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松苗灰霉病一般发生在落叶松播种育苗或留床育苗。当播种育苗每平方米在六、七百株以上时,极易发生。其原因主要是单位面积苗木株数过多,密度大,不易通风透气,给病菌以感染机会。故在苗木过密的地方或死簇苗木形成白色蜘蛛网状物,互相交织,缠绕苗茎,使苗木下部针叶出现白色粘粘糊糊丝状物,针叶霉烂、脱落,死亡。而且相互感染。面积扩大,直至大批死苗。
Pine seedlings gray mold generally occurs in larch sowing seedlings or bed nursery. When sowing seedlings per square meter in more than six, seven hundred or more, can easily occur. The main reason is that the number of seedlings per unit area is too large, dense, not ventilated, to the bacteria to infection opportunities. Therefore, the seedlings densely populated or dead clusters of spider web formation of white spider, intertwined, wound seedlings stems so that the lower part of seedlings sticky white sticky filament, needle mold rotten, fall off, death. And mutual infection. Area expanded until a large number of dead seedlings.