棚栽嫁接西瓜黄瓜绿斑驳花叶病毒病发病动态及其田间扩展研究初报

Outbreak Dynamics and Field-extension of Cucumber Green Mottle Mosaic Virus in Grafted Watermelon Cultured in Greenhouse

为明确棚栽嫁接西瓜黄瓜绿斑驳花叶病毒病发生规律,对该病害的发病、蔓延和影响因素进行研究。毛竹搭建塑料大棚,无毒土壤上常规或低密度移栽健康嫁接西瓜苗,移栽后6、30天剪除部分瓜苗顶叶或倒2叶约半片后,将伤口浸渍在毒源中进行接种诱发,常规密度移栽苗自然生长,低密度移栽苗经整枝始终保持单株独立;健康植株用毒源污染剪刀、手指后整枝或毒源与健康藤蔓摩擦诱发。调查病田病株自然扩展以及拔除清除病健株后直播种子和套种瓜苗的控病效果。目测法定期调查显症病株,酶联免疫双抗体夹心检测法确定病株。接种后植株染病率高。低密度移栽苗:移栽后6天接种的瓜苗24天显症、34天突增、85天高峰,分别比移栽后30天接种的植株长4、4和30天;未接种的也在移栽后70天显症、95天高峰。常规密度移栽苗接种株也有类似趋势。显症病株率和带毒株率与日平均温度关系密切。病株中不同藤蔓上的叶片和相同藤蔓内的叶片既表现显症,也有隐症,甚至终生带毒隐症。病健藤蔓摩擦病株率100.0%,而染毒手指、剪刀整枝病株率则为91.7%和83.3%。病田内病情自然扩展先相邻连续,后点片;病田拔除清除病健株后,直播瓜苗和套种嫁接苗带毒株率分别为82.4%和77.0%,控病效果17.6%和23.0%。棚栽嫁接西瓜苗(植株)从感染黄瓜绿斑驳花叶病毒病到表现症状需要20天左右的潜伏期,继之产生显症病株突增和高峰,温度高,潜伏期短、进入突增和高峰快;隐症病株表现在株间、不同分枝藤蔓叶片间和相同藤蔓不同叶片间;移栽密度对发病无明显影响。田间扩展再侵染先相邻后点片,除了其他途径外,病健藤蔓接触摩擦传病作用大;病地当年连作重发的机率高。

To clarify the rule of cucumber green mottle mosaic virus disease in greenhouse grafted watermelon,the causes,spread and effect factors of the disease were studied.In greenhouse built by bamboos,healthygrafted watermelon plants were transplanted in virus-free soil conventionally or in low-density form.Topleaves of the plants were cut or leaves were cut by half after 6 days and 30 days.Then the wounds were dippedin virus to induce inoculation.Conventional transplanted plants grew naturally,while those in low-density formmaintained after pruning.Healthy plants were induced by pruning with virus-contaminated scissors or fingers,and friction between virus and healthy vines as well.Then,natural spread of sick field and sick plants wasinvestigated.After removing healthy and sick plants,disease control effects of direct seeds and interplantingmelon plants were investigated too.Sick plants with symptoms were researched by visual method regularly,andconfirmed by Double Antibody Sandwich Enzyme-linked immunosorbant assay（DAS-ELISA） method.Plants＇ infection rate was high after inoculation.For transplanted plants in low-density form,inoculated plants whichwere transplanted after 6 days showed symptoms in 24 days,increased rapidly in 34 days and reached peak in85 days,which were 4 days,4 days and 30 days longer than those of plants inoculated 30 days aftertransplanting.Plants without inoculation showed symptoms in 70 days and reached peak in 95 days aftertransplanting.Conventional transplanted plants with inoculation shared a similar trend.Rates of sick plantswith symptoms and plants with virus were closely related to the daily average temperature.In sick plants,leavesbetween different vines and those on the same vines displayed both obvious symptoms and hidden symptoms,and even lifetime hidden symptoms with virus.Sick rate of plants caused by friction between healthy and sickvines reached 100%,while methods of pruning with virus-contaminated fingers and scissors led to the rate of91.7% and 83.3%.In sick field,virus spread adjacently,and then substantially.After getting rid of sick plantsin the field,sick rates of direct seeding melon plants and interplanting grafted plants were 82.4% and 77.0%,while the rates of disease control effect were 17.6% and 23.0% respectively.In conclusion,it takes 20 days＇ incubation for greenhouse grafted watermelon（plants） to display sick symptoms from infecting cucumber greenmottle mosaic virus.Afterwards,the amount of sick plants increases rapidly and reaches the peak.It hasfeatures of high temperature,short incubation,sudden increase and reaching the peak rapidly.The symptoms ofhidden sick plants show in leaves between plants and vines,and also different leaves on the same vines.Theinfluence of density of transplanting on the disease is not obvious.The disease spreads in the field adjacentlyfirst,and then substantially.The effect of friction between healthy and sick vines on virus transmission is greatbesides other methods.Succession cropping in sick field of the year has high probability of recurrence.