当归麻口病的研究

 当归麻口病是我省当归产区区要病害之一,也是国内外未曾报道的一种新病害。1986、1987年调查研究表明,我省凡当归栽培区均有发生,田间发病率84.9%,病情指数56.4%,重病地高达100%。主要症状是归根表皮呈黄褐色纵裂,毛根增多并畸化,严重时皮层组织呈干烂,糠腐状。
从罹病归根皮层内外分离出线虫、真菌、细菌,分别进行人工接种健归苗并再分离发病归根,证实当归麻口病系线虫危害所致,其病原线虫为腐烂茎线虫(Ditylenchus destructor)。
经系统检测种苗不带线虫。病土和病残组织为初侵染源,腐烂茎线虫主要分布在0-10cm土层内,在当归整个生育期内线虫都可侵入,但以前期侵害为主,该线虫在当地一年可发生6-7代,以成虫在土壤和病残组织内越冬。

ON THE CAUSAL NEIMATODE OF ANGELICA “MAKOUBING” DISEASE AND ITS CONTROL

The "Makoubing" of the Chinese angelica is one of the important disease in its grown areas. This disease is new to the world. The investigations macie during 1986-1987 showed that it occurred throughout all the grown areas. The incidence of the disease in the fields was 84.9% with the disease index 56.4 and even up to 100 in certain seriously infected areas. The main symptoms of the disease are yellowbrown vertical splitting of the root epidermis, proliferation and malformation of root hairs.When the disease is extremely serious, the ppidermic tissues begin to rot and looks as if they were dry decayed chuff.
The nematodes, fungi and bacteria isolated from the infected root were inoculated separately, and finally confirmed that the disease was caused by the nematode, Ditylenchus destructor.
Systematic examinations indicated that the seedlings were free from the nematodes. The initial source of the disease was the infected soil and tissues. The nematodes were distributed in the top soil layer at 0-10cm.They can infect and cause development of the disease during the entire growing period, especially at the first stage. The nematodes reproduce 6-7 generations a year, and hibernate as adults and larvas in the soil and residual infected tissues.