Myxomycetes occurring in open-field mushroom cultivation were surveyed in order to elucidate the properties of Myxomycete disease. As a result of the examination, 9 genus 18 strains of Myxomycetes were confirmed at open-field mushroom cultivation sites. We also found fruit-bodies of Myxomycete on the wood blocks of Meripilus giganteus, which was identified as Enteridium lycoperdon. The plasmodia of Myxomycetes which moved against the mushrooms hindered the growth of the fruit-bodies on Meripilus giganteus. Conversely, Fruit-bodies of Grifola frondosa suffered heavy damage by Physarum rigidum, the extent of which increased year by year. Although methods for the prevention of Myxomycete disease against Grifola frondosa have been established, the damage has not been eliminated. However, the number of plasmodia were decreased by disposal of the plasmodia on Physarum rigidum.

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The effects of light illumination on the mycelial growth of Ganoderma lucidum Karst were investigated. A comparative examination of the results obtained under dark conditions and those under light illuminated conditions showed that the mycelial growth rate in the dark was higher than that in the light. When a switch from light to dark conditions had been made, a remarkable increase in mycelial growth rate was observed at 6 days after the light conditions were switched. However, switching from a dark condition to light did not present a marked effect on mycelial growth. When the intensity of light illumination during cultivation was varied between 5 lx and 4,500 lx, the mycelial growth rate at the illumination intensity under 30 lx was the same as that under dark conditions. By increasing the illumination intensity, the growth rates decreased with the intensity up to 70 lx. When light with the wavelength of 351 or 470 nm was applied to the culture, the mycelial growth rates were markedly suppressed, while the growth rates at the wavelength of 630 or 730 nm had decreased to the same degree by illumination with a fluorescent lamp at 1,000 lx. When cultivation was done in the darkness, the maximum value of β-1,3-glucan content of the mycelium was two times higher than the light illuminated culture.

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Nine species of edible mushrooms, commercially available in Japan, Lyophyllum decastes (Hatakeshimeji), Hypsizigus marmoreus (Bunashimeji), Grifola frondosa (Maitake), Flammulina velutipes (Enokitake), Pleurotus ostreatus (Hiratake), Agancus bisporus (Mushroom), Pleurotus eryngii (Eringi), Lentinula edodes (Shiitake, the sawdust substrate cultivation and the crude wood cultivation), Phohota nameko (Nameko) were evaluated for their 2,2-Dipheny1-1-picrylhydrazyl (DPPH), hydroxyl, and superoxide radical scavenging abilities using electron spin resonance (ESR)equipment. The DPPH radical scavenging ability was the largest in Gnfola frondosa and its value was 5.8±0.3mmol equivalent ascorbic acid per g of dry matter (mmol eq.Vc/g). The hydroxyl radical scavenging ability were significant large in both Flammulina velutipes and Grifola frondosa, each value was 38.7±1.8 and 24.4±1.2 mmol eq.Vc/g, respectively. The superoxide radical scavenging ability was the largest in Agaricus bisporus, and the next was Pholiota nameko. The values were 14.8±1.3 and 11.6±0.7 mmol eq.Vc/g, respectively. These results show that the species of radicals scavenged effectively by mushrooms were different dependent on the species of mushroom.

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