During field surveys conducted from July to October 2018–2020 in the eastern part of Georgia (Caucasus region), 145 out of 8000 (1.8%) and 147 out of 6600 (2.2%) grapevine plants, respectively, from ...mother stock/collection fields and commercial vineyards, were found exhibiting typical or suspicious grapevine yellows (GY) symptoms. Most of the symptomatic grapevine plants of Georgian cultivars showed mild symptoms with no berry alterations. Leaf samples from symptomatic plants were analyzed by serological (DAS- -ELISA) and molecular (two previously published protocols of TaqMan triplex real-time PCR, here named Set I and Set II) tools for detecting GY-associated phytoplasmas. The presence of GY phytoplasmas was not detected in any examined grapevines by a serological method. GY phytoplasmas were identified in 22.41% and 6.9% symptomatic plants from mother stock and collection vineyards and in 48.3 and 19.0% symptomatic plants from commercial vineyards by Set I and Set II PCRs, respectively. As expected from previous studies reporting the wide presence of bois noir (BN) in Georgian vineyards, ‘Candidatus Phytoplasma solani’(CaPsol) was detected in most phytoplasma-infected plants (47.6%), with the highest infection rate in Chardonnay. Phytoplasmas belonging to taxonomic group 16SrV were detected in 45.6% of the phytoplasma-infected grapevines. To the best of our knowledge, this is the first report of 16SrV phytoplasmas in Georgia and in the Caucasus region. Further molecular typing of 16SrV phytoplasma strains is necessary to determine if such strains are associated with flavescence dorée (FD). The knowledge of typical GY symptoms and the utilization of accurate diagnostic tools are crucial for preventing pathogen spread and producing healthy planting material. Based on the results obtained in this study, the presence of BN and 16SrV phytoplasmas should be monitored in the next years using triplex real-time PCR.
Potato is an essential food staple and a critical crop for rural livelihoods in the Republic of Georgia, where many phytosanitary risks threaten production.
The objectives of this study were, first, ...to characterize the current seed and ware potato transaction network, value chain, varietal adoption, and phytosanitary risks for Georgia. Second, we modeled scenarios for the spread of an emerging pathogen, Synchytrium endobioticum, in Georgia as part of a geographic risk assessment analysis. Third, we coupled risk estimated in our simulation experiments with risk of reintroduction or invasion of pathogens via international trade or habitat connectivity. We found that a majority of seed potato is obtained from local sources in Georgia, and is of unknown phytosanitary quality.
An expert elicitation workshop was held to characterize the potato value chain as well as potato production more generally in the Republic of Georgia. To characterize future risk of pathogen spread through Georgia we leveraged epidemic network analysis, an analysis of potato cropland connectivity, and an evaluation of international potato trade in a multi-step risk assessment.
Five varieties, including the variety Jelly, made up 65% of planted area throughout the country. Several pathogens and pests were listed as contributing to annual yield loss with S. endobioticum, causing potato wart, identified as the greatest emerging risk to the country. Through simulation analyses of potential spread scenarios within country, we identified municipalities in Adjara and Samtskhe-Javakheti to be at particularly high risk for introduction of potato wart and we recommend enhanced surveillance in these regions. Our analysis of cropland connectivity revealed that the region where Georgia, Azerbaijan, and Armenia meet are at a high risk for local spread of seedborne pathogens such as S. endobioticum. We propose these locations as targets for enhanced surveillance and mitigation strategies.
We introduce these methods as a general framework for the rapid assessment of phytosanitary risks of regional seed systems, especially where information available to guide interventions is scarce.
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•The potato seed system in Georgia was characterized via expert elicitation•We integrated risk based on trade and cropland connectivity•Several regions were identified as targets for pathogen surveillance•Potato wart has a risk of spread in regions identified in epidemic network analysis•Recommendations were made for a national integrated seed health strategy
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