烟粉虱对甘薯种薯带毒率及病毒病发生的影响

Impact of whitefly(Bemisia tabaci)on viruliferous rate of sweet potato storage root and viral disease occurrence

病毒病是影响甘薯产量和品质的重要限制因素。甘薯褪绿矮化病毒(sweet potato chlorotic stunt virus,SPCSV)和甘薯羽状斑驳病毒(sweet potato feathery mottle virus,SPFMV)是危害我国甘薯的主要病毒。甘薯种薯感染SPCSV是甘薯苗期病毒病严重发生的关键因素。本研究分析了甘薯田烟粉虱发生量和带毒率对种薯带毒率及病毒病发生的影响,建立了甘薯种薯感染病毒风险和苗期病毒病发生风险的早期预警方法。结果表明,甘薯田烟粉虱发生量和SPCSV带毒率与种薯SPCSV带毒率密切相关,在田间烟粉虱发生量和带毒率较高的情况下,即使种植不含任何病毒的脱毒试管苗,也会引起较高的种薯带毒率,但不会引起甘薯地上部植株的严重显症。甘薯种薯SPCSV带毒率以及SPCSV和SPFMV复合带毒率与苗期病毒病显症率呈极显著正相关关系,可以利用种薯带毒率预测甘薯苗期病毒病显症率。

Virus disease is a main constraint that influences sweet potato yield and quality.The most important viruses for sweet potato are the sweet potato chlorotic stunt virus(SPCSV)of the genus Crinivirus and sweet potato feathery mottle virus(SPFMV)of the genus Potyvirus.SPCSV-infected sweet potato storage roots incline to develop severe viral disease at the seedling stage.However,the effect of whitefly(Bemisia tabaci)in sweet potato fields on the proportion of SPCSV-viruliferous storage roots and viral disease occurrence remains largely unknown.Here,we report that the amount of whitefly and the rate of SPCSV-viruliferous whiteflies in sweet po-tato fields were closely related to the viruliferous rate of storage roots.When there was a high number of virulif-erous whiteflies in sweet potato fields,a high rate of viruliferous storage roots were triggered,even though virus-free sweet potato cuttings that would not induce severe symptoms in above ground plants had been planted.The SPCSV infection rate and double infection of storage roots with SPCSV and SPFMV presented significant posi-tive correlations with the virus-like symptom rate in sprouts generated from the storage roots.The symptom rate in sprouts can be predicted by the viruliferous rate of storage roots.