Characterisation of a variant of zucchini yellow fleck virus (ZYFV), a potyvirus causing a wilt disease of melons in Israel*

A flexuous filamentous virus 750 nm in length was isolated from field-grown melons (Cucumis melo L.) and squirting cucumber (Ecballium elaterium L.). Infection of melon seedlings of most commercial varieties resulted in a lethal wilting, but late infections gave dieback. The virus infected systemically all economically important cucurbit crops. Its coat protein consists of a single polypeptide, 34 500 D in size, encapsidating a single stranded RNA genome of 10.1 kb. Antiserum against the Italian zucchini yellow fleck virus (ZYFV) reacted specifically with the Israeli isolate in both ISEM and Western blot. The virus was aphid transmissible in a non-persistent manner. Based on host range, host reaction and serological data, it is suggested that the virus described is an Israeli variant of ZYFV.