南方水稻黑条矮缩病毒介体昆虫白背飞虱的传毒特性

白背飞虱Sogatella furcifera(Horváth)为传播南方水稻黑条矮缩病病毒(SRBSDV)的媒介昆虫,阐明其传毒特性将有助于了解南方水稻黑条矮缩病的发生流行规律和建立相应的防治方法。本研究通过RT-PCR技术测定了白背飞虱的传毒参数。结果表明,白背飞虱初孵若虫、3龄若虫、5龄若虫、长翅型成虫和短翅型成虫的最短获毒时间分别是11、6、3、2和2min,最长获毒时间分别是19、12、9、8和8min。在26℃时,SRBSDV在不同虫态(初孵若虫、3龄若虫、5龄若虫、长翅型成虫和短翅型成虫)的白背飞虱体内的循回期分别是7～11、5～8、3～7、4～8和3～6d。5龄若虫、长翅型和短翅型成虫在三叶一心稻苗的最短接毒时间为4、5和6min,最长接毒时间为8、10和11min;它们在分蘖初期稻苗上的最短接毒时间分别是5、7和7min,最长接毒时间分别是10、12和12min。白背飞虱获毒后可终身传毒,但不能经白背飞虱卵传毒,单虫最多传毒株数为87株,平均传毒48.3±0.8株。可见,该虫具有较强的获毒能力和传毒能力,秧苗易感染SRBSDV。因此,在防治上应尽量清除田间SRBSDV毒源植物,减少白背飞虱获毒的机会,在秧田期和移栽初期应重点防治飞虱。

Transmission characteristics of Sogatella furcifera:A vector of the Southern rice black-streaked dwarf virus

Sogatella furcifera（Horváth） is an important vector of the Southern rice black-streaked dwarf virus（SRBSDV）.Establishing the transmission characteristics of this species is therefore important to determining the periodicity of this disease and developing effective control methods for it.The presence or absence of SRBSDV in different life-stages of S.furcifera was determined using RT-PCR.The results show that the viral acquisition periods of first instar nymphae,third instar nymphae,fifth instar nymphae,macropters and brachypters were 11-19 min,6-12 min,3-9 min,2-8min and 2-8 min,respectively.At 26℃,the circulative period of SRBSDV in the body of these different life-stages was 7-11 d,5-8 d,3-7 d,4-8 d and 3-6 d,respectively.The shortest periods required for the transmission of the virus to rice seedlings at the three-leaf stage by each of these developmental stages were 4 min,5 min and 6 min,respectively,whereas the longest were 8 min,10 min,and 11 min,respectively.The shortest period required for infection of rice seedlings at the early tillering stage by fifth instar nymphae and macropter and brachypter stages were 5 min,7 min and 7 min,respectively,whereas the longest were 10 min,12 min and 12 min,respectively.Once infected with the virus,individual S.furcifera can remain infectious for life.However,the virus is not passed on to the egg stage.The maximum number of rice plants infected with SRBSDV by a single S.furcifera was 87 and the average was 48.3±0.8.The results indicate that S.furcifera has a strong capacity for both the acquisition and transmission of SRBSDV,and that rice seedlings are highly susceptible to SRBSDV.The prevention and control of SRBSDV requires both effective control of S.furcifera in rice seedling beds and the weeding out of infected rice plants.