Cucumber green mottle mosaic virus in agroecosystems of Ukraine

Abstract

Cucumber green mottle mosaic virus (CGMMV) is a widespread pathogen capable of infecting plants cultivated in both greenhouse and openfield conditions with equal efficiency. The host range of CGMMV is restricted to cucurbit plants whereas induced crop losses may reach 25–50 %. Despite the wide array of available antiviral techniques, CGMMV could not be completely removed from the seed/planting material. In Ukraine, Cucumber green mottle mosaic virus occurs almost exclusively on greenhouse cucumbers. However, data from other countries suggest wide spread of CGMMV on watermelons, melons, cucumbers and squashes grown in both greenhouse and open-field conditions. In this view and taking into account high pathogenicity of CGMMV, we aimed at studying spread of Cucumber green mottle mosaic virus in Ukraine on cucurbit plants in the open-field conditions. Methods: enzyme-linked immunosorbent assay, electron microscopy, statistical methods. Results : Spread of Cucumber green mottle mosaic virus (CGMMV) on cucurbit vegetable crops grown in open-field conditions was analyzed in Ukraine. It was shown that CGMMV is an extremely rare pathogen in open-field conditions in our country. Duringthelast 8 years we have confirmed only several cases of CGMMV infection on cucumbers, squash, pumpkin and melon in Kyiv and Poltava regions. Additionally, half of these cases were mixed infection of 2–3 viruses. From 250 collected samples, CGMMV was detected in 5 plants totaling to only 2,4 %. Importantly, monoinfection of CGMMV was shown exclusively on cucumbers and watermelons, whereas melons and squashes were mixed infected. Melons were typically infected with CGMMV and Watermelon mosaic virus 2 (WMV 2) or with WMV 2 and Zucchini yellow mosaic virus (ZYMV). Squash plants were infected with CGMMV and Cucumber mosaic virus (CMV).Consequently, we have checked commercially available seeds of cucumber, squash, zucchini, melon and watermelon from different producers in Ukraine for virus contamination and have confirmed the occurrence of CGMMV in some seed batches. Conclusions: Long-term observations in Ukraine showed that Cucumber green mottle mosaic virus infected mostly cucumbers cultivated in greenhouses and was only rarely found in cucurbits grown in open-field conditions. Screening of commercially available seed material indicated that 16 % of it was contaminated with CGMMV. Basing on available data, it is presumed that virus-contaminated seed material may pose a major threat of CGMMV occurrence and spread on cucurbits cultivated in open-field conditions.