus) in Northern Ireland in 1985, but since then, the problem has occurred in a series of further countries. Outbreaks appear to be primarily caused by two subspecies of Trichoderma aggressivum. Trichoderma green mould infection has also been observed in many countries in cultivated oyster mushroom (Pleurotus ostreatus), where the main pathogens have been described as T. pleuroticola and T. pleuroti. Moreover, various further Trichoderma species have been reported to cause green mould problems in the production of shiitake (Lentinula edodes), as well as less frequently produced other mushrooms like Ganoderma species and Cyclocybe aegerita.Components of mushroom cultivation substrata, the air, vehicles, equipment, contaminated clothing and animal vectors are among the potential sources of green mould infections. General symptoms of green mould generally appear in the mushroom cultivation substratum as large, greenish spots, but the causal agents may also colonise the surface of fruiting bodies. Green mould species compete efficiently for nutrients and space in the cultivation substratum; in addition, they produce extracellular enzymes, toxic secondary metabolites and volatile organic compounds that can lead to drastic crop losses.Species-specific primers are now available for the effective monitoring of Agaricus-, Pleurotus- and Lentinula pathogenic Trichoderma species. Control measures include pasteurisation, the use of disinfectants, chemical treatments, biological control by natural products or the use of antagonistic bacteria and fungi, as well as the breeding and cultivation of resistant mushroom cultivars.KeywordsWhite button mushroom
Agaricus bisporus
Shiitake
Lentinula edodes
Oyster mushroom
Pleurotus ostreatus
Ganoderma
Cyclocybe aegerita
Green mould disease
Trichoderma
