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1976—1977年河北晋县贺家寨大队小麦春季灰飞虱的传带病毒率为31—52%,不同地块同代灰飞虱的带毒率异差较大:而秋苗期则为12—35.4%,其中不同地块上同代(四代成虫)灰飞虱的带毒率的差异从33.3%至35.4%则不太大。灰飞虱的有效传毒指数(即虫口数×自然带毒率)同田间小麦发病率的相关性是非常显著的,其r=0.9769。1975—1976两年调查及计算分析结果,其直线回归公式如y=4.12x-2.577。在有效传毒指数0.7—20.9之间用于予测发病率有效。人工分期侵染试验证明小麦在生长发育过程中受侵愈早,病情愈重,其中死株率也愈大。秋季侵染的死株率达95.6%,病指为99.6;夏季侵染的死株率为0,病指为57.6。秋季小麦出苗前后的大量虫口形成小麦10月中下旬的一个发病高峰,第二年春季4月中旬的虫口高峰形成5月上旬的一个发病高峰。3月下旬的一个发病高峰是越冬前受侵的。病毒在小麦植株中的潜育期的长短随小麦的生长速度而异。温度不过其中因素之一,最短5—8天,最长30—40天。侵染后如小麦进入越冬期,即不表现症状,一直要到返青以后。介体灰飞虱在河北晋县以第五代3—4龄若虫在冬麦地及草荒中越冬。夏季在玉米上可以产卵并孵化,但不能长期存活,主要在地头沟边及夏作物荫蔽下的禾草上越夏。冬麦治虫防病的重点应在秋季麦苗出土前,春季则应在3月中旬左右。冬麦适当推迟播种有利于减少发病率。棉间作麦比平作的病情重六倍而粮麦间作的病情比平作的重九倍。
In 1976-1977, Hebei Province, Hebei Province, Hejiazhai brigade wheat Laodelphax striatellus virus carrying rate of 31-52%, different sites with the same generation of Laodelphax striatellus virulence greater difference: the autumn seedling was 12-35.4%, among which the difference in the virulence rates of Laodelphax striatellus in different plots from 33.3% to 35.4% was not too great. The correlation between the effective transmission index of Laodelphax striatellus (ie, the number of insect population × the natural virulence rate) and the incidence of wheat in the field was very significant. The r = 0.9769.1975-1976 was investigated and calculated in two years. The linear regression The formula is y = 4.12x-2.577. In the effective transmission index 0.7-20.9 for the predicted incidence rate is valid. Artificial staging infection test proved that wheat in the process of growth and development earlier invasion, the more serious the disease, of which the dead rate is also greater. The rate of dead strains in autumn infection was 95.6% and the disease index was 99.6. The dead strain rate in summer was 0, and the disease index was 57.6. A large number of poplar before and after the emergence of autumn wheat formed a peak incidence in late October, the second spring peak of the population in mid-April formed a peak in early May. A peak incidence in late March is pre-wintering invasion. The duration of the latent period of the virus in wheat plants varies with the growth rate of the wheat. However, one of the factors of temperature, the shortest 5-8 days, the longest 30-40 days. Infected wheat, such as winter, that does not show symptoms, has been to return after the green. Laodelphax striatellus in Jinxian County, Hebei Province in the fifth generation of the third instar nymphs in the winter wheat fields and grassland winter. Summer can spawn and hatch on corn, but can not survive long term, mainly in the ditch and ditch under summer shade grass on the summer. Winter wheat pest control disease focus should be in the autumn before the wheat germination, spring should be around mid-March. Appropriate postponement of winter wheat sowing is conducive to reducing the incidence. Cotton intercropping for the condition of wheat than six times heavier than the intercropping of grain and graining than the weight of nine times.