灰飞虱传播水稻条纹叶枯病毒的特性

灰飞虱是水稻条纹叶枯病的传毒介体,带毒的长短翅型成虫及各龄若虫均能在秧苗期和分蘖期传毒感病,秧苗感病以卷叶型为主,均相继枯死,分蘖期感病以展叶型为主,病株95％以上不能抽穗结实。主蘖传毒,主蘖及各分蘖均发病,分蘖传毒,仅分蘖发病。带毒雌雄配对繁衍3代,无毒分离率平均为31.38％。带毒虫传毒3min,发病率为2％,传毒2h,发病率达22.5％。带毒率50％以上的群体一生传毒频次为3～5次,10％以下仅1次。各龄若虫及不同成虫1天传毒致病株:秧苗期为0.97株及1.26株:分蘖期为0.45株及0.42株。秧田传毒后,80％以上的隐症病株到本田期才陆续显现病状,故秧田“治虫防病”甚为重要。

CHARACTERISTICS OF LAODELPHAX STRIATELLUS TRANSMIT RICE STRIPE VIRUS

Laodelphax striatellus is the transmit vector of rice stripe virus (RSV). All adults and nymphs of L, striatellus can transmit RSV at seedling and tillering stages. The diseased seedlings present rolling leaf and die one after another. The symptom is unfolding leaf type at early tillering stage. Over 95% diseased plants could not sprout ears nor bear seed. The viruliferous male and female L. striatellus could mate and reproduce for three generations. The average segregation rate of non-virus posterity was about 31. 38%. The rate of the diseased plants was 2% and 22. 5% after fed with the viruliferous L. striatellus for 3 min and 2 h, respectively. The population with a viruliferous L. striatellus rate of 50% could transmit virus for 3 - 5 times per generation while it was only once if the rate of viruliferous L. striatellus was below 10%. The nymphs could transmit 0. 97 and 0. 45 plants per day at the seedling and tillering stages,respectively. The adults, however, could transmit 1. 26 and 0. 42 plants per day at the corresponding periods. More than 80% of diseased seedlings showed symptoms gradually after they were transplanted into the fields if they were affected by L. striatellus in seedling beds. Therefore, it is important to control L. striatellus to prevent rice from RSV in seedling beds.