Japanese, Thai and their F₁ hybrid stocks of Pleurotus ostreatus were cultivated at 22°C during the spawn-run time, then at 15°C or 22°C during fruiting. There was no noticeable difference in change of CO₂ concentrations in sawdust-ricebran substrata between Japanese and Thai stocks during spawn-run time. However, Thai stocks fruited and raised CO₂ concentration of the substrata earlier than did Japanese stocks at both temperatures. At 22°C, Thai stocks formed plentiful fruit-body primordia that grew into normal fruit-bodies, while Japanese stocks formed sparse primordia that failed to follow normal growth. These traits of Japanese and Thai stocks segregated in their F₁ hybrid stocks, and many F₁ stocks represented the Thai phenotype.

　Corn fiber, the waste product of corn starch manufacture, was studied to estimate its applicability as a substrate for the commercial production of several edible mushrooms in Japan by bottle cultivation. The use of corn fiber successfully increased the yield of fruit-bodies (fresh weight basis) of Pleurotus ostreatus, P. sajor-caju, Pholiota nameko and Hypsizygus marmoreus by 1.02～1.31 times when it was added to the basal medium (10～30%) consisting of sawdust and rice bran.

　A hyphomycete, Alysidium resinae var. microsporum, newly found on a plastic doll in Japan, is described.

　The effects of culture conditions on the production of volatiles by Lasiodiplodia theobromae were studied. 2-Octeno-δ-lactone was produced in significant yield only in potato-glucose medium by L. theobromae cultured for 14 d. About 0.5 mg was produced by L. theobromae cultured on a plate of the medium (20 mL) in the dark, as noted with fluorescent light. In liquid medium, however, the fungus produced no δ-lactone in the dark, in contrast to the result obtained with light. 2-Octeno-δ-lactone within or on the surface of agar medium covered with L. theobromae was essentially the same, regardless of mycelial content.