in 2013 , specimens were collected from a shiitake cultivation farm , located beside high mountains in geochang - gun , gyeongnam province , korea . slime mold fruiting bodies developed on the top and side surfaces of the oak logs , a year after being cut . the bark of infected oak logs came off easily , exposing the sapwood beneath ( fig . 1a , 1b , and 1c ) . fruiting bodies formed close , profuse , large colonies and mature sporangia appeared brown , cylindrical , 10 to 15 mm tall with dark reddish - brown spore - masses ( fig . 1d ) . after removing the spores , the sporangium appeared bright brown ( fig . the sporophore morphology , surface structures of sporangia , columella , capillitium , peridium , spores , stalk , and hypothallus of the slime mold samples were assessed through stereomicroscopy and light microscopy . the stalk appeared black , shiny , and slender , measuring 1.0~4.0  0.1 mm to 0.2 mm . primary branches extended from junctions within the net and at distant intervals from the columella , simple at first , then suddenly branching vigorously to form a smooth surface net with rounded or angular mesh forms measuring 20~70 m in width ( fig . the columella was black , reaching almost to the top of the sporotheca , tapered , rigid , and flexuous towards the tip ( fig . 2c ) . spores were lilac - brown , 7~9 m in diameter , almost smooth with fine , pale warts ( fig . for in vitro culture , moist chambers consisting of a sealed sterilized plastic box with three sheets of kim 's towel at the bottom . spore masses and fruiting bodies were transferred to the plastic box and incubated at room temperature ( 25~28 ) . 3b ) . based on morphological characteristics , the pathogenic slime mold causing decay of the oak bark was identified as stemonitis splendens rostaf , as reported by nieves - rivera and stephenson .
severe bark decay disease was observed on oak logs at a shiitake cultivation farm in geochang - gun , gyeongnam province . 
 the symptoms observed were fruiting bodies that had developed on the top and side surface of oak logs . as a result , 
 the bark came off easily exposing the sapwood . 
 slime mold specimens collected from oak logs showed developing fruiting bodies comprising of stalks , hypothallus , capillitium , and columella , and the causal agent of bark decay disease was identified as stemonitis splendens on the basis of morphological characteristics . to our knowledge , this is the first report of stemonitis splendens causing bark decay of oak logs used for shiitake mushroom cultivation in korea .