Brief Summary of Minutes of Annual Meeting

The annual meeting of the multistate project WERA-20, “Management of Diseases Caused by Systemic Pathogens in Temperate and Sub-Tropical Fruit Crops and Woody Ornamentals,” was held May 6–8, 2026, at the University of Hawaiʻi Maui College, Maui, Hawaiʻi. The meeting was hosted by Drs. Jing Zhou and Michael Melzer, Department of Plant and Environmental Protection Sciences, College of Tropical Agriculture and Human Resilience (CTAHR), University of Hawai'i at Manoa.

 Dr. Jing Zhou, Chair of the 2026 WERA-20 Annual Meeting, welcomed participants on behalf of the University of Hawaiʻi and the local agricultural community. Dr. Kevin Olival, Associate Dean and Associate Director of Research, CTAHR, University of Hawaiʻi at Mānoa, welcomed participants to Maui and expressed his best wishes for a productive meeting. Dr. Olival provided an overview of CTAHR and highlighted the importance of WERA-20 as a national network for protecting specialty-crop health through innovative diagnostic approaches, collaborative national clean plant networks, cross-institutional and transdisciplinary research, and Extension activities that benefit specialty-crop industries and strengthen their global competitiveness.

 Ms. Rogerene “Kali” Arce, Director of the Maui County Department of Agriculture, provided an overview of the department’s programs and initiatives aimed at promoting a resilient and diversified local economy, strengthening food security by helping farmers and ranchers succeed, and improving community health through greater access to locally grown foods.

 Dr. Naidu Rayapati, Administrative Advisor for WERA-20, Washington State University, welcomed the participants and provided an overview of the WERA--20 business meeting and addressed organizational matters. Dr. Robert Alvarez-Quinto, Department of Plant Pathology, College of Food, Agricultural and Natural Resource Sciences, University of Minnesota, was elected Secretary for the 2026–2027 term and is expected to serve as Chair for the 2027 annual meeting. Based on the group’s suggestion, the 2027 meeting is tentatively planned for Minneapolis, Minnesota, in July/August 2027, subject to approval by the Western Association of Agricultural Experiment Station Directors. Since the current 5-year project is set to terminate on 09/30/2027, the group discussed working on a new project proposal for review by the Multi-State Review Committee.

 Dr. Amer Fayad, National Program Leader, Division of Plant Systems Protection, Institute of Food Production and Sustainability, USDA National Institute of Food and Agriculture (NIFA), provided updates on NIFA programs and funding opportunities. He encouraged WERA-20 participants to consider opportunities across NIFA programs to support collaborative research, Extension, and innovation addressing emerging challenges in specialty-crop health and advancing U.S. agriculture and its global competitiveness.

 The main program included research and program updates from WERA-20 participants attending both in person and virtually, followed by a special session entitled “Application of NCPN Principles to Manage Tropical and Sub-Tropical Plant Diseases in Hawaiʻi.” The special session provided an opportunity to discuss the applicability of National Clean Plant Network (NCPN) principles and approaches to the management of systemic pathogens in tropical and subtropical cropping systems. Presentations were followed by group discussions focused on opportunities for collaboration, knowledge exchange, diagnostics, clean plant programs, and disease-management strategies.

 The meeting concluded with a field trip highlighting agricultural production systems and cropping practices in Maui County. The field visit provided participants with an opportunity to observe local production systems, discuss challenges associated with managing plant diseases in tropical and subtropical environments, and identify potential areas for future research and collaborative activities.

 Overall, the 2026 WERA-20 Annual Meeting strengthened communication and collaboration among participating land-grant universities, USDA agencies, clean plant programs, regulatory organizations, and other stakeholders. The meeting reinforced the value of WERA-20 as a national forum for coordinating research, diagnostics, clean plant initiatives, and Extension activities addressing systemic pathogen diseases in specialty crops and woody ornamentals.

Naidu Rayapati, Washington State University

Grapevine leafroll disease (GLD) remains a significant threat to the sustainability and profitability of Washington’s grape and wine industry, which has an estimated economic impact of $10.56 billion. Although current management strategies provide encouraging results, continued disease occurrence and the complexity of virus epidemics require improved understanding of the factors driving GLD spread and better tools to reduce economic losses. This research focused primarily on Grapevine leafroll-associated virus 3 (GLRaV-3), the principal virus associated with GLD in Washington vineyards. Research demonstrated extensive genetic diversity of GLRaV-3 in Washington compared with diversity reported from other grape-growing regions. Understanding this diversity is important because genetically distinct virus variants may differ in their epidemiology, transmission, interactions with grapevines, and responses to management practices. 

Studies were conducted to determine how grape mealybugs (Pseudococcus maritimus) contribute to the spread of genetically diverse GLRaV-3 populations. First- and second-instar mealybug nymphs were collected from infected Malbec grapevines carrying distinct GLRaV-3 variants and evaluated for their ability to transmit the virus to Chardonnay seedlings under greenhouse conditions. Results demonstrated that individual mealybugs can acquire and transmit a single GLRaV-3 variant or multiple distinct variants simultaneously. This finding provides important evidence that insect vectors can contribute to the movement and maintenance of viral genetic diversity within vineyards.

Additional experiments examined transmission of GLRaV-3 together with Grapevine virus E (GVE), an unrelated virus frequently detected in vines exhibiting severe GLD symptoms. Greenhouse experiments demonstrated that individual grape mealybug nymphs feeding on vines co-infected with GLRaV-3 and GVE can acquire and simultaneously transmit both viruses. Vineyard surveys also demonstrated frequent co-occurrence of GVE and GLRaV-3 in symptomatic vines. These findings identify vector-mediated co-transmission as a potential mechanism contributing to complex viral infections in vineyards. They also suggest that management practices targeting GLRaV-3 and its mealybug vector could reduce opportunities for GVE dissemination, although the importance of this “hitchhiking” mechanism under field conditions requires further investigation. 

The project also supported Washington’s grapevine certification program. Testing of 36,205 G2/G3 vines from 104 wine grape cultivars and 10 rootstocks detected GLRaV-3 in 256 individual vines, representing an overall incidence of 0.71%. Grapevine red blotch virus and other pathogens included in the testing program were not detected. Positive vines were identified for removal, helping maintain the integrity of certified mother blocks and supporting the continued availability of clean, certified grapevine planting material.

Segun Akinbade, Washington State Department of Agriculture

Little Cherry Disease (LCD) is one of the major diseases of sweet cherry (Prunus avium) and sour cherry (P. cerasus) in Washington State. Although this disease is not new in the state, its recent resurgence has raised concern among cherry growers and nurseries across the state and elsewhere where cherry trees are grown. The disease reduces cherry fruit size and sugar content. There is no known cure for the disease once a tree is infected. Growers are left only with the option to remove infected trees, resulting in huge losses to cherry growers.

 The Fruit Tree Certification Program of the Washington State Department of Agriculture has been at the forefront of efforts to mitigate the spread of this disease in the program's nurseries. For three consecutive years, the Certification Program has obtained a grant through the United States Department of Agriculture (USDA) Animal and Plant Health Inspection Service (APHIS) Protection Act Section 7721 (PPA 7721) to survey nurseries producing certified cherries across the state. For the survey, around 500 to 700 mother trees were sampled each week during May and June and transported to the certification lab in Prosser. The total number of samples collected annually was approximately 3,000.  Samples were tested using Real-Time Polymerase chain reaction (qPCR) for the presence of Little cherry virus 1 (LChV1), Little cherry virus 2 (LChV2), and Western x Phytoplasma. Extracts from the samples were also tested for Prune dwarf virus (PDV), Prunus necrotic ringspot virus (PNRSV), and Cherry leaf roll virus (CLRV).

The certification program collaborated with Washington State University (WSU) Extension, Yakima, WA, and Ruff Country K9 LLC, Buhl, ID, to use trained canines to detect LCD pathogens in three of the four nurseries the program surveyed in 2025. The dogs were run along trees that were either negative or positive for LCD pathogens in the lab. The dogs confirmed 32 of 34 positive mother trees they sniffed. One of the trees that the two dogs didn’t confirm might have been a result of sample error, while the second tree, in which LChV1 was detected in the lab, was a challenge for both dogs because they were not trained in LChV1 detection. The two dogs detected an extra 11 and 10 positive trees, respectively. These extra trees were previously negative by qPCR.

Results from this study were shared with the four nurseries that participated in the survey, and all trees that tested positive for any LCD pathogen were deregistered. A follow-up visit to the nurseries with infected materials was conducted to ensure that the trees were removed from registered blocks.

LCD remains a major threat to cherry growers across Washington State. To ensure the program's nurseries remain a major source of clean cherry planting stock, the program has made it mandatory to test all cherries in the program at least once every 36 months for the presence of LCD pathogens. The program is also looking into investing in the use of canine dogs for the detection of LCD pathogens.

Maher Al Rwahnih, University of California, Davis

FPS clean plant collections continue to grow, and FPS is now offering import and quarantine services for berries in addition to the established grape and fruit tree programs. A micropropagation unit is being added to increase capacity for plant production and better meet industry needs for timely release of plant material. Cryotherapy is being used for virus elimination in fruit trees. FPS’s biggest challenge in the last decade is the infection of the Russell Ranch Vineyard foundation grapevine collection with grapevine red blotch virus. One greenhouse to protect grapevine material indoors was constructed in 2024; phase 2 of this effort is a screenhouse that is expected to be completed in summer 2026. These are great accomplishments towards protecting the invaluable grapevine collection.

Rose imports were briefly delayed this winter while FPS updated SOPs to comply with USDA-APHIS’s increased import regulations due to detection of Ralstonia solanacearum race 3, biovar 2 in roses in the Netherlands. This bacterium is a significant threat to potatoes and would be catastrophic if introduced to the US. Any rose material imported to FPS under controlled import permit will be screened Ralstonia before propagation.

Grapevine red blotch virus has been a major challenge for the foundation grapevine program. We recently completed a research project to evaluate spring qPCR for detection of GRBV. For the study, virus-free sentinel vines were planted at the Russell Ranch Vineyard, known to have GRBV inoculum and vectors present. We tested each vine spring, summer, and fall to track how quickly a vine gets infected in those conditions, and when we can detect the infection. We found that the majority of GRBV infections identified in a growing season are detected in the spring. Full text of article is available in Klaassen and Al Rwahnih, 2026.

Georgios Vidalakis, University of California, Riverside

In this report period, October 2025 – June 2026, we continued to support the suppression and eradication efforts against Huanglongbing (HLB) in California, where the number of positive trees has reached 10,565 and the HLB quarantine zones are expanding in the coastal and southern regions of the state. The University of California, Riverside, National Clean Plant Network (NCPN) Citrus Center, namely the Citrus Clonal Protection Program (CCPP) collaborated with the California Department of Food and Agriculture's (CDFA) Citrus Nursery Stock Pest Cleanliness Program and distributed 58,738 clean citrus propagation units (buds), tested for HLB as well as virus and viroid diseases, from 411different citrus accessions, to 660 nurseries, producers, scientists, and the public, sourced from 1,227 pathogen-tested citrus budwood trees. The CCPP also tested 56 citrus introductions from 7 countries with 3,153 diagnostic tests intercepting 12 different types of pathogens in 20 introductions (35.7%), including HLB, viruses and viroids and performed pathogen elimination/therapy on 56 citrus accessions with 443 tissue cultures. The CCPP maintained 548 inquiries under quarantine and performed 2,066 laboratory and 6,952 biological pathogen detection tests for HLB, virus and viroid diseases resulting in the release from quarantine of 29 citrus accessions. 

In collaborative efforts with WERA 20 members and experts in the USA and other citrus-producing countries, we reviewed the global status, disease impacts, strain diversity, and management strategies of citrus tristeza virus (CTV), including quarantine, budwood certification, tolerant rootstocks, vector management, and cross-protection; developed and evaluated a rapid, portable, colorimetric RT-LAMP assay for CTV detection using micro-homogenizer-based sample preparation, cellulose paper nucleic-acid capture, optimized primers, DMSO-mediated reduction of false positives, and lyophilized reagents for greenhouse and field-adaptable testing; biologically characterized citrus viroid VII (CVd-VII) by evaluating host range, seed-transmission risk, tissue distribution for diagnostic sampling, and interactions with other citrus viroids; reviewed physiological, environmental, cultural, anatomical, biochemical, molecular, and metabolic factors affecting grafting success, graft compatibility, graft incompatibility, and plant re-establishment; developed and validated a real-time RT-qPCR assay for citrus yellow vein clearing virus (CYVCV) using public and in-house sequence data, MIQE guidelines, DAVN principles, and inter-laboratory validation across NCPN and regulatory laboratories; and optimized selected qPCR and RT-qPCR parameters for improved detection of ‘Candidatus Liberibacter asiaticus’ (CLas), including PCR plate color, pipetting consistency, PCR enhancers, and reverse transcription to improve low-titer detection and reduce technical variability. 

WERA 20 members, presented their work (articles in magazines, presentations, keynote and invited speakers in conferences and extension and outreach events) at the Citrograph magazine, the 2026 Conferences of the Southern African Society for Plant Pathology and the American Phytopathological Society Pacific Division, the 2026 Australian Citrus Congress, as well as the 2026 University of California events of the Fall Citrus meeting and the Citrus day and the National Clean Plant Network Quality Workshop with the participation of hundreds of scientists, regulators and growers from around the world.

Ioannis Tzanetakis, University of Arkansas

During this reporting period, the Arkansas program continued to advance applied plant virology in support of clean plant programs, specialty crop certification, and science-based regulatory decisions. Activities focused on improving diagnostic confidence for difficult-to-detect viruses, developing artificial positive controls, characterizing vector-virus interactions, and strengthening bioinformatic pipelines for virus discovery from high-throughput sequencing data.

• Advanced ViMAPC and qViMAPC diagnostic platforms. The program expanded the use of Virus-Mimicking Artificial Positive Controls (ViMAPCs) for endpoint PCR and SYBR-based qPCR and further developed TaqMan qViMAPCs. These controls are designed to behave more like virus-positive plant samples than simple synthetic controls, while allowing laboratories to distinguish true infection from potential laboratory contamination. More than 30 ViMAPCs have now been developed, and tests were replicated across different laboratories and users. The 2026 work also demonstrated that the TaqMan qViMAPC approach can be adapted by incorporating a spacer and target probe into the forward primer design.
• Strengthened diagnostics for berry certification and clean plant programs. Diagnostic assay development continued for economically important berry viruses, including blueberry scorch virus and blueberry virus S. The work resulted in endpoint and quantitative PCR assays that can detect and discriminate between the two viruses, supporting more reliable testing in certification, quarantine, and clean plant settings.
• Clarified rose rosette emaravirus dynamics in eriophyoid mites. The program developed and applied a direct TaqMan RT-PCR/RT-PCR approach capable of detecting rose rosette emaravirus in individual eriophyoid mites. Using vector and non-vector comparisons the work provided evidence that rose rosette emaravirus undergoes active replication in Phyllocoptes fructiphilus. These data help resolve questions regarding the transmission biology of rose rosette disease and provide a framework for future studies of mite-borne emaraviruses.
• Expanded knowledge of vector transmission in blackberry. Experimental greenhouse studies demonstrated that the grape mealybug, Pseudococcus maritimus, is an efficient vector of blackberry vein banding-associated virus. This finding improves understanding of disease spread in blackberry systems and identifies a vector that should be considered in disease management and certification contexts.
• Improved HTS-based virus discovery and diagnostic interpretation. 0 (beta version) as a comprehensive two-pass detection system for viral and viroid sequences from high-throughput sequencing data. The system uses multiple orthogonal approaches, including host decontamination, multi-tier DIAMOND filtering, VirSorter2 machine-learning classification, RdRP/HMM screening, consensus voting, and interactive HTML reporting. This development is intended to maximize sensitivity and specificity while producing outputs that can be interpreted by diagnostic laboratories. We are aiming to optimize the pipeline by testing already screened material and determine if the new pipeline is at least as good as others that ae already in use.
• Contributed to international taxonomy and virus discovery efforts. The program contributed to the 2025 ratified taxonomy changes from the ICTV Plant Viruses Subcommittee and to a broad international study that expanded understanding of plant rhabdovirus diversity through the discovery of viruses representing 32 putative novel species.

Alexander V. Karasev, University of Idaho

The virome of grapevines grown in the State of Idaho was continued to be characterized in 2023-2025, with the overall goal of developing diagnostic tools for virus and virus-like disorders in wine grapes. More than 380 leaf and petiole samples were collected from symptomatic grapevines in 10 vineyards in Canyon and Nez Perce counties of Idaho and in Malheur County of Oregon and subjected to high-throughput sequencing (HTS) and RT-PCR testing. Two viruses were found in a single vineyard in eastern Oregon, grapevine rupestris vein feathering virus (GRVFV) and grapevine-associated tymo-like virus (GaTLV); these are first reports of GRVFV and GaTLV in Oregon. A new picorna-like virus was identified in grapevines from a 21-year-old ‘Tempanillo’ block in eastern Oregon exhibiting leaf chlorosis and interveinal reddening. This new virus was named grapevine-associated picorna-like virus (GaPLV). GaPLV has a monopartite, positive-sense, single-stranded RNA genome of 9021-nt, with a single open reading frame encoding a polyprotein that encompasses an RNA dependent RNA polymerase (RdRP), a helicase, a chymotrypsin-like protease, and three capsid proteins. The arrangement of these conserved domains in the polyprotein is so far unique among picorna-like viruses, with two structural (capsid) proteins in the N-terminal region, upstream of all other conserved domains, and one structural (capsid) domain close to the C-terminus of the polyprotein, downstream of the RdRP. In phylogenetic analysis, RdRP of GaPLV grouped inside the order Picornavirales, but outside of the known families of picorna-like viruses, at the base of the clade that includes Iflaviridae and Polycipivirdae. The presence of GaPLV in the original ‘Tempranillo’ samples was confirmed by RT-PCR amplifications and Sanger sequencing. Virus surveys conducted in 2023 and 2024 from five commercial vineyards in southwestern Idaho and eastern Oregon revealed GaPLV presence in six wine grape cultivars.

Alejandro Olmedo-Velarde and Adriana Larrea-Sarmiento, Iowa State University

Grapevine virus surveys and characterization in Iowa: During 2025–2026, surveys of cold-hardy grapevine cultivars were conducted across multiple Iowa vineyards to characterize virus populations associated with Midwest grape production systems. A total of 133 samples were collected and subjected to molecular diagnostics included RT-PCR assays targeting economically important grapevine viruses, including grapevine leafroll-associated virus 3 (GLRaV-3), grapevine red blotch virus (GRBV), grapevine fleck virus (GFkV), grapevine rupestris stem pitting-associated virus (GRSPaV), grapevine pinot gris virus (GPGV), tomato ringspot virus (ToRSV), and grapevine vitiviruses. High-throughput sequencing (HTS) and rolling-circle amplification (RCA)-based approaches enabled the recovery and characterization of viral genomes from Iowa grapevine isolates. Phylogenetic analyses were conducted to compare Midwest isolates with previously reported global virus populations. Additionally, HTS analyses identified a putative novel vitivirus associated with cold-hardy grapevine cultivars in Iowa. Ongoing studies are focused on genome validation and biological characterization of this virus. These activities contributed to one of the first broad virome characterization efforts focused on cold-hardy grape production systems in Iowa and the Midwest. 

Characterization of novel viruses associated with red-osier dogwood: A viromics study was conducted on symptomatic red-osier dogwood (Cornus sericea) plants collected in Iowa exhibiting chlorotic and necrotic ringspot symptoms. Ribodepleted total RNA was subjected to high-throughput sequencing followed by de novo assembly, BLAST analyses, phylogenetic reconstruction, and confirmatory RT-PCR assays. Multiple novel viruses were identified and characterized from symptomatic dogwood plants, including viruses associated with the genera Allexivirus, Blunervirus, and Trirhavirus, as well as a highly divergent tombus-like virus. Genome organization and phylogenetic analyses supported classification of several viruses as novel species. Mixed infections involving multiple viruses were detected in individual plants, highlighting the complexity of the dogwood virome and the need for continued studies to evaluate epidemiology, symptom association, and potential transmission pathways in ornamental woody hosts.

Characterization of a novel closterovirus associated with fig mosaic disease: Studies were conducted to characterize viruses associated with fig mosaic disease (FMD) in symptomatic Ficus carica plants collected in Iowa. High-throughput sequencing (HTS), RT-PCR, dsRNA extraction, and RACE approaches identified fig mosaic virus (FMV) and a putative novel closterovirus, tentatively named fig virus C (FiVC). Complete genome characterization showed that FiVC possesses a typical closterovirus genome organization approximately 18.1 kb in length. Phylogenetic analyses supported classification of FiVC as a novel member of the genus Closterovirus. This work expands current knowledge of viruses associated with fig mosaic disease and highlights the importance of continued surveillance of viruses infecting perennial fruit crops in the United States.

Brevipalpus-associated virome research: Activities also focused on publishing prior research on the characterization of viruses associated with Brevipalpus mites, important vectors of several economically significant plant viruses affecting fruit crops and ornamentals worldwide. Virome analyses and molecular characterization efforts expanded knowledge regarding virus diversity associated with Brevipalpus spp. and provided additional genomic resources relevant to understanding vector-associated viral communities and potential plant virus interactions.

Francisco Ochoa Corona and Andres Espindola Camacho, Oklahoma State University

From Dr. Ochoa Corona

Rose rosette virus (RRV), species Emaravirus rosease, is a negative-sense, ss-RNA virus in the genus Emaravirus, family Fimoviridae, and the causal agent of rose rosette disease (RRD). RRV is transmitted by two windborne mite species (Phyllocoptes fructiphilus and P. arcani). RRD devastated rose gardens in the U.S.A. and is reported in Canada and India. RRV has caused severe economic losses to the rose nursery, and landscape industry in the U.S. and threatens other rose industries worldwide. Loop-mediated isothermal amplification (LAMP) for RRV can be implemented in quarantine labs and nurseries. Although symptoms are characteristic, early diagnosis is misleading and may appear like herbicide damage. RRD takes a long incubation time for symptom visualization. The virus tropism migrates the virus to the roots, where it overwinters. Direct virus-adsorption into polypropylene-PCR tubes was developed to capture RRV virions to circumvent kit-based RNA extraction. RT-PCR and numerous primer sets are available. A synthetic artificial positive control (APC), conceived de novo by concatenating sense and anti-sense primers, allowed the development of a plasmid positive control for use with most RRV and eriophyid mite reported primers. Moreover, RRV gene sequences P3 and P4 were analyzed, and two sets of four LAMP primers were designed. RT-LAMP takes 1 hour at 64°C (RRV-P3) and 66.5ºC (RRV-P4) using either a thermocycler or portable dry bath. RPA-exo is also available.   Electronic probes (e-probes) applying the bioinformatic pipeline E-probes Diagnostic Nucleic-acids Analysis integrated with the Microbe Finder platform (EDNA-MiFi®) is being developed for the detection of over 20 rose-infecting viruses in a single sample in High-Throughput Sequencing (HTS) non-assembled data. A large-scale multiple-sequence alignment of all targeted viral pathogens and their close neighbors was performed within this framework using MiProbe^TM. The curation of e-probes eliminated non-specific e-probes, and the theoretical limit of detection of the curated e-probe sets was predicted in silico and tested in vitro. Preliminary and empirical observations indicated RRV is not evenly distributed in the plant during infection. Therefore, a sampling method is needed to support biosecurity surveillance of RRV in non-infected areas and rose breeding. A pilot experiment with rose plants infected with RRV was empirically divided into four segments or quadrants. Symptomatic and asymptomatic leaves and young branches were sampled in each quadrant. RRV was detected in symptomatic and non-symptomatic RRD tissue from Oklahoma. The progress sampling asymptomatic roses for routine surveillance in areas where RRV is not yet reported was discussed. 

From Dr.Espindola Camacho.
HTS pipelines are commonly validated using single-pathogen samples or datasets without fully defined composition. These designs provide limited information about limits of detection, simultaneous pathogen detection, and cross-detection under complex backgrounds. Since Citrus production is threatened by diverse viral, viroid, bacterial, and fungal pathogens, research has been done in cooperation with, Sohrab Bodaghi and Georgios Vidalakis 9Uiversity of California, Riverside using Citrus crop as a model for creating a need for broad yet reliable high-throughput sequencing (HTS) detection. Results using ART v2.5.8, were shown using a standardized artificial benchmark comprising a 31-pathogen high-complexity master mix, a near-neighbor negative mix, and host-only controls. Eleven abundance levels and 20 replicates per level enable reproducible assessment of sensitivity, LoD95, specificity, and taxonomic cross-detection across HTS pipelines. The datasets served as a standardized evaluation framework and were used to compare four commonly used tools: Kraken2, Bowtie2, EDNA, and BLASTn. The results shared demonstrated that artificial master/master-neighbor datasets are a practical, shareable benchmark resource to quantify trade-offs among detection tools and support standardized validation of HTS diagnostics. 

Mary Sutton, University of Georgia

Citrus in an emerging industry for the state of Georgia. One of the goals of the UGA citrus extension program is to increase grower awareness and knowledge of quarantine diseases. Efforts this past year have focused on one-on-one grower interactions to provide hands-on training in identifying symptoms of quarantine diseases, such as Huanglongbing (HLB). In addition. In addition, 5 meetings and trainings were conducted to increase citrus growers, county agent, and homeowner knowledge of quarantine citrus diseases. These meetings focused on disease and vector identification and in differentiating quarantine disease symptoms from other diseases and common physiological issues. In total, these trainings and meetings have reached over 150 people in the southeast region.

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8. Ouro-Djobo, A., Obasa, K., Oladokun, J. O., Sétamou, M., Al Rwahnih, M., and Alabi, O. J. 2026. Relative occurrence and seasonal variations of wheat-infecting viruses in Texas. Plant Dis. https://doi.org/10.1094/PDIS-06-25-1277-RE.
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11. Liu, C.-W., Bodaghi, S., Keremane, M. L., Kalish, B., Vidalakis, G., & Tsutsui, H. (2026). Rapid colorimetric detection of Citrus tristeza virus combining portable sample preparation and reverse transcription-loop mediated isothermal amplification. SLAS Technology, 37:100398. https://doi.org/10.1016/j.slast.2026.100398
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16. Georgios Vidalakis. 2026. The Citrus Clonal Protection Program: Clean budwood facts and misconceptions. Citrograph. Vol. 17:2, Spring 2026 p.42-46. https://citrusresearch.org/citrograph/archive
17. Danelle K. Seymour, Philippe Rolshausen, M. Imran Hamid, Paulina Quijia-Lamina, German Villalba-Salazar, Emmanuel Avila de Dios, Christopher Wallis, Georgios Vidalakis and Kim D. Bowman. 2026. Evaluating the Potential of New Huanglongbing-tolerant Rootstocks for Use in California. Citrograph. Vol. 17:3, Summer 2026 p.46-48. https://citrusresearch.org/citrograph/archive
18. Toni Siebert Wooldridge, Karene Trunnelle, Robert Krueger, Brittany Moreland, Paulina Quijia-Lamina, German Villalba-Salazar, Georgios Vidalakis and Tracy Kahn. 2026. Recently Released Cultivars Enhances California Citrus Diversity. Citrograph. Vol. 17:3, Summer 2026 p.56-59. https://citrusresearch.org/citrograph/archive
19. Rubino, L., Abrahamian, P., An, W., ... Tzanetakis, I.E. et al. 2025. Summary of taxonomy changes ratified by the International Committee on Taxonomy of Viruses from the Plant Viruses Subcommittee, 2025. Journal of General Virology 106:0.002114. https://doi.org/10.1099/jgv.0.002114
20. Aboughanem-Sabanadzovic, N., Tzanetakis, I.E., Thekke-Veetil, T. and Sabanadzovic, S. 2026. Pseudococcus maritimus Ehrhorn (Hemiptera: Pseudococcidae) is an efficient vector of blackberry vein banding-associated virus (BVBaV) under experimental greenhouse conditions. Journal of Applied Entomology 1-4. https://doi.org/10.1111/jen.70114
21. Botermans, M., de Koning, P.P.M., Westenberg, M., Adams, I.P., ... Tzanetakis, I.E. et al. 2026. Expanding insights into plant rhabdovirus diversity through the discovery of viruses representing 32 putative novel species. Archives of Virology 171:156. https://doi.org/10.1007/s00705-026-06609-1
22. Sierra-Mejia, A., Adams, R. and Tzanetakis, I.E. 2026. Host-dependent virus accumulation dynamics of blackberry chlorotic ringspot virus in two Rubus species. Virology Journal 23:71. https://doi.org/10.1186/s12985-026-03092-7
23. Druciarek, T.Z., Rojas, A.J. and Tzanetakis, I.E. 2026. Rose rosette emaravirus dynamics in eriophyoid mites: implications for virus transmission. Experimental and Applied Acarology 96:45. https://doi.org/10.1007/s10493-026-01135-w
24. Villamor, D.V.V., Stainton, D. and Tzanetakis, I.E. 2026. Development of end-point and quantitative polymerase chain reaction assays to detect and discriminate between blueberry scorch virus and blueberry virus S. Journal of Virological Methods 341:115324. https://doi.org/10.1016/j.jviromet.2025.115324
25. *Reyes-Proano, E., Orellana, G.E., Lee, J., and Karasev, A.V. 2026. First report of grapevine rupestris vein feathering virus and grapevine tymo-like virus in Oregon wine grapes. Plant Disease 110: published on-line March 5, 2026 (https://doi.org/10.1094/PDIS-02-26-0293-PDN).
26. *Reyes-Proano, E., Gulyaeva, A.A., Orellana, G.E., Lee, J., Koonin, E.V., and Karasev, A.V. 2026. Grapevine-associated picorna-like virus, an unusual virus identified in wine grapes (Vitis vinifera L.). Virology 620 (7): 110918 (https://doi.org/10.1016/j.virol.2026.110918).
27. Ault, N., Jarugula, S., Mitra, A., Foster, Z., Grunwald, N. and Naidu, R.A. 2025. A genomics-based, real-time tracking and surveillance system to manage grapevine leafroll disease in Pacific Northwest vineyards. Northwest Center for Small Fruits Research Conference, November 18-19, 2025. The Dalles, OR (Poster presentation)
28. Jarugula, S., Mitra, A., Thammina, C., Chaudhary, P., Ault, A., Grunwald, N. and Naidu, R.A. 2025. Tracking genetic variants of Grapevine leafroll-associated virus 3 for disease prevention and control in Pacific Northwest vineyards. Northwest Center for Small Fruits Research Conference, November 18-19, 2025. The Dalles, OR (Oral Presentation).
29. Chaudhary, P., Jarugula, S., Movva, A. and Naidu, R.A. 2026. Testing grapevines in registered mother blocks for harmful viruses to strengthen clean planting material supply chain. WineVit-2026, Kennewick, WA. February 10-11, 2026 (Poster Presentation).
30. Jarugula, , Mitra, A., Thammina, C., Chaudhary, P., Ault, N., Grunwald, N. and Naidu, R.A. 2026. Co-transmission of grapevine-infecting viruses by grape mealybugs. WineVit-2026, Kennewick, WA. February 10-11, 2026 (Poster Presentation).
31. Jarugula, S., Mitra, A., Thammina, C., Chaudhary, P., Ault, N., Grunwald, N. and Naidu, R.A. 2026. Co-infection of distinct viruses in grapevines highlights the importance of vector-driven epidemiology in grapevine leafroll disease. Phytopathology 116:6S, S2.30 (Oral Presentation).
32. Chaudhary, P., Jarugula, S., Movva, A. and Naidu, R.A. 2026. Virus testing of registered grapevine mother blocks to support a clean planting material supply chain. Phytopathology 116:6S, S2.31 (Poster Presentation).
33. Dahan, J., Orellana, G.E., *Reyes-Proano, E., Lee, J., and Karasev, A.V. 2025. New virus found in wine grapes. Idaho Association of Plant Protection, Annual Meeting, November 6, 2025. Twin Falls, ID (oral presentation).
34. Karasev, A.V. and Lee, J. 2025. Impact of grapevine leafroll-associated virus 3 genetic variants and emerging viruses on wine grape quality in the Pacific Northwest. Northwest Center for Small Fruit Research, Annual Meeting, November 18, 2025. The Dalles, OR (poster presentation).
35. Dahan, J., Orellana, G.E., *Reyes-Proano, E., Lee, J., and Karasev, A.V. 2026. Grapevine-associated cogu-like Idaho virus, a new phenuivirus infecting grapevines in Idaho and Oregon, 2026 American Phytopathological Society Pacific Division Meeting, Pullman, WA, March 25, 2026 (oral presentation).
36. Karasev, A.V. 2026. An unusual picorna-like virus identified in wine grapes. WERA20 Meeting, May 6, 2026. Kahului, HI (oral presentation).

1. *Nakasato, K., *Casey C., Olmedo-Velarde, A., Larrea-Sarmiento, A., and collaborators. 2026. Characterization of novel viruses associated with red-osier dogwood (Cornus sericea) in Iowa. WERA20 Meeting, May 7, 2026 Kahului, HI (Oral Presentation)
2. *Casey, C., Olmedo-Velarde, A., Larrea-Sarmiento, A., and collaborators. 2026. Characterization of virus populations in cold-hardy grapevine in Iowa. WERA20 Meeting, May 7, 2026 Kahului, HI (Oral Presentation)
3. *Casey, C., Olmedo-Velarde, A., Larrea-Sarmiento, A., and collaborators. 2026. Characterization of virus populations in cold-hardy grapevine in Iowa. Presented at the Biennial All Iowa Virology Symposium, Ames, Iowa. March 6, 2026.
4. **De Souza, J. and Olmedo-Velarde, A. 2026. Characterization of a new closterovirus infecting Ficus carica. Virus Genes 62, 229–232. https://doi.org/10.1007/s11262-026-02216-z
5. Olmedo-Velarde, A., *Nakasato, K., Larrea-Sarmiento, A., Melzer, M. 2026. Viromics in Flat Mites from Hawaii Shows Abundant Arrays of Viruses, Expands the Evolutionary Origin of Plant Viruses, and Provides a Surveillance Tool for Brevipalpus-Transmitted Viruses. PhytoFrontiers (Online). https://doi.org/10.1094/PHYTOFR-06-25-0056-R

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45. Nicolas Aparicio Claros, Madalyn Shires, Dimitre Mollov, John Hammond, Ramon Jordan, Francisco Ochoa-Corona, Jennifer Olson, Kevin Ong, and Lina Rodriguez Salamanca. Rose Rosette Disease: A Diagnostic Guide. Plant Health Progress2022 23:4, 482-491. https://doi.org/10.1094/PHP-05-22-0047-DG
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58. Weiland, J. E., Garrido, P. A., Kamvar, Z. N., Espindola, A. S., Marek, S. M., Grünwald, N. J., and Garzón, C. D. 2017. Population structure of Pythium irregulare, ultimum, and P. sylvaticum in forest nursery soils of Oregon and Washington. Phytopathology 107:1404-1412.
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60. Blagden, T., Espindola, A. S., Cardwell, K. F., Ortega-Beltran, A., and Bandyopadhyay, R. 2019. Draft genome sequences of three isolates of Coniothyrium glycines, causal agent of red leaf blotch of soybean. Resour. Announc. 8:e00378-19.
61. Bocsanczy, A. M., Espindola, A. S., and Norman, D. J. 2019. Whole-genome sequences of Ralstonia solanacearum strains P816, P822, and P824, emerging pathogens of blueberry in Florida. Resour. Announc. 8:e00875-19.
62. Ochoa-Corona, F. M., Cardwell, K. F., and Espindola, A. S. 2019. New technologies from the microbial world: Alternatives for biomedical surrogate research. Biotechnol. Microbiol. 12(4):555844.
63. Espindola, A. S., Sempertegui-Bayas, D., Bravo-Padilla, D. F., Freire-Zapata, V. F., Ochoa-Corona, F. M., and Cardwell, K. F. 2021. TASPERT: Target-specific reverse transcript pools to improve HTS plant virus diagnostics. Viruses 13:1223.
64. Espindola, A. S., Cardwell, K. F., Martin, F. N., Hoyt, P. R., Marek, S. M., Schneider, W. L., and Garzón, C. D. 2022. A step towards validation of high-throughput sequencing for the identification of plant pathogenic oomycetes. Phytopathology 112:2044-2055.
65. Ramos-Lopez, D., Flores, F. J., and Espindola, A. S. 2025. MeStanG—Resource for high-throughput sequencing standard data sets generation for bioinformatic methods evaluation and validation. Biology 14:69.
66. Mosquera-Yuqui, F., Ramos-Lopez, D., Hu, X., Yang, Y., Mendoza, J. L., Asare, E., Habiger, J., Hurtado-Gonzales, O. P., and Espindola, A. S. 2025. A comparative template-switching cDNA approach for HTS-based multiplex detection of three viruses and one viroid commonly found in apple trees. Rep. 15:Article 86065.
67. Proaño-Cuenca, F., Carrera-Lopez, D., Zeller, K., Espindola, A. S., and Cardwell, K. F. 2025. Integrating in silico and in vitro approaches for detecting Coniothyrium glycines in high-throughput sequencing datasets using EDNA-MiFi®. PhytoFrontiers 5: (published online; page numbers not yet assigned).
68. *Ogando, T. L. and *Yuson, J. Distribution and serological relatedness of two tobamoviruses Infecting Plumeria spp. in Hawaiʻi. WERA-20 Meeting, May 7, 2026. Kahului, HI (Oral Presentation)
69. Ribeiro-Junior, M. R., Espindola, A., Nascimento, D. M., Barreto da Silva, F., Krause-Sakate, R., and Ochoa-Corona, F. M. 2025. An attempt toward the global screening of soybean viruses using EDNA-MiFi® based electronic probes. PhytoFrontiers 5: (published online; page numbers not yet assigned).
70. Sutton, M. 23 November 2025. Southeast Cold Hardy Expo. Let’s break the ice: growing cold hardy citrus. (oral presentation).
71. Sutton, M. 2 December 2025. Northeast ANR Update. Let’s break the ice: growing citrus in North Georgia. Crawford, Georgia. (oral presentation).
72. Sutton, M. 17 February 2026. Citrus Management Meeting. Common Physiological Issues. Valdosta, Georgia (oral presentation).
73. Sutton, M. 4 March 2026. ANR Foundations. UGA Citrus Extension Program. Tifton, Georgia. (oral presentation).
74. Sutton, M. 28 May 2026. Master Gardener Training. Growing Tree Fruits and Nuts. Quitman, Georgia. (oral presentation).