PROBLEM TO BE SOLVED: To provide an antiproliferative agent of Raffaelea quercivora that can effectively prevent propagation or proliferation of not only Raffaelea quercivora which is brought into by a noxious insect having invaded into a hole formed in a trunk of a tree and exists in the hole but also Raffaelea quercivora that has come to exist in the tree through tracheas from the hole, and a method for preventing withering of a Japanese oak that can effectively prevent mass withering in a forest using the proliferation-preventing agent of Raffaelea quercivora.SOLUTION: The antiproliferative agent of Raffaelea quercivora includes a sterol biosynthesis inhibitor. The use method thereof is also provided. The sterol synthesis inhibitor is composed of at least one selected from the group consisting of triforine, bitertal, fenbuconazole, cyclobutanyl, tebuconazole and tetraconazole.COPYRIGHT: (C)2009,JPO&INPIT【課題】樹幹に形成された穿孔内に進入した害虫により持ち込まれて前記穿孔内に存在するナラ菌のみならず、穿孔内から導管を通って樹木中に存在するに到ったナラ菌の繁殖乃至増殖を有効に防止することのできるナラ菌増殖防止剤、及びこのナラ菌増殖防止剤を含有し、森林における前記集団枯損を有効に防止することのできるナラ枯れ防止方法を提供すること。【解決手段】ステロール生合成阻害剤を含有することを特徴とするナラ菌増殖防止剤及びその使用方法。【選択図】なし
