Variations in isolates of Mycogone perniciosa and in disease symptoms in Agaricus bisporus

Abstract

Eight isolates of Mycogone perniciosa, five from Agaricus bisporus and three from Agaricus arvensis, were studied. One isolate of Mycogone rosae was also included. Aleuriospore and phialospore morphology varied among the isolates as did other characteristics, but M. rosae was the only isolate to produce a red colouration of the medium. Growth was also variable, with three isolates of M. pemiciosa growing at about half the rate of the fastest. The slow‐growing isolates contained virus‐like particles, 36 nm diameter, and produced sclerodermoid mushrooms. The fast‐growing isolates did not contain virus‐like particles and caused cap spotting, a symptom not previously described for M. perniciosa. M. rosae produced characteristic cap spots and no scierodermoid mushrooms. A comparison of two isolates of St. perniciosa. one from A. bisporus and one from A arvensis, showed a much greater yield reduction as a result of symptoms caused by the isolate from A. bisporus. The isolate of M. rosae had no significant effect on yield. Restriction fragment banding patterns of ribosomal DNA showed no differences among the seven isolates of M. perniciosa from England, but the isolate from China was slightly different. The single isolate of M. rosae was distinct from M. perniciosa.

Pathogenicity Of Mycogone Perniciosa Isolates Collected On Polish Mushroom Farms

“…Our research concern- ing colony pigmentation on agar medium and pathogenicity of the isolates showed that CBS isolate (a weakly pathogenic against A15 strain of A. bisporus) is characterised with a slow-growing and little pigmented colony, while M9 (strongly pathogenic isolate) and M19 (weakly pathogenic) produced equally brown pigmented colony agar media. Atkey et al (1976) and Fletcher et al (1995) found that all studied isolates were highly pathogenic irrespective of the growth rate and virus particle content. It seems that the virulence in M. perniciosa isolates reveal a complex interaction between genotypes of pathogen and the host.…”

“…Variability in the pathogenicity of M. perniciosa isolates can be attributable to the presence of mycoviruses in hyphae of these isolates (Fletcher et al 1995;Lapierre et al 1971;Umar et al 2000). Umar et al (2000) observed intracellular virus-like particles in scanning electron microscope.…”

“…Umar et al (2000) observed intracellular virus-like particles in scanning electron microscope. Fletcher et al (1995) recorded that virus-containing strains of M. perniciosa grew slower and induced typical symptoms of wet bubble that is, sclerodermoid mushrooms. The fast-growing isolates did not contain virus-like particles and caused only cap spotting.…”

“…Fletcher et al (1995) showed that pathogenic isolates of M. perniciosa are slow-growing on agar and their mycelium is pigmented, because it produces numerous aleuriospores whereas, weakly pathogenic isolates are characterized by fast growth on medium and little pigmented mycelium.…”

Damage potential of Tyrophagus putrescentiae Schrank (Acari: Acaridae) in mushrooms

“…It hampers the yield [75][76].The mycopathogen adheres to and penetrates A. bisporus during any stage of fruiting body development causing either the characteristic undifferentiated lumps of primordia or the fruiting body's color changes to brown. These tumorous bodies are covered with wet bubbles, white and fluffy mycelium, and amber droplets [77][78]. In commercial cultivation, M. perniciosa can commonly causes yield losses of about 15-30 percent once WBD develops.…”