大豆花叶病的流行因素及综合防治

1985年设置流行观察圃,以4个品种、4种播期、两种种子传毒率的种子,系统观察各因素对病害流行的作用。另设综合防治田,品种与观察圃相同;采取隔离种植、种传率低、适期播种及早期拔除病苗等措施。1986年用相同的4个品种,设5个隔离试区,各播种不同种传率(0—33％)的种子,测定播种种子传毒率对流行的影响。结果证明:传毒种子是当地最主要的侵染来源,田间杂草不传病,蚜虫传播距离多在100米以内,花期以后被侵染的植株,其种传率显著降低。播种种子传毒率与田间流行程度及收获种子传毒率相关显著。所用防病措施效果明显,可控制田间病情指数为4％、种传率为0％、种子斑驳率低于4％。

THE EPIDEMIOLOGY AND INTEGRATED CONTROL OF SOYBEAN MOSAIC VIRUS

An Epidemiological experimental plot involving 4 susceptible soybean cultivars, 4 sowing dates and two sets of seed with comparatively high seed transmission rates, was established for comparing the effects of some factors upon disease epidemics in 1985. Another integrated control plot was located isolately (100 M apart) from other soybean fields with the same cultivars but low seed transmission rates, and roguing infected seedling during early stages The disease incidences and vector populations of two plots were surveyed through the whole growing seasons.In 1986 the same cultivars with 5 different seed transmission rates(0-33%) were planted in 5 isolated plots. The results of field experiments of two years indicated that infected seedlings emerged from diseased seeds were the most important sources of the. disease. No weed host was found, Spreading distances by vectors fell mostly within 100 M. Mants infected after flowering stage produced seeds with very low transmission rates. The relationship between transmission rates of planting and harvested seeds and the degree of the epidemic were highly significant. The mosaic virus was successfully controlled by integrated measures:the disease index was decreased to 4%, seed transmission-0% and seed coat mottling rate-below 4%.