【摘要】 小麦根腐病是广东小麦重要病害之一。病原菌在干旱土壤中可存活281天以上,在淹水土壤中80天使死去,“麦→稻→稻”水旱轮作制的地区不存在土壤带菌问题。室外堆放的病秆所带分生孢子可存活281天以上,但菌丝体在220天以前死去,不能产孢传播。室内人工接种有6种作物和11种杂草感病,其中甘蔗、茭白、雀稗、纤毛鸭咀草和川谷为前人所未报道。但大田调查结果,除小麦外迄今未见有自然感病寄主。种子带菌很普遍,是广东小麦根腐病的主要初侵染源。 本试验对Ledingham和Chinn的土壤孢子数估算法作了改进,测定方法简单,较为准确,可供田间孢子量测定之用。更多还原

【Abstract】 The common root rot of wheat caused by Helminthosporium sorokinianum Sacc. et Sorok. (Cochliobolus sativus (Ito et Kurib. ) Drechs. et Dast.) has become one of the important diseases in South China in recent years.The present investigation, carried out in 1980 and 1981 in Guangdong Province,proved that the conidia of the causal fungus remained viable for more than 281 days in dry soil and less than 80 days in water-soaked soil. The soil in the regions where the main cropping system consisted of "wheat-rice-rice" were not infested. Among the 30 species of plants, including crops and weeds, inoculated in the greenhouse, five kinds of crops and eleven species of weeds showed certain degrees of susceptibility,but these susceptible hosts had not been found in the fields. The infected seeds were found to be the main source of primary inoculum.By a comparison of five diffevent metnods of coumting the conidia in the soil, a method modified from Chinn’s "Flotation-Viability Count Metnod" was recommended.更多还原