番茄褪绿病毒病在山东设施西葫芦上的发生及潜在危害

番茄褪绿病毒tomato chlorosis virus (ToCV)是我国蔬菜生产的重要新发病毒，其寄主范围逐年扩大。2019年10月项目组在山东寿光西葫芦温室调查时发现部分叶片呈现黄化、脉间褪绿，类似于ToCV侵染症状，并伴有烟粉虱发生。利用特异性引物检测发现，扩增的目的片段与GenBank中登录的侵染番茄的ToCV基因序列(登录号：KC887998.1)同源性高达99.58%,充分说明西葫芦植株已被ToCV侵染。通过对病毒病发生规律和烟粉虱虫口数量调查发现，西葫芦定植后1个月表现侵染症状的植株为2.0%,定植后2个月达到4.2%,定植后4个月后高达68.2%,病毒发生呈指数增长，而烟粉虱虫口数量却维持较低密度。从济南和德州采集的西葫芦疑似病叶和烟粉虱中也检出ToCV病毒，说明该病毒可能已经在山东省设施西葫芦主要种植区普遍发生，并经烟粉虱广泛传播，需引起高度重视。

Occurrence of tomato chlorosis virus and its potential threat to greenhouse zucchinis in Shandong province

Tomato chlorosis virus (ToCV) has become a new important virus in vegetable industry in China and its host range keeps expanding. In October, 2019, yellow leaves and chlorosis between veins similar to the symptoms of tomato caused by ToCV infections were noticed on zucchini plants in a greenhouse located in Shouguang county. The gene fragment amplified using a pair of specific primers was cloned, sequenced and BLAST in GenBank. The results showed that its sequence shared a high similarity (99.58%) with that of ToCV registered in GenBank (Acc. no. KC887998.1), indicating that zucchini plants were commonly infected by ToCV. A preliminary investigation in the greenhouse in Shouguang indicated that the percentage of symptomatic zucchinis was 2.0% in a month, 4.2% in two months, and 68.2% in four months, respectively, after planting, and an exponential development of ToCV was observed, while the number of Bemisia tabaci remained at a low level. ToCV was also detected in the suspected leaves of zucchini and B.tabaci collected from Jinan and Dezhou cities. The results suggested that ToCV had already spread widely in the areas where zucchinis were cultivated in greenhouse in Shandong province, which should to be taken seriously.