Cultivation of lilies in containers was conducted on a farm-wide scale in Tokushima prefecture using two types of cedar bark medium to evaluate the effects of continuous and renewed treatment on the fungal community structures and chemical properties of these media. The fungal community monitored using denaturing gel gradient electrophoresis (DGGE) was different in both types throughout continuous cultivation and was more affected by type of medium than by cultivation times or season. The chemical properties of cedar bark medium were changed by cultivation management and contributed to differences between the fungal communities. There were no disease symptoms throughout the cultivation period using either continuous or renewed treatment on a small scale, and continuous cultivation was performed three times with few troubles on a farm-wide scale. Hereafter, it is necessary to confirm whether the continuous cultivation of lily is possible more than four times on a farm-wide scale.
愛媛県のアスパラガス産地で改植後に多発する生育障害には,疫病菌(Phytophthora nicotianae)が関与していた。現地の採取土壌からは,疫病菌の特徴を示す無隔壁菌糸と乳頭突起が明瞭な遊走子のうが観察され,各器官の形態的特徴からP. nicotianae van Breda de Haan (1896)と同定した。アスパラガス幼苗を用いた生物検定で,非滅菌区で株枯症状が多発したが,薬剤処理区(メタラキシル粒剤2土壌処理)とオートクレーブ滅菌処理で著しく抑制された。PCR-DGGE法により,移植3日目からアスパラガス幼苗の根圏土壌中で疫病菌の密度が高まることが明らかとなった。