【摘要】 采用定点定期采样、调查、测定的方法，研究了紫苜蓿褐斑病的发生危害的程度及发病条件。结果表明；呼伦贝尔盟紫苜蓿褐斑病的发病日期与病情指数间呈显著正相关（R＝0．9041，N＝11）。在苜蓿与禾草混播的草地，每平方米内苜蓿的枝条数与病情指数间呈显著的正相关（R＝0．7781，N＝10）；病情指数与茎叶比也呈显著的正相关（R＝0．9076，N＝6）；病情指数与单枝叶片数呈显著的负相关（R＝－0．7805，N＝10）。更多还原

【Abstract】 This paper studied the density and the condation of Pseudopeziza medicaginis (Clib) Sacc with the method of sampling, investigation and measurement in definite spots and times. The results showed that: There are significantly positive correlation between the disease index and the disease date (25, July was zero, r = 0. 9041, n = 11), between the disease index and the quantity of branches of alfalfa per m2 (r = 0. 778, n = 10 )and between the disease index and the ratio of stems and leaves of alfalfa (r=0. 9076 , n = 6 ). The correlation between disease index and the number of leaves in each stick is significantly negative (r=-0. 7805, n=10).更多还原