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我国东北地区落叶松人工林发生的传染性枯梢病,是由落叶松球座菌[Guiqnardia laricina (Sawada)Yamamoto et K.Ito]侵染所致,无性阶段为大茎点属(Macrophoma)。接种试验证明该菌通过伤口侵入寄主,潜育期11—15天。兴安落叶松、长白落叶松、海林落叶松、华北落叶松、朝鲜落叶松都易感病,日本落叶松发病较轻。病菌以菌丝、分生孢子器和未成熟的子囊座越冬,以分生孢子和子囊孢子为初次侵染源。子囊座和分生孢子器在降雨后吸水释放孢子,然后借风传播或雨水反溅和冲洗传播。病菌孢子萌发的最适温度为25—27℃。病菌菌丝可在多种培养基上,在散光和在温度25-27℃或室内16—25℃变温条件下,均能产生分生孢子器和分生孢子,但在散光变温条件下以酵母可溶淀粉琼脂培养基和玉米粉蔗糖琼脂培养基产孢最多。病害在7月上旬开始发病,7月中、下旬为发病高峰。多雨高温天气蔓延最快,林缘冲风地带和7—15年生的落叶松人工林发病重。
Infection in the larch plantation in Northeast China is caused by the infection of Guiqnardia laricina (Sawada) Yamamoto et K.Ito, and the vegetative stage is Macrophoma. Inoculation test proved that the bacteria invaded the host through the wound, the incubation period of 11-15 days. Larix gmelinii, Larix sibirica, Larix kaempferolum, Larix principis-rupprechtii, Korean larch are susceptible to disease, Japanese larch less incidence. Pathogenic bacteria in mycelium, conidia and immature sarcoplasmic overwinter, with conidia and ascospores as the primary source of infection. Bursa and conidia absorb water after the release of spores, and then spread by wind or rain spill and wash spread. Germination of bacteria spores the optimum temperature of 25-27 ℃. Bacteria mycelium can be in a variety of media, astigmatism and in the temperature 25-27 ℃ or indoor temperature conditions 16-25 ℃, can produce conidia and conidia, but under the conditions of astigmatism yeast Soluble starch agar medium and corn flour sucrose agar medium most sporulation. Disease onset in early July, mid-July, late onset peak. Rainy and hot weather spread the fastest, the rim of the edge of the wind and 7-15 years old larch plantation incidence.