东北春小麦丛矮病流行规律研究

STUDIES ON THE EPIDEMIC OF WHEAT ROSETTE STUNT IN SPRING WHEAT IN NORTHEAST CHINA

1993年通过重病区的系统调查和流行因素定量测定,明确灰飞虱是小麦丛矮病最主要的介体,占飞虱种群的95％以上。灰飞虱在呼盟地区1年发生3代,在麦茬、草根、土缝内越冬,老熟带毒若虫和成虫是次年主要的初侵染源,其数量和带毒率与小麦丛矮病发病率之间具有线性关系,回归分析求得如下关系式:Y=0.1823X_1-5.7418X_2-0.03099X_3+1.1404X_4。病情与小麦受侵染时期密切相关,田间试验证明,三叶期以前感染小麦丛矮病发病最重,病情指数可达20％～30％。

Systematic field survey and the quantitative analysis of epidemiological factors indicated that Laodelphax striatellus was the major vector of rosette stunt in wheat and it made up 95% of planthopper population. There were three generations in Hulun-beir Prefecture within a year. The most important primary infection source was virulif-erous nymphs overwintered in underground wheat stub, roots of weed and crack of soil. It showed linear relationship between the amount and the viruliferous rate of the vector and the incidence of wheat rosette stunt. The equation was established by stepwise regression analysis : Y = 0. 1823Xi -5. 7418X2-0. 03099X3-r-l. 1404X4, where X, is the number of overwintering adult vector per 0. 66m2; X2 is viruliferous rate of adult vector; X3 is Xi X2 and X4 is Xf. The disease incidence and the growth stage of wheat during infection were closely related. The most damaging inoculating period was before three-leaf stage. Disease index may reach 20%-30%.