白背飞虱对南方水稻黑条矮缩病传毒效率的影响

Effects of White-backed Planthopper,Sogatella furcifera,Horvath on Transmission Rates of Southern Rice Black Streaked Dwarf Virus

为完善水稻对南方水稻黑条矮缩病抗性的评价方法提供理论依据，运用RT—PCR检测法及其他常规方法研究不同虫态、不同接虫密度对白背飞虱传播SRBSDV的能力、不同水稻生育期对白背飞虱传毒效率影响、自背飞虱饲毒时间和传毒时间对南方水稻黑条矮缩病发病率的影响。结果表明，同一虫态白背飞虱不同的接虫密度水稻发病率不同，接虫密度增加发病率增高；随着虫龄增大而白背飞虱传毒效率增高。接虫密度2头／苗、3头／苗时，4～5龄和长、短白背飞虱型成虫传毒引起水稻发病率均达到100．00％。不同水稻生育期影响白背飞虱传毒效率。接虫后，1叶期至30d苗龄水稻发病率均为100．00％，40、50、60和70d苗龄水稻发病率依次为91．30％、4．17％、0．00％和0．00％。随着白背飞虱饲毒时间或传毒时间加长，水稻发病率会不断增高。当自背飞虱饲毒时间为60．18h或传毒时间为26．34h时，水稻发病率均达到100．00％。因此，进行水稻品种抗SRBSDV人工接种鉴定时，传毒介体白背飞虱饲毒时间不应低于60．18h，待测苗20～25d苗龄时接虫，接虫密度为每苗接2头带毒4～5龄若虫或成虫，传毒时间不应低于26．34h。建议对现有的抗白背飞虱水稻品种（材料）进行抗SRBSDV鉴定，从中发掘抗病材料，为水稻抗性育种工作者选择提供抗源材料。

In order to provide a theoretical basis for improving the evaluation method on rice resistance to Southern rice black streaked dwarf virus （SRBSDV）, the effects of different life-stages, different insect density and different rice growth stages on the SRBSDV transmission ef- ficiency of WBPH, and the viral acquisition periods and the effect of the viral inoculation time of WBPH on the incidence rate of rice were studied, using the RT-PCR method and other conventional methods. The results showed that different insect density could cause different in- fected rates of rice when WBPH was at the same life-stage. The rice infected rates increased with the inoculation density increased and the transmission efficiency of WBPH increased with the nymphae instars increased. With an inoculation density of two or three insects per seed- ling, the virus transmission of fourth instar nymphae, or fifth instar nymphae, or macroptery and brachyptery could cause a 100.00 % inci- dence of rice. Different rice growthstages affected the virus transmission efficiency of WBPH. The infected rates of rice from one leaf stage to 30 d seedlings were 100.00 % , and the infected rates of 40 d seedlings ,50 d seedlings ,60 d seedlings and 70 d seedlings were 91.30 % ,4.17 %, 0.00 % and 0.00 % respectively. With the feeding time or the inoculation time increased, the rice infected rates continued to increase. When the viral feeding time was 60.18 h or the viral transmission time was 26.34 h, the rice infected rate of was 100 %. In evaluation of rice resistance to SRBSDD, the viral acquisition period should not be less than 60. 18 hours, and the seedlings were twenty to twenty-five days old, the inoculation density should be two viral nymphaes （fourth or fifth instars） or aduhs per seedling. The viral transmission time should not be less than 26.34 hours. It was suggested that the resistance of the existing WBPH resistance rice varieties （materials） to SRBSDD should be evaluated to explore virus-resistance materials, and provide resistant materials for SRBSDD-resistance rice breeders.