A MULTI-STATE EFFORT TO CONTAIN AND MANAGE THE INVASIVE GUAVA ROOT KNOT NEMATODE (GRKN) IN VEGETABLE CROPS

• Sponsoring Institution: National Institute of Food and Agriculture
• Project Status: COMPLETE
• Funding Source: OTHER GRANTS
• Reporting Frequency: Annual
• Accession No.: 1020264
• Grant No.: 2019-51181-30018
• Cumulative Award Amt.: $3,418,579.00
• Proposal No.: 2019-03136
• Project Start Date: Sep 1, 2019
• Project End Date: Aug 31, 2024
• Grant Year: 2019
• Program Code: [SCRI]- Specialty Crop Research Initiative

Recipient Organization
CLEMSON UNIVERSITY
(N/A)
CLEMSON,SC 29634

Performing Department
(N/A)

Non Technical Summary
The emergence of Guava Root-Knot Nematode (GRKN,Meloidogyne enterolobii), a highly virulent root-knot nematode (RKN) species, is potentially devastating to specialty crop production in the southeastern United States. This pest causes significant losses in yield and quality, and its quarantined status jeopardizes both interstate and international trade. A major concern is the ability of GRKN to infect and damage crop genotypes that are resistant to the other major species of RKN, including sweetpotato, cucumber, watermelon and tomato. New resources and information are urgently needed to help farmers manage this aggressive and polyphagous pest. Our goal is to reduce the vulnerability of growers to the emerging agricultural threat posed by GRKN. Our interdisciplinary team will achieve this goal using a systems-based approach involving five interconnected research and extension objectives: 1) Study the prevalence and distribution of GRKN in vegetable crops in the Southeast, and characterize the genetic variability encountered; 2) Evaluate and develop vegetable germplasm with resistance against GRKN; 3) Evaluate the efficacy of nematicides, cover crops, and rotations as management strategies for GRKN; 4) Assess the costs and returns of rotations, cover crops, and nematicides for the management of GRKN on sweetpotato, cucumber, watermelon and tomato crops; 5) Develop print and web-based educational materials on management and containment strategies for GRKN. Our proposal contributes to the following program goals: identifying and addressing threats from pests and diseases; and research on plant breeding, genetics, and genomics for pest and disease management.

Animal Health Component

50%

Research Effort Categories

Basic

30%

Applied

50%

Developmental

20%

Classification

Knowledge Area (KA)	Subject of Investigation (SOI)	Field of Science (FOS)	Percent
212	1499	1120	100%

Knowledge Area
212 - Pathogens and Nematodes Affecting Plants;

Subject Of Investigation
1499 - Vegetables, general/other;

Field Of Science
1120 - Nematology;

Keywords

root-knot nematode

meloidogyne enterolobii

cucurbits

sweetpotato

resistance

nematicide

Goals / Objectives
This project addresses a gap in knowledge in the distribution of Guava Root-knot Nematode (GRKN) and sources of plant resistance used to manage the nematode. At the completion of these studies, we expect to provide knowledge regarding the distribution and diversity of GRKN, identify previously unknown sources of resistance to this pest, evaluate the efficacy of rotations, cover crops, and nematicides as management strategies for GRKN, assess the costs and returns of rotations, cover crops, and nematicides for the management of GRKN, and provide print and web-based materials regarding management/containment strategies for GRKN.The long term goal of our research is to enhance the resiliency of vegetable production by integrating management practices and information that help growers anticipate and respond to the threat that the spread of GRKN poses to high quality crops in the U.S. and around the globe.

Project Methods
The present project significantly complements existing programs. Our project will capitalize on research and extension programs in vegetable pathology, nematology, genetics, genomics, phenomics, and horticulture.Extension and outreach.The project team will develop content for extension and outreach. These materials will be disseminated by publishing in refereed journals, trade magazines, electronic publications, participation in vegetable field days across the southern U.S., various state vegetable and crop associations annual conferences, regional seminars, and national/international scientific meetings. Information regarding the progress and impact of the outreach plan will be supported with systematic evaluation by the Project Manager with input from the Industry Advisory Panel.Germplasm phenotyping.GRKN phenotyping of target species will be started in year 1 and continue through year 4. This effort will be led by co-PDs Rutter and Wadl through supervision of Postdoctoral Scientist and Research Technician to be hired on the project. The technician will maintain and assist in data collection, whereas the Postdoctoral Scientist will establish image analysis protocols in collaboration with Phenospex.Mapping of GRKN resistance.GWAS for GRKN resistance will start in year 3 as finalized phenotyping data becomes available, and will continue through year 4. This effort will be led by co-PDs Rutter (pepper and cucurbits) and Wadl (sweetpotato) through supervision of the Postdoctoral Scientist. There will be close collaboration with Bode Olukolu (University of Tennessee; see collaboration letter) who will provide genotype data and analysis pipelines. This project will provide phenotype data for GWAS.Germplasm improvement.Germplasm identified as resistant to GRKN will be used for designing crosses for introgression into breeding lines for cucumber, pepper, sweetpotato, and watermelon. This effort will be led by co-PDs Rutter and Wadl through supervision of Postdoctoral Scientist and Research Technician to be hired on the project. The technician will execute the crosses (plant and seed maintenance) designed by Rutter, Wadl, and Postdoctoral Scientist. Sweetpotato crosses will begin in year 1 and continue through year 4, and crosses for additional vegetable crops will commence as other sources of resistance are identified.Economic analyses.To evaluate the on-farm economic viability of management practices, information on costs and yields from research experiments and stakeholders will be utilized. All analyses will be conducted under the guidance of Guan in Florida. Any assumptions utilized will be validated with experts on the project team.The general objectives are to search for the presence of GRKN in the southeast United States (the Carolinas, Florida, Georgia), to screen accessions of cucurbit (cucumber and watermelon), pepper and sweetpotato germplasm for resistance, and to demonstrate that GRKN can be managed and contained efficiently and effectively.The objectives (with hypotheses) and sub-objectives are:Objective 1. Study the prevalence and distribution of GRKN in vegetable crops in the Carolinas, Florida and Georgia; and characterize the genetic variability encountereda. Identify potential pathways of dissemination of the pathogen.b. Determine vegetable crops at risk of GRKN infection and weeds that could serve as a green bridge for this nematode.c. Study the genetic structure and haplotype diversity of the populations recovered.d. Provide baseline data for species potential for adaptation to selection pressures.e. Provide insight into the effective use of host resistance as a management strategy.Hypothesis: Genetically diverse populations of GRKN are present in vegetable fields in the Carolinas, Florida and Georgia.Objective 2. Evaluate and develop vegetable germplasm with resistance against GRKN.f. Identify sources of GRKN resistance in susceptible vegetable crops by screening representative core sets of PI lines from the USDA-GRIN germplasm collections of sweetpotato, pepper, watermelon, and cucumber.g. Develop high throughput root phenotyping tools and methodologies that can be used to assist and accelerate efforts to breed GRKN resistant vegetable cultivars.h. Map GRKN resistance genes and develop markers that can be used to accelerate the ingression of resistance into new resistant vegetable germplasm with favorable agronomic traits that can help manage this pest.i. Develop new GRKN resistant germplasm through controlled crosses.Hypothesis: The available GRKN resistance in vegetable germplasm is controlled by mappable genes that can be identified using traditional genetic techniques combined with high throughput genotyping methodologies.Objective 3. Evaluate the efficacy of rotations, cover crops, and nematicides as management strategies for GRKNj. Evaluate chemical control options (fumigant and non-fumigant nematicides)k. Examine the impact of cover crops antagonistic to Meloidogyne spp. in sweetpotato rotational crops including, but not limited to: Sunn Hemp, Oilseed Radish, and Winter Rye.l. Assess the impact of management of nematodes in rotational crops on GRKN populations in vegetable crops.m. Evaluate containment and sanitation measures to prevent further spread and minimize impact.Hypothesis: For each of the selected vegetable crops, at least one management strategy will effectively reduce nematode populations in the field.Objective 4. Assess the costs and returns of rotations, cover crops, and nematicides for the management of GRKN on sweet potato, cucumber, watermelon and tomato crops.n. Perform an assessment of economic risk to vegetable growers in the region.o. Estimate the costs and returns for implementing the management strategies in Objective 3.p. Assess the economic impact of quarantine measures for GRKN.Hypothesis: For each of the selected vegetable crops, at least one management strategy of GRKN is cost-effective.Objective 5. Develop print and web-based materials to disseminate suggested management/containment strategies for GRKN.q. Translate findings into solutions for stakeholders in user-friendly formats.r. Share research findings with stakeholders through extension publications and communication during grower meetings and field days.Hypothesis: Educational materials will increase adoption of scientifically-based, cost-effective containment/management strategies.

Progress 09/01/19 to 08/31/24

Outputs
Target Audience:The target audiences reached by our efforts during this reporting period were farmers, breeders, germplasm curators, extension specialists and agents, university collaborators, USDA collaborators, and our advisory board. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?NCSU: Faculty, technicians, postdocs, graduate students, and undergraduate students have received training in nematode biology and management through this project. Some personnel in our groups that are not directly supported by the project have also benefited and learned from the activities performed in our programs. Early-career scientists from underrepresented backgrounds have been effectively engaged in the project. USDA-ARS: Two post-docs (Dr. Catherine Wram and Dr. Homan Regmi) developed professionally by conducting experiments, collecting and analyzing data, and ultimately publishing manuscripts related to this project. Dr. Wram also obtained a permanent nematology position at USDA-ARS during this project. UF: Dr. Chang Liu's experience as a bioscientist on this project with Dr. Grabau helped her earn an Assistant Professor position at Mississippi State University. Similarly, Dr. Rebeca Sandoval-Ruiz's experience on this project as a post-doc with Dr. Grabau helped her earn an Assistant Professor position at the University of Costa Rica Gabrieli Riva (grad student, M.e. survey results). Gabrieli was an MS student funded by this project, and graduated in August 2023 (thesis title: Identification, Distribution and Hosts of Root-Knot Nematodes (Meloidogyne Spp.) in Florida, USA with Focus on Meloidogyne enterolobii. Also, the following student interns were trained and were involved with the FindMe project: Marian Mendez, BSc, Zamorano University, Honduras, 1/24-4/24 Tawonga Zakeyu, BSc, Earth University, Costa Rica, 1/23-12/23 Tariq Adnan, PhD student, PMAS-Arid Agric. Univ. Rawalpindi, Pakistan, 2/23-8/23 Asma Mahek, PhD student, PMAS-Arid Agric. Univ. Rawalpindi, Pakistan, 1/23-6/23 Letitia Lopes De Paula, PhD student, UFLA, Lavras, Brazil, 6/22-5/23 Tennyson Nkhoma, BSc, Earth University, Costa Rica, 9/2022-12/2022 Julio Peres, BSc, Vicosa University, Brazil, 2/2022-12/2022 Ashley Chisholm, BSc, University of Florida, 5/2021-8/2021 Laura Mayorga, BSc, Universidad Nacional, Colombia, 4/2021-10/2021 How have the results been disseminated to communities of interest?NCSU: We have presented results from this project to stakeholders at several extension venues such as the annual North Carolina Sweetpotato field day, the Organic Commodities and Livestock Conference, field days, Southeast Vegetable and Fruit Expo, Winter Vegetable Conference, and regional crop production meetings. We have also presented at scientific conferences such as the Annual Southern Division American Phytopathological Society Meeting, the American Phytopathological Society Annual Meeting, and the Society of Nematologists Annual Meeting. USDA-ARS: We published the results of our new method for screening sweetpotato storage roots for M.e. to the peer-reviewed journal Crop Protection. We presented the results of this work at the international Procinorte Workshop organized by the Inter-American Institute for Cooperation on Agriculture, as well as at the annual Society of Nematologists meeting. The release of the M.e. resistant sweetpotato line USDA-10-185 was publicized by USDA-ARS through their Tellus video series: Developing Sweetpotatoes That Are Fit to Fight Pests Tellus (usda.gov) CU: Both print and web based materials were distributed through various field days throughout SC. Furthermore, project updates and results were distributed through our X account (https://x.com/FINDMeNematode) and our project website (https://www.findmenematode.org/). The twitter account has increased its followers to 322 and the website has received over 2,500 page views this year. What do you plan to do during the next reporting period to accomplish the goals? Nothing Reported

Impacts
What was accomplished under these goals? Obj 1. Surveys for M.e. were continued using samples submitted by county agents, consultants, and individual growers. The focus was on vegetable, cotton and soybean samples exhibiting significant levels of galling. One-hundred ninety-five samples were submitted from 12 counties in South Carolina. Results of the Florida survey as reported previously, provide new insights into the distribution, prevalence, and hosts of root-knot nematodes in Central and South Florida. It is evident that M. enterolobii is much more common in Florida soils than previously thought. Between October 2019 to February 2022, a total of 23 crops from 222 fields across 39 counties of Georgia were sampled. Samples were submitted by University of Georgia Extension agents.Tattnall County is in the heart of Georgia's world-renowned Vidalia Onion region. Thus, this nematode species can become a major threat to this vital industry. Consequently, we conducted a greenhouse investigation spanning two months, commencing on February 5th, in Tifton, GA.Quesada and Gorny published a manuscript describing the susceptibility of 18 hosts to a North Carolina population of M. enterolobii. Obj 2. USDA-ARS initiated the release of a new M. e. resistant sweetpotato breeding line 'USDA 10-185'. We also phenotyped additional sweetpotato PI lines and advanced clones from our breeding program for M.e. resistance. The data from these screens will be used to conduct a Genome Wide Association Scan (GWAS) to identify genomic loci associated with M.e. resistance in sweetpotato. We developed a biparental sweetpotato population between 'Regal' (M.e. resistant) and 'Beauregard' (M.e. susceptible) and have phenotyped about 75 individuals from this population. This population will be used for detection of QTLs associated with M.e. resistance. Two manuscripts are in preparation describing M.e. resistant sweetpotato germplasm from accession originating from Asia, the Caribbean, Central and South America. Breeding nurseries were established and seed was harvested in each year of the project, and we expect to identify new M.e. resistant germplasm as we continue evaluating advanced sweetpotato clones. We successfully phenotyped a pepper F2 population, developed from a cross between the M.e. resistant pepper line 'PMER-2' and 'Charleston Belle'. We collected and sequenced DNA from the twenty F2 individuals that showed the most extreme resistant and susceptible phenotypes. The results from this sequencing are being used to conduct a bulk segregant analysis to identify genomic regions associated with resistance to M.e. in pepper. Seed was also collected from the most resistant F2s to facilitate future resistance breeding efforts. Obj 3. Three trials were conducted in 2019 (Meadow, Bailey, and Pinceton, NC) and one in 2020 (Stancil's Chapell, NC) by Quesada in collaboration with Gorny to evaluate chemical and host resistance control options for M. enterolobii in sweetpotato. All sites were confirmed to be infested with M. enterolobii using molecular diagnostics prior to setting up field trials and nematode counts per plot were taken before, mid-way, and at the end of each trial. The sites in Bailey and Princeton had variable nematode counts with the non-treated control showing very low nematode pressure. The site in Meadow had more uniform nematode pressure that allowed successful analysis of treatment effects. The Meadow trial showed significant control of M. enterolobii by Telone II + Velum Prime (current grower recommendation) and K-PAM. In addition, varieties 'Murasaki 29' and 'Jewel' showed lower nematode damage than the variety 'Covington'. The trial in Stancil's Chapell is ongoing and results will be provided in the next reporting period. Three nematicide trials were completed in 2023 by Gorny at the GRKN Research Site at the Border Belt Tobacco Research Station in Whiteville, NC. The first trial evaluated non-fumigant nematicides for control of M.e. in sweetpotato. Chemical treatments in this trial included Velum Prime (fluopyram) at 6.5 fl oz/ac, Vydate (oxamyl) at 128 fl oz/ac, Majestene (biologial) at 6 qt/ac, AzaGuard (azadirachtin) at 15 fl oz/ac, Salibro (fluazaindolizine) at 30.7 and 61.3 fl oz/ac, and non-treated controls. The second trial evaluated in-furrow nematicides for control of M.e. in cotton. Chemical treatments in this trial included Velum (fluopyram) at 6.5 fl oz/ac, Majestene (biological) at 6 qt/ac, and non-treated controls. The third trial evaluated in-furrow nematicides for control of M.e. in soybean. Chemical treatments in this trial included Velum Prime (fluopyram) at 3, 4, 5, and 6 fl oz/ac, Majestene (biological) at 6 qt/ac, MeloCo WG (biological) at 9 lbs/ac, AzaGuard (azadiractin) at 15 fl oz/ac, and non-treated controls. In the last year we evaluated the following biological products: NemaClean, Double Nickle and Nemakill, and the chemicals Velum, Vydate and Salibro. Overall, in the greenhouse trials the chemical nematicides were more consistent in reducing root gall rating or nematode egg number. Biological products rarely showed reductions in root gall rating, but they did show a reduction in nematode egg number. In our most recent experiments, we evaluated combinations of biologicals and these treatments showed to be more effective than each biological by itself (see publication # 3). Obj 4. The research team 1) conducted a partial budget analysis of tomato production in Florida to determine if the non-fumigant nematicides used in the field trials are cost-effective compared to fumigation treatments, and 2) explored impacts of market fluctuations through a sensitivity analysis. Using three years of experimental data on Florida tomatoes, the team found that 1) In spring, treatments effects vary, and the cost-effectiveness of the three treatments is inconsistent across years; 2) Fumigation treatments (fumigation only as well as the combination of fumigation and nematicides) are consistently cost-effective relative to control only in fall (with fumigation only increasing return by $5587 per acre and fumigation plus nematicides increasing return by $5019 per acre relative to control) but not in Spring; 3) Non-fumigant nematicides application is more beneficial in spring, increasing return by $2410 per acre compared to not applying nematicide, and by $1146 per acre in fall. Our sensitivity analysis results suggest that optimal treatments also depend on tomato market prices and treatment costs. Obj 5. Develop print and web-based materials. Both print and web-based materials were distributed through various field days throughout SC. Furthermore, project updates and results were distributed through our X account (https://x.com/FINDMeNematode) and our project website (https://www.findmenematode.org/). The twitter account has increased its followers to 322 and the website has received over 2,500 page views this year. Quesada provided diagnostics and disease management recommendations for 501 vegetable crop samples submitted in the reporting period to the NC State Plant Disease and Insect Clinic. Quesada has also been involved in providing disease management recommendations through oral presentations, social media (Twitter: 7,686 (lab) + 4,188 (Quesada) followers, LinkedIn: 3,515 followers. Gorny has been involved with providing nematode biology and management information through direct recommendations to growers and agents, and oral presentations.

Publications

• Type: Peer Reviewed Journal Articles Status: Published Year Published: 2024 Citation: Schwarz, T., Chitra, Jennings, K., and Gorny, A.M. 2024. Evaluation of weed species for host status to the root-knot nematodes Meloidogyne enterolobii and M. incognita race 4. Journal of Nematology 56:20240017.
• Type: Peer Reviewed Journal Articles Status: Published Year Published: 2024 Citation: Wong, TW. S., Ye, W., Thiessen, L.D., Huseth, A.S., Gorny, A.M., and Quesada-Ocampo, L.M. Occurrence and distribution of Meloidogyne spp. in fields rotated with sweetpotato and host range evaluation of a North Carolina population of Meloidogyne enterolobii. 2024. Plant Disease. PMID: 38736152
• Type: Peer Reviewed Journal Articles Status: Published Year Published: 2024 Citation: Grunwald N. J., Bock C. H., Chang J. H., Alves De Souza A., Del Ponte E. M., du Toit L. J., Dorrance A. E., Dung J., Gent D., Goss E. M., Lowe-Power T. M., Madden L. V., Martin F. M., McDowell J., Naegele R. P., Potnis N., Quesada-Ocampo L. M., Sundin G. W., Thiessen L., Vinatzer B. A., and Zeng Q. (2024) Open access and reproducibility in plant pathology research: guidelines and best practices. Phytopathology: PMID: 38330057
• Type: Peer Reviewed Journal Articles Status: Published Year Published: 2024 Citation: Lopes de Paula L, Campos VP, Terra WC, de Brum D, Jacobs D, Bui H, Desaeger J (2024). The combination of Bacillus amyloliquefaciens and Purpureocillium lilacinum in the control of Meloidogyne enterolobii, Biological Control 189: 9 pp.
• Type: Peer Reviewed Journal Articles Status: Published Year Published: 2024 Citation: Coburn J and Desaeger J (2024). Host status and susceptibility of Cannabis sativa cultivars to root-knot nematodes. Journal of Nematology 56 (1): 14 pp.
• Type: Peer Reviewed Journal Articles Status: Published Year Published: 2024 Citation: Wong TW. S.S and Quesada-Ocampo L. M. (2024) Sensitivity of Meloidogyne incognita, Fusarium oxysporum f.sp. niveum, and Stagonosporopsis citrulli to succinate dehydrogenase inhibitors used for control of watermelon diseases. 2024. Plant Disease 2024 108:6, 1762-1768

Progress 09/01/22 to 08/31/23

Outputs
Target Audience:The target audiences reached by our efforts during this reporting period were farmers, breeders, germplasm curators, extension specialists and agents, university collaborators, USDA collaborators, and our advisory board. Changes/Problems: Nothing Reported What opportunities for training and professional development has the project provided?NCSU: Faculty, technicians, postdoctoral associates, graduate students and undergraduate students have received training and learned new skillsets in nematology, statistical analysis, and field plant pathology through this project. Early-career scientists from underrepresented backgrounds have been effectively engaged in this project. USDA-ARS: A post-doc (Dr. Catherine Wram) and a master's student (Julianna Culbreath) developed professionally by conducting experiments, collecting and analyzing data, and ultimately publishing manuscripts related to this project. CU: Surveys on small sweetpotato farms on 17 November 2022, with one-on-one visits with 5 minority sweetpotato growers in Marion County. September 5, 2023 Dr. Mueller took 6 Ph.D. students enrolled in his class "Detection and Management of Row Crop Nematodes" to the ARS-USVL in Charleston where Dr. Rutter and his lab provided training in identifying damage from M. enterolobii in sweetpotato, evaluating resistance to M. enterolobii in pepper germplasm, and greenhouse culturing of M. enterolobii on various host crops. How have the results been disseminated to communities of interest?NCSU: During this reporting period, we have presented results and findings from this project to stakeholders at the 2022 North Carolina Sweetpotato Field Day (Kinston, NC; Oct 13, 2022), the 2022 Southeast Fruit and Vegetable Expo (Durham, NC; Nov 29, 2022), and the 2022 Certified Crop Advisor Training Day (Smithfield, NC; Dec 6, 2022). We have also presented results and engaged in scientific discussion at the including the Southern Division American Phytopathological Society Meeting, American Phytopathological Society Annual Meeting, and the Society of Nematologists Annual Meeting. USDA: We published the results of our watermelon GWAS study in the peer-reviewed journal Plant Disease. We also submitted a manuscript describing our new method for screening sweetpotato storage roots for M.e. to the peer-reviewed journal Crop Protection. We hosted a visiting scientist from Mississippi State University and trained him on our new methods for surveying for the presence of M.e. in sweetpotato storage roots. Presented results of the project at the Edisto Research and Education Center's Fall Vegetable Field Day and at Rutgers University Plant Breeding Graduate Seminar Course. CU: Presentations that included information on M. enterolobii were given to growers at 5 county/area meetings, 2 "class related" activities and 1 on-farm demonstration USDA-ARS: We disseminated information on the threat posed by M.e. and project results during three field days hosted by Clemson University at their Costal, Edisto, and PeeDee Research and Education Centers. What do you plan to do during the next reporting period to accomplish the goals?NCSU: Quesada and Gorny will continue field experiments to evaluate chemical management options for M.e. Quesada and Gorny will continue efforts to disseminate findings of this project to stakeholders through Extension modes and academic discussion. CU: We will continue surveying for M. enterolobii in sweetpotato and other vegetable production fields as well as cotton and soybean fields. We will produce printed information sheets (a Land Grant Press article) on M. enterolobii focusing on South Carolina. Create a "Meloidogyne enterolobii field isolation site" at the Edisto REC where extensive field screening of sweetpotato, pepper, watermelon and cucurbit germplasm can be evaluated in the field for resistance and/or tolerance to M. enterolobii.

Impacts
What was accomplished under these goals? Obj 1. CU: We collected samples from 47 fields exhibiting galling from root-knot nematode, most on soybean. Samples were determined to be either Meloidogyne incognita or Meloidogyne arenaria. No samples were determined to be Meloidogyne enterolobii USDA: We developed a new method for screening batches of sweetpotato storage roots for the presence of M.e. and used this method to conduct a survey fresh market sweetpotatoes from SC, NC, AR, and MS. We detected root knot nematodes in 12 of the 30 batches surveyed, and found that 3 of these positive batches contained M.e. UF: Soil and root samples were collected from 56 crops cultivated in commercial vegetable and fruit farms, research farms, horticultural gardens, Asian vegetable farms, and natural landscapes in 12 counties. RKN were detected in 247 out of 304 (81.25%) root samples . Five RKN (M. arenaria, M. enterolobii, M. hapla, M. incognita and M. javanica) were identified. M. incognita and M. enterolobii were the most prevalent species, each present in 76 (25.00%) of the samples. Mixed populations of M. enterolobii and M. incognita were identified in 4 (1.31%) samples. Phylogenetic analysis showed low genetic variability among populations of Mefound in Florida and the USA. New records include: a worldwide host record, Solanum capsicoides; continental USA host records, Vigna unguiculata, Opuntia cochenillifera, and state host record forPhaseolus vulgaris.It is evident that Meis much more common in Florida soils than previously thought. UGA: Asoil survey of 23 vegetable crops resulted in Medetected in Tattnall and Lowndes County. Tattnall County is in the heart of Georgia's world-renowned Vidalia Onion region. Thus, this nematode species can become a major threat to this industry. We conducted a preliminary greenhouse investigation including five commercialonion varieties (Macon, Sweet Magnolia, Candy Joy, 1407, and Early Sweet). The results revealed that all the tested onion varieties were susceptible with no statistically significant differences. This underscores the importance of further trials involving additional onion varieties, which could inform recommendations. NCSU: Gorny completed screening of resistance in eggplant and tomato germplasm. In the greenhouse, 56 unique lines of eggplant were screened, with7 lines displayingresistance. Also in the greenhouse, 31 lines of tomato were screened for resistance to M.e. Fourlines displayed high resistance, and several more showed moderate resistance. Quesada evaluated 18 hosts and Mewas able to reproduce on all. Two watermelon varieties, cabbage, pepper, one soybean variety, and tobacco were significantly susceptible. Broadleaf signalgrass, corn, one peanut variety, sudangrass, and nutsedge were considered poor hosts. Obj 2. USDA-ARS: We phenotyped and collected seed from 110 plants from biparental mapping populations originating from a cross between the M.e. resistant pepper line 'PMER-2' and 'Charleston Belle'. We sequenced and assembled two high quality genomes for both parental genotypes that will facilitate mapping of the M.e. resistance trait. We phenotyped a diversity panel of 89 sweetpotato PIs for resistance to M.e. which will facilitate a Genome Wide Association Scan (GWAS) to identify genomic loci associated with resistance. Established two breeding nurseries to introgress M.e. resistance into new sweetpotato germplasm. From the breeding nurseries, over 7,500 seedlings were grown in the field and 150 individuals were selected for desirable root traits (yield, consistency of shape, flesh and skin color, etc.). Obj 3. NCSU: One fumigant nematicide trial was completed in 2022 by Gorny at the GRKN Research Site at the Border Belt Tobacco Research Station in NC. The quarantined site has been inoculated with M.e. to establish a population and had a moderate level of M.e. at the time the trial was conducted. Chemical control treatments in this trial included Metam CLR (metam sodium) fumigant at two different rates (45 and 75 gal/Ac), Velum Prime (fluopyram) at 6.5 fl oz/Ac, and non-treated control plots. Soil samples for nematode analysis were collected from each plot prior to fumigant treatment, at planting, and at harvest. All the chemical treatments resulted in an increased marketable yield compared to the non-treated control; however the differences were not all statistically significant. Results of this chemical control trial were used in recommendations for producers. UF: Six different strawberry cultivars were screened for their M.e. host status and all cultivars were non-hosts (no M.e. reproduction was noted). Efficacy of different nematicides against M.e on cucumber was done in the greenhouse and in farmer's fields in Hillsborough County, FL, that were positive for M.e. (pepper and Asian vegetables). Results are still being analyzed, but one Asian vegetable grower who never had applied nematicides before, noticed that after applying nematicide (Velum or MeloCon) he was able to harvest his jute crop 7 times instead of four times in the past. Obj 4. UF: We conducted a partial budget analysis of tomato production in Florida and explore market fluctuations impact through a sensitivity analysis. Using three years of data from experiments in Wimauma, Florida, we found that while fumigation in the fall is cost-effective--yielding a net profit gain compared to non-fumigation treatment--it is not advised for the spring, as it could lead to a significant loss of $1,926 per acre. Nematicides prove beneficial in Spring, enhancing yields and profitability even if preceded by fumigation. The optimal treatment choice to secure the highest profitability depends on the combination of tomato sale prices and treatment expenses. A price/cost fluctuation of ±10% or more could alter the optimal choice. Obj 5. CU/USDA: Print and web based materials were distrubuted through field days throughout SC. Project updates and results were distributed through our twitter account (https://twitter.com/FINDMeNematode) and our project website (https://www.findmenematode.org/). The twitter account has increased its followers to 322. NCSU: During the reporting period, Quesada provided diagnostic and disease management recommendations for 78 vegetable crops samples submitted to the NC State Plant Disease and Insect Clinic. Quesada has also been involved in providing disease management recommendations through oral presentations, social media (Twitter: 7,142 (lab) + 3,874 (Quesada) followers, LinkedIn: 3,106 followers). During the reporting period, Gorny has provided M.e. biology and management information through direct recommendations to vegetable growers and agents (n= 51 individual phone, email, or in-person consultations) and oral extension presentations (n = 8). Quesada and Gorny have presented results as oral talks or posters at scientific conferences, including the Southern Division American Phytopathological Society Meeting, American Phytopathological Society Annual Meeting, and the 2022 and 2023 Society of Nematologists Annual Meetings. During the reporting period, Quesada and Gorny published 6 Plant Disease Management Reports regarding management of M.e. on crops outlined in this proposal. UF: Results were presented at SON 2023 meeting in Columbus, Ohio by Gabrieli Riva (grad student, M.e. survey results). Gabrieli was an MS student funded by this project, and she just graduated in August (thesis title: Identification, Distribution and Hosts of Root-Knot Nematodes (Meloidogyne Spp.) in Florida, USA with Focus on Meloidogyne enterolobii. Updates on M.e work were also given at grower's meetings (FL Ag expo, November 2022, Wimauma, FL; Strawberry grower's meeting, April 2023, Plant City FL; Florida Citrus and Vegetable Expo, September 2023, Tampa, FL; Tomato grower's meeting, September 2023, LaBelle, FL).

Publications

• Type: Book Chapters Status: Published Year Published: 2023 Citation: Salcedo A., Parada-Rojas C. H., Guerrero R., Stahr M., DArcangelo K.N., McGregor C., Kousik C., Wehner T., and Quesada-Ocampo L. M. (2023) The NLR family of disease resistance genes in cultivated watermelon and other cucurbits: opportunities and challenges. Chapter 4. In: The Watermelon Genome. Editors: Dutta S. K. and Reddy U. Springer.
• Type: Book Chapters Status: Published Year Published: 2022 Citation: Egel D., Adkins S., Wintermantel B., Keinath T., DArcangelo K., Parada-Rojas C. H., Rennberger G., Toporek S., Hausbeck M., and Quesada-Ocampo L. (2022) Diseases of cucumbers, melons, pumpkins, squash, and watermelons. In: Handbook of Plant Disease Management. Handbook of Vegetable and Herb Diseases. Editors: Elmer W., McGrath M. T., and McGovern R. Springer.
• Type: Journal Articles Status: Accepted Year Published: 2024 Citation: Wong, TW. S., Ye, W., Thiessen, L.D., Huseth, A.S., Gorny, A.M., and Quesada-Ocampo, L.M. Occurrence and distribution of Meloidogyne spp. in fields rotated with sweetpotato and host range evaluation of a North Carolina population of Meloidogyne enterolobii. Plant Disease [accepted with revision].
• Type: Journal Articles Status: Accepted Year Published: 2024 Citation: Schwarz, T. and Gorny, A.M. 20XX. Evaluation of Soybean Genotypes (Glycine max and Glycine soja) for Resistance to the Root-Knot Nematode, Meloidogyne enterolobii. Plant Disease [accepted with revision].
• Type: Journal Articles Status: Published Year Published: 2023 Citation: Waldo, B., Branham, S., Levi, A., Wechter, W., & Rutter, W. B. (2023). Distinct genomic loci underlie quantitative resistance to Meloidogyne enterolobii galling and reproduction in Citrullus amarus. Plant Disease, 107(7), 2126-2132. Doi: 10.1094/PDIS-09-22-2228-RE
• Type: Journal Articles Status: Published Year Published: 2022 Citation: Soto-Caro, A., Luo, T., Wu, F., & Guan, Z. (2022). The US sweet potato market: Price response and impact of supply shocks. Horticulturae, 8(10), 856. https://doi.org/10.3390/horticulturae8100856
• Type: Conference Papers and Presentations Status: Published Year Published: 2022 Citation: Agudelo P., Corbin J., Desaeger J., Gorny A., Grabau Z., Guan Z., Hajihassani A., Mueller J., Quesada-Ocampo L. M., Rutter W., and Wadl P. (2022) Multi-state effort to contain and manage Meloidogyne enterolobii on vegetable crops. Phytopathology 112: S3.69.
• Type: Conference Papers and Presentations Status: Published Year Published: 2022 Citation: Parada-Rojas C. H., Pecota K., Almeyda C., Yencho G. C., Childs K., and Quesada-Ocampo L. M. (2022) Unveiling NLR gene diversity in hexaploid sweetpotato cultivars. Phytopathology 112: S3.18.
• Type: Other Status: Published Year Published: 2022 Citation: Jeffreys, P.B., Grode, A., and Gorny, A.M. (2022) Variety and in-furrow nematicide treatments for suppression of Meloidogyne enterolobii in soybean in North Carolina, 2021. Plant Disease Management Reports. 16: N021.
• Type: Other Status: Published Year Published: 2022 Citation: Jeffreys, P.B., Grode, A., and Gorny, A.M. (2022) Evaluation of fumigant and non-fumigant nematicides for management of root-knot nematode in sweetpotato in North Carolina, 2021. Plant Disease Management Reports. 16: N023
• Type: Other Status: Published Year Published: 2022 Citation: Jeffreys, P.B., Grode, A., and Gorny, A.M. (2022) Control of root-knot nematode in bell pepper and cucumber using Telone II fumigant and Velum Prime, 2021. Plant Disease Management Reports. 16:N024.
• Type: Other Status: Published Year Published: 2023 Citation: Jeffreys, P.B., Dotray, J., and Gorny, A.M. (2023). Suppression of Meloidogyne enterolobii in cotton using in-furrow nematicides, 2022. Plant Disease Management Reports. 17:N052
• Type: Other Status: Published Year Published: 2023 Citation: Malter, V., Jeffreys, P.B., Dotray, J., and Gorny, A.M. (2023). Evaluation of metam sodium fumigant nematicide for management of Meloidogyne enterolobii in sweetpotato in North Carolina, 2022. Plant Disease Management Reports. 17: N051
• Type: Websites Status: Published Year Published: 2023 Citation: Website: https://www.findmenematode.org/ Twitter: https://twitter.com/FINDMeNematode

Progress 09/01/21 to 08/31/22

Outputs
Target Audience:The target audiences reached by our efforts during this reporting period were farmers, breeders, germplasm curators, extension specialists and agents, university collaborators, USDA collaborators, and our advisory board. Changes/Problems:Progress in some objectives has been delayed due to coronavirus-related restrictions but we are making good progress towards objective completion, and we do not expect any issues in performing project activities as proposed. The USVL and USDA-ARS was shut down due to the COVID 19 pandemic on March 31st, 2020. The agency remained at reduced building occupancy restrictions until May 28th, 2022. These restrictions made it difficult for us to obtain and screen all the germplasm we originally planned. With the building restrictions now lifted we have already begun to significantly increase the number of screens we are performing for this project. What opportunities for training and professional development has the project provided?TRAINING OPPORTUNITIES NCSU: Faculty, technicians, postdocs, graduate students, and undergraduate students have received training in nematode biology and management through this project. Some personnel in our groups that are not directly supported by the project have also benefited and learned from the activities performed in our programs. Early-career scientists from underrepresented backgrounds have been effectively engaged in the project. USDA-ARS: A post-doc (Dr. Benjamin Waldo) was hired to perform the M. e. screening experiments at the USVL and had the opportunity to begin screening watermelon and sweetpotato. A master's student (Julianna Culbreath) helped to set up the screening experiments for both pepper and sweetpotato, and is working to develop the new storage root survey method for M.e. CU: One-on-one training sessions were held with Zack Snipes (Charleston area Hort. agent), Justin Ballew (Lexington Commercial Hort. Agent), Rob Last (Savannah Valley Hort. agent), and Phillip Carnley (Orangeburg Area Commercial Hort. Agent). Did one-on-one in-field trainings with Agronomic row crop agents Jonathan Croft (Orangeburg & Dorchester Counties), Jay Crouch (Newberry & Saluda Counties), Steven Crowder (Allendale & Hampton Counties), and Hannah Mikel (Clarendon & Sumter Counties), One-on-one training sessions in-the-field were held with Crop Consultants Jerry Adams (Lee County area) and Fleming McMaster (Upper Savannah Valley area). UF: The bioscientist on this project learned to identify root-knot nematode species using PCR-based molecular techniques. Gaining experience with molecular techniques is something they identified as an important part of their professional training. Student training and postdoc professional development was also provided. New MS student was trained in molecular id of M.e. UGA: A MSc student (Gema Nugraha) and a Postdoc (Banani Mondal) were hired to work on molecular detection of root-knot nematodes. How have the results been disseminated to communities of interest?DISSEMINATION OF RESULTS NCSU: We have presented results from this project to stakeholders at several extension venues such as the annual North Carolina Sweetpotato field day, the Organic Commodities and Livestock Conference, field days, and regional crop production meetings. We have also presented at scientific conferences such as the Annual Southern Division American Phytopathological Society Meeting, the American Phytopathological Society Annual Meeting, and the Society of Nematologists Annual Meeting. CU: Survey results and the damage potential of M.e. were presented to growers, agents, and industry personnel at the S.C. State Cotton meeting (125+ attendees), the Savannah Valley Cotton Production Meeting (75 attendees), Edisto REC Fall Field Day (50 attendees), the 2019 Certified Crop Advisors training meeting (30 attendees) and to meetings of the S.C. Cotton and Soybean Boards (25 attendees). We have also presented at scientific conferences such as the National Sweetpotato Collaborators Group Annual Meeting and the Annual Southern Division American Phytopathological Society Meeting. UF: Results have been distributed through direct contact with growers and Extension Agents, publication of trade articles and Extension documents (in progress), presentations at regular extension events, and social media updates. Results were presented at Society of Nematology 2021 meeting in Alabama by Hung Bui (postdoc, Asian vegetables)), David Moreira (grad student, nematicide effects) and Gabrieli Riva (grad student, M.e. survey results). Updates on M.e. work was also given at grower's meetings (FL Ag expo, Strawberry grower's meeting, tomato grower's meeting and several county extension meetings). UGA: Outreach activities were done at multiple county grower meetings and Extension agent workshops in Georgia as well as at the Southeast Regional Fruit and Vegetable Conference (Savannah, GA) on the importance of M. enterolobii as a potential threat to agricultural crops. USDA-ARS: We disseminated information on the threat posed by M.e. and project results through two seminars presented to the departments of Plant Pathology at Louisiana State University and the University of Georgia, as well as through a virtual sweetpotato stakeholder symposium which had over 125 attendees. What do you plan to do during the next reporting period to accomplish the goals?NCSU: Quesada will generate publications to report findings of vegetable crops at risk of M. enterolobii infection and weeds that could serve as a green bridge for this nematode. Gorny will generate publications and extension deliverables of host resistance in sweetpotato to M. enterolobii. Quesada and Gorny will also continue field experiments to evaluate chemical control options for management of M. enterolobii. Quesada and Gorny will continue efforts to disseminate findings of this project to stakeholders. USDA-ARS: USDA-ARS: We will begin screening a core set of 384 genetically diverse sweetpotato clones for resistance to M.e. We will test additional advanced sweetpotato clones for resistance to M.e. We will confirm any M.e. resistance identified in the ongoing wild watermelon screens. We will begin developing biparental populations by crossing the M.e. tolerant pepper line, PMER-2, to susceptible pepper lines. Additional sweetpotato storage root samples will be collected and screened using our new survey method. CU:Continue to solicit samples from Horticulture and Agronomic agents throughout the Midlands and the Coastal Plain of SC will be solicited in person to submit nematode samples from cotton, soybean, sweetpotato and vegetable fields with a history of root-knot nematode problems. When possible, Dr. Mueller will personally visit the fields to collect samples and give one-on-one training to growers and consultants involved with the fields. If samples contain root-knot nematodes, females will be collected and speciated. If COVID 19 restrictions on travel and indoor group meetings are relaxed Dr. Mueller will give presentations at county and regional crop production meetings that include information on distribution and management of M. enterolobii. Otherwise, he will work to increase the number of within state Zoom meetings he participates in. UGA: Further investigation will consist of sampling from other counties and host crops throughout the state for potential detection of M. enterolobii.

Impacts
What was accomplished under these goals? We have increased our knowledge of incidence, distribution, and genetic variability of the invasive M.e. in the southeastern US. All states involved have engaged in systematic surveying and have identified M.e. in FL, SC, GA and NC. We identified sources of resistance for germplasm development. USDA has done extensive screening of accessions in cucurbit and solanaceous crops. Promising materials will be made available for breeders to incorporate into elite varieties. We evaluated non-host rotation options and other management tactics including the use of nematicides. NCSU and UF assessed the efficacy of nematicides, cover crops, and rotational crops. Findings will be critical to improve integrated pest management strategies. Objective 1. CU: Collected and speciated root-knot samples from 56 fields in South Carolina. Although many were not M. incognita, they also did not test positive for M. enterolobii. USDA: Confirmed the presence of M.e. in Charleston County South Carolina. UF: Anadditional 161 soil and root samples were collected in central and south FL from large medium and small commercial vegetable farms, community gardens and University research fields.More than 70% of samples contained root-knot nematodes. The most abundant RKN species were M. incognita, followed by M. enterolobii and M. javanica. In Asian vegetable farms, operated by Vietnamese growers, M. enterolobii was the most prevalent RKN species followed by M. incognita, M. arenaria and M. javanica. UGA: Between October 2019 to February 2022, a total of 23 crops from 222 fields across 39 counties of Georgia were sampled. Samples were submitted by University of Georgia Extension agents. Among the fields sampled, one field from Tattnal County and another field from Lowndes County were confirmed to be infested with Meloidogyne enterolobii. The crop grown in both these fields during sampling season was sweet potato. A more targeted survey was, subsequently, conducted in Tattnal and its neighboring counties (Bulloch and Evans). NCSU: Quesada completed evaluating the susceptibility of 18 hosts to a North Carolina population of M. enterolobii. Trials were performed in the greenhouse to determine the level of galling for these hosts and the eggs per gram of fresh root (ER) after 45 days. Two watermelon varieties, cabbage, pepper, one soybean variety, and tobacco were significantly infected with M. enterolobii. Broadleaf signalgrass, corn, one peanut variety, sudangrass, and nutsedge were less susceptible to M. enterolobii and considered poor hosts. A publication is being prepared to report these findings. Objective 2 USDA-ARS: We conducted M.e. resistance assays on germplasm from additional crop species, including wild watermelon relatives Citrullus ecirrhosus and C. amarus, and Irish potato cultivars. We generated mapping populations of the M.e. resistant pepper line PMER-2. We Identified quantitative trait loci (QTL) associated with M.e. resistance within the Citron melon (C. amarus) genome and submitted a manuscript for peer-review at the journal Plant Disease. Additional screening, genetic mapping, and breeding for M.e. resistance is ongoing in multiple vegetable species. Objective 3 NCSU: One trial was conducted in 2020 (Stancil's Chapell, NC) by Quesada and Gorny to evaluate chemical and host resistance control options for M. enterolobii in sweetpotato. The site was confirmed to be infested with M. enterolobii using molecular diagnostics prior to setting up field trials and nematode counts per plot were taken before, mid-way, and at the end of each trial. The site had variable nematode counts with the non-treated control showing very low nematode pressure. UF: Four common cover crops (sunn hemp, cowpea, sorghum-sudangrass and sunflower) were evaluated in the greenhouse for their host potential towards four root-knot species. M.e. did not reproduce on Sunn hemp and sorghum sudangrass but reproduced well on sunflower and cowpea. Efficacy of four chemical nematicides (oxamyl, fluensulfone, fluopyram, fluazaindolizine) and six biological nematicides) was evaluated in vitro (on M.e. juveniles) and in the greenhouse on cucumber inoculated with M.e. eggs. All chemical nematicides reduced M.e. activity in vitro and M e. infection on cucumber in the greenhouse. Biological nematicides showed no or minor effects. Velum, Vydate and Melocon are also being evaluated for the second year in three commercial pepper and two Asian vegetable (sweet potato and Thai basil) fields in Hillsborough County that are naturally infested with M.e.A 2021 sweetpotato small plot fumigation trial was discovered to be infested primary with M. enterolobii and so that data was folded into this project. In 2022, a broader range of nematicides are being evaluated for efficacy against M. enterolobii in a small plot sweetpotato field trial. Objective 4 UF: The US sweetpotato industry supply and price data model was used to quantify the US sweetpotato price responses to the supply shocks. The analysis shows the US sweet potato prices are highly sensitive to supply quantity and further highlight the importance and dominance of North Carolina sweet potatoes to the US market. The result suggests preventing supply disruptions like an outbreak of M.e. in North Carolina will affect not only the production and market supply of sweetpotatoes but also the market prices. Objecitive 5 CU/USDA: Dr. Rutter and Dr. Mueller initiated contact with the SCETV show "Making it Grow" and arranged for the design and production of an 'In field" video on detecting and managing M. e. in vegetable fields and gardens. Dr. Rutter was the featured speaker. The video aired on October 11th, 2022. After the telecast it will be available for viewing in the SCETV archives. USDA: Dr. Rutter and Dr. Wadlproduced a video describing the threat posed by M.e. and the research our group is working on tomanage and mitigate the spread of this nematode in the field. A link to the YouTube video is now available on the FindMe website. NCSU:Quesada provided diagnostics and disease management recommendations for 97 vegetable crop samples submitted in 2020 to the NC State Plant Disease and Insect Clinic. Quesada has also been involved in providing disease management recommendations through oral presentations, social media (Twitter: 4,010 (lab) + 2,258 (Quesada) followers, LinkedIn: 2,406 followers). Gorny has been involved with providing nematode biology and management information through direct recommendations to growers and agents, and oral presentations. Quesada and Gorny have presented results as oral talks or posters at scientific conferences such as the Annual Southern Division American Phytopathological Society Meeting, American Phytopathological Society Annual Meeting, and the Society of Nematologists Annual Meeting. Gorny was involved with and provided content for agent training in biology and management of nematodes in vegetable production. CU: We increased project awareness through the creation of a project content and dissemination through outlets such as twitter (https://twitter.com/FINDMeNematode), our YouTube channel and website (https://www.findmenematode.org/). Our followers on twitter have increased by 60%. This is largely due to the release of content such as informational videos and helpful materials creating awareness. We have also seen an almost 300% percent increase in twitter impressions. Our website visits have also increased by 25%. The project released a video detailing sampling and diagnosis of m.e. FINDMe has also had a large presence at producer field days, industry expos, and scientific meetings. UF: Results have been distributed through direct contact with growers and Extension Agents, publication of trade articles and extension documents, presentations at regular extension events, and social media updates.

Publications

• Type: Conference Papers and Presentations Status: Under Review Year Published: 2022 Citation: Soto-Caro, A., Luo, T, Wu, F., Guan, Z. 2022 Southern Agricultural Economics Association Annual Meeting Selected Paper Conference Paper-Under Review
• Type: Conference Papers and Presentations Status: Awaiting Publication Year Published: 2022 Citation: Parada-Rojas C. H. and Quesada-Ocampo L. M. Revealing the NLRome of cultivated hexaploid sweetpotato. Phytopathology: in press.
• Type: Journal Articles Status: Under Review Year Published: 2022 Citation: Collins H., Adams M. L., Quesada-Ocampo L.M. (2022) Evaluation of nematicides for control of Southern and Guava Root Knot Nematode in sweetpotato, 2019. Plant Disease Management Reports: submitted.
• Type: Other Status: Published Year Published: 2022 Citation: Southeastern Vegetable Extension Workers. Kemble J., Meadows I., Jennings K. M., and Walgenbach J. F., Eds. (2022) Southeastern US 2022 Vegetable Crop Handbook. Basil, cucurbits, hop, lettuce, endive, sweetpotato, and fungicide resistance tables (Quesada Contributed 11 tables total).
• Type: Other Status: Published Year Published: 2021 Citation: Quesada-Ocampo L. M., Meadows I., and Gorny A. (2021) Disease control for commercial vegetables. North Carolina Agricultural and Chemicals Manual. Basil, cucurbits, hop, lettuce, endive, sweetpotato, and fungicide resistance tables (Quesada Contributed 11 tables total).
• Type: Other Status: Published Year Published: 2021 Citation: Quesada-Ocampo L. M. (2017, updated in 2020 and 2021) Sweetpotato root knot nematode. Vegetable Pathology Factsheets. NC State Extension Publications. URL: https://content.ces.ncsu.edu/sweetpotato-root-knot-nematode
• Type: Other Status: Published Year Published: 2021 Citation: Schwarz, T. and Gorny, A. 2020. Root-Knot Nematode of Tomato. NC State Extension Publication. URL: https://content.ces.ncsu.edu/root-knot-nematode-of-tomato
• Type: Other Status: Published Year Published: 2021 Citation: Mueller, J., and Corbin, J. 2021. Meloidogyne enterolobii (M.e.) and the Challenge for Home Gardeners. Clemson Home Garden and Information Center Blog. July 29, 2021.
• Type: Websites Status: Published Year Published: 2021 Citation: Website: https://www.findmenematode.org/
• Type: Other Status: Published Year Published: 2021 Citation: Day, J., Mueller, J., Desaeger, J., Gorny, A.M., and Agudelo, P. The latest nematode invasion in the southeast US: How commercial farms and home gardeners can prevent the spread of M.e. May 2021. https://www.findmenematode.org/project-updates/the-latest-nematode-invasion-in-the-southeast-us https://www.morningagclips.com/how-you-can-help-stop-a-plant-pest/
• Type: Conference Papers and Presentations Status: Published Year Published: 2021 Citation: Agudelo, Paula, J. Corbin, J. Desaeger, A. Gorny, Z. Grabau4, Z. Guan, A. Hajihassani, J. Mueller, L. Quesada, W. Rutter, and P. Wadl. A Multi-State Effort to Contain and Manage Meloidogyne Enterolobii in Vegetable Crops. SOciety of Nematology Poster Abstract Submitted June 2021.
• Type: Other Status: Published Year Published: 2021 Citation: Grabau Z. J. and Liu C. (2020) What Florida growers need to know about the invasive guava root-knot nematode. Panhandle Ag e-News. URL: https://nwdistrict.ifas.ufl.edu/phag/2020/10/30/what-florida-growers-need-to-know-about-the-invasive-guava-root-knot-nematode/
• Type: Conference Papers and Presentations Status: Published Year Published: 2021 Citation: Grabau Z. J. and Sandoval-Ruiz R. Fumigation chemistries and methods for Meloidogyne incognita management in sweetpotato. Society of Nematologists annual meeting, Gulf Shores, AL, September 2021. Oral Presentation.
• Type: Conference Papers and Presentations Status: Published Year Published: 2021 Citation: Liu C. and Grabau Z. J. Nematode management in Florida sweet potato using non-fumigant nematicides. Society of Nematologists annual meeting, Gulf Shores, AL, September 2021. Poster Presentation.
• Type: Conference Papers and Presentations Status: Published Year Published: 2021 Citation: Grabau Z. J. Nematode management in ethnic vegetables. Ethnic vegetable field day, University of Florida Plant Science Research and Education Unit, Citra, FL, July 2021. Oral Presentation.

Progress 09/01/20 to 08/31/21

Outputs
Target Audience:The target audiences reached by our efforts during thisreporting period were farmers, breeders, germplasm curators, extension specialists and agents, university collaborators, USDA collaborators, and our advisory board. Changes/Problems:Progress in some objectives has been delayed due to coronavirus-related restrictions but we are making good progress towards objective completion, and we do not expect any issues in performing project activities as proposed. Survey efforts, training programs and grower awareness meetings have been curtailed by travel and meeting restrictions. What opportunities for training and professional development has the project provided?Multiple Extension meetings, Field Days, and workshops throughput North Carolina, South Carolina, Georgia, and Florida. NCSU: Faculty, technicians, postdocs, graduate students, and undergraduate students have received training in nematode biology and management through this project. Some personnel in our groups that are not directly supported by the project have also benefited and learned from the activities performed in our programs. Early-career scientists from underrepresented backgrounds have been effectively engaged in the project. USDA-ARS: A post-doc (Dr. Benjamin Waldo) was hired to perform the M. e. screening experiments at the USVL and had the opportunity to begin screening watermelon and sweetpotato. A master's student (Julianna Culbreath) helped to set up the screening experiments for both pepper and sweetpotato, and is working to develop the new storage root survey method for M.e. Clemson: One-on-one training sessions were held with Zack Snipes (Charleston area Hort. agent), Justin Ballew (Lexington Commercial Hort. Agent), Rob Last (Savannah Valley Hort. agent), and Phillip Carnley (Orangeburg Area Commercial Hort. Agent). Did one-on-one in-field trainings with Agronomic row crop agents Jonathan Croft (Orangeburg & Dorchester Counties), Jay Crouch (Newberry & Saluda Counties), Steven Crowder (Allendale & Hampton Counties), and Hannah Mikel (Clarendon & Sumter Counties), One-on-one training sessions in-the-field were held with Crop Consultants Jerry Adams (Lee County area) and Fleming McMaster (Upper Savannah Valley area). UF: The bioscientist on this project learned to identify root-knot nematode species using PCR-based molecular techniques. Gaining experience with molecular techniques is something they identified as an important part of their professional training. Student training and postdoc professional development was also provided. New MS student was trained in molecular id of M.e. UGA: A MSc student (Gema Nugraha) and a Postdoc (Banani Mondal) were hired to work on molecular detection of root-knot nematodes. How have the results been disseminated to communities of interest?Scientific Meetings, Extension publications, Extension meetings and events, Web-based materials. NCSU: We have presented results from this project to stakeholders at several extension venues such as the annual North Carolina Sweetpotato field day, the Organic Commodities and Livestock Conference, field days, and regional crop production meetings. We have also presented at scientific conferences such as the Annual Southern Division American Phytopathological Society Meeting, the American Phytopathological Society Annual Meeting, and the Society of Nematologists Annual Meeting. Clemson: Survey results and the damage potential of M.e. were presented to growers, agents, and industry personnel at the S.C. State Cotton meeting (125+ attendees), the Savannah Valley Cotton Production Meeting (75 attendees), Edisto REC Fall Field Day (50 attendees), the 2019 Certified Crop Advisors training meeting (30 attendees) and to meetings of the S.C. Cotton and Soybean Boards (25 attendees). We have also presented at scientific conferences such as the National Sweetpotato Collaborators Group Annual Meeting and the Annual Southern Division American Phytopathological Society Meeting. UF: Results have been distributed through direct contact with growers and Extension Agents, publication of trade articles and Extension documents (in progress), presentations at regular extension events, and social media updates. Results were presented at Society of Nematology 2021 meeting in Alabama by Hung Bui (postdoc, Asian vegetables)), David Moreira (grad student, nematicide effects) and Gabrieli Riva (grad student, M.e. survey results). Updates on M.e. work was also given at grower's meetings (FL Ag expo, Strawberry grower's meeting, tomato grower's meeting and several county extension meetings). UGA: Outreach activities were done at multiple county grower meetings and Extension agent workshops in Georgia as well as at the Southeast Regional Fruit and Vegetable Conference (Savannah, GA) on the importance of M. enterolobii as a potential threat to agricultural crops. USDA-ARS: We disseminated information on the threat posed by M.e. and project results through two seminars presented to the departments of Plant Pathology at Louisiana State University and the University of Georgia, as well as through a virtual sweetpotato stakeholder symposium which had over 125 attendees. Examples: Production Guides 1. Southeastern Vegetable Extension Workers. Kemble J., Meadows I., Jennings K. M., and Walgenbach J. F., Eds. (2022) Southeastern US 2022 Vegetable Crop Handbook. Basil, cucurbits, hop, lettuce, endive, sweetpotato, and fungicide resistance tables (Quesada Contributed 11 tables total). 2. Quesada-Ocampo L. M., Meadows I., and Gorny A. (2022) Disease control for commercial vegetables. North Carolina Agricultural and Chemicals Manual. Basil, cucurbits, hop, lettuce, endive, sweetpotato, and fungicide resistance tables (Quesada Contributed 11 tables total). 3. Southeastern Vegetable Extension Workers. Kemble J., Meadows I., Jennings K. M., and Walgenbach J. F., Eds. (2021) Southeastern US 2021 Vegetable Crop Handbook. Basil, cucurbits, hop, lettuce, endive, sweetpotato, and fungicide resistance tables (Quesada Contributed 11 tables total). Extension Fact Sheets 1. Quesada-Ocampo L. M. (2017, updated in 2020 and 2021) Sweetpotato root knot nematode. Vegetable Pathology Factsheets. NC State Extension Publications. URL: https://content.ces.ncsu.edu/sweetpotato-root-knot-nematode 2. Schwarz, T. and Gorny, A. 2020. Root-Knot Nematode of Tomato. NC State Extension Publication. URL: https://content.ces.ncsu.edu/root-knot-nematode-of-tomato 3. Agudelo, P. and Day, J. 2020. Factsheets for management of M. enterolobiii, for commercial growers and for homeowners.The latest nematode invasion in the southeast US -- FINDMe (findmenematode.org) Extension websites for stakeholder training 1. Extension Plant Pathology Portal: http://plantpathology.ces.ncsu.edu/. 2. Vegetable Pathology lab website: http://go.ncsu.edu/veggiepathology/. 3. Grabau Z. J. and Liu C. (2020) What Florida growers need to know about the invasive guava root-knot nematode. Panhandle Ag e-News. URL: https://nwdistrict.ifas.ufl.edu/phag/2020/10/30/what-florida-growers-need-to-know-about-the-invasive-guava-root-knot-nematode/ What do you plan to do during the next reporting period to accomplish the goals?We will continue sampling efforts and will intensify greenhouse and field evaluations. We will analyze datafrom previously completed experiments and will continue to refine the economic models. New educational materials will be produced. NCSU: Quesada will generate publications to report findings of vegetable crops at risk of M. enterolobii infection and weeds that could serve as a green bridge for this nematode. Gorny will generate publications and extension deliverables of host resistance in sweetpotato to M. enterolobii. Quesada and Gorny will also continue field experiments to evaluate chemical control options for management of M. enterolobii. Quesada and Gorny will continue efforts to disseminate findings of this project to stakeholders. USDA-ARS: USDA-ARS: We will begin screening a core set of 384 genetically diverse sweetpotato clones for resistance to M.e. We will test additional advanced sweetpotato clones for resistance to M.e. We will confirm any M.e. resistance identified in the ongoing wild watermelon screens. We will begin developing biparental populations by crossing the M.e. tolerant pepper line, PMER-2, to susceptible pepper lines. Additional sweetpotato storage root samples will be collected and screened using our new survey method. Clemson:Continue to solicit samples from Horticulture and Agronomic agents throughout the Midlands and the Coastal Plain of SC will be solicited in person to submit nematode samples from cotton, soybean, sweetpotato and vegetable fields with a history of root-knot nematode problems. When possible, Dr. Mueller will personally visit the fields to collect samples and give one-on-one training to growers and consultants involved with the fields. If samples contain root-knot nematodes, females will be collected and speciated. If COVID 19 restrictions on travel and indoor group meetings are relaxed, Dr. Mueller will give presentations at county and regional crop production meetings that include information on distribution and management of M. enterolobii. Otherwise, he will work to increase the number of within state Zoom meetings he participates in.

Impacts
What was accomplished under these goals? IMPACT.We have increased our knowledge of incidence, distribution, and genetic variability of the invasive M.e. in the southeastern US.We identified sources of resistance for germplasm development. Promising materials will be made available for breeders to incorporate into elite varieties.We evaluated non-host rotation options and other management tactics including the use of nematicides. NCSU and UF assessed the efficacy of nematicides, cover crops, and rotational crops. Findings will be critical to improve integrated pest management strategies. Objective 1. CU: We collectedsamples for 93 vegetable and 67 row crops. Many did not testas M. incognita;none of them wereM. enterolobii. These samples came from Bamberg, Barnwell, Charleston, Clarendon, Colleton, Hampton, Lexington, Newberry, Saluda, and Sumter counties. USDA: We developed a method for testing batches of sweetpotato. Fifteen batches were tested using our new survey methodology, including 8 samples collected from grocery stores and grower fields in South Carolina. We have detected and/or recovered live root-knot nematodes from 5 of these sweetpotato samples, and are in the process of confirming our species identification. UF: Total of 223 root or soil samples were collectedfrom commercial agronomic and row crops in North Florida. Of samples collected, Meloidogyne spp. were detected in 100 samples. Molecular identification revealed M. incognita (15), M. arenaria (8), M. javanica (1), and M. enterolobii (9). UGA: 187 soil samples were received fromcotton, peanut, tobacco, and several vegetable crops in 35 counties. Most fields were infested with only Meloidogyne incognita (82%) followed by a mixed population of M. incognita and M. arenaria (9%); M. arenaria (5%); M. javanica (1%); M. incognita and M. javanica (1%); M. arenaria and M. javanica (1%), and a mixed population of the three species (1%). Objective 2. NCSU: Quesada evaluated the susceptibility of 18 hosts to a North Carolina population ofM. enterolobii.Trials were performed in the greenhouse to determine the level of galling and the eggs per gram of fresh root (ER) after 45 days. Hosts evaluated included cucumber 'Arabian', watermelon 'Fascination' and 'Charleston gray', cabbage 'Stonehead', pepper 'Red Bull', hemp 'Felina', peanut 'Sulivan' and 'Tifguard', corn 'Early sunglow', tobacco 'K326', cotton 'Deltapine 1646', soybean '7310RY' and 'P5018RX', winter wheat 'Kaskia', sudangrass 'Piper', and the weeds palmer amaranth, yellow nutsedge, and broadleaf signalgrass. Two watermelon varieties, cabbage, pepper, one soybean variety, and tobacco were significantly infected withM. enterolobii. Broadleaf signalgrass, corn, one peanut variety, sudangrass, and nutsedge were less susceptible toM. enterolobiiand considered poor hosts. Gorny began evaluating the durability of resistance in sweetpotato by screening diverse sweetpotato genotypes against two distinct populations ofM. enterolobiifrom North Carolina. In the greenhouse, replicate trials are ongoing to determine the severity of root galling and eggs per gram of fresh root for nine sweetpotato genotypes ('Beauregard', 'Covington', 'Centennial', 'Jewel', 'Murasaki-29', 'Tanzania', 'Dimbuka-Bukulula', 'Bwanjule', and Tib-11 [genotype from an experimental cross]). Of these, 'Murasaki-29', 'Tanzania', 'Dimbuka-Bukulula', 'Bwanjule', and Tib-11, were determined to be resistant in prior experiments, but durability of the resistance was unknown. USDA-ARS:Sixty-nine first year seedlings were selected from breeding nurseries that had M.e. resistant parents. Two advanced breeding sweetpotato clones were confirmed to be resistant to M.e. and intermediately resistant to other soil dwelling pests. The newly identified clones will be used in sweetpotato breeding nurseries in FY22. An M.e. tolerant pepper line was selected, PMER-2, which displayed less galling and nematode egg production compared to susceptible control lines and produced a 70% larger root system under infected conditions. Crosses have been initiated in the greenhouse to determine if this resistance trait will be useful for breeding new resistant pepper varieties. Screens are underway to evaluate the susceptibility of 126 diverse wild watermelon lines to M.e. Objective 3. NCSU: One trial was conducted in 2020 to evaluate chemical and host resistance control options for M. enterolobii in sweetpotato. The site had variable nematode counts with the non-treated control showing very low nematode pressure. Two trials were established in 2021 to evaluate chemical control options for M. enterolobii in sweetpotato. Both sites were confirmed to be infested with the nematode. UF: We analyzed the 2019 and 2020 tomatoes' yield data provided by UF GCREC Dr. Desaeger's team to evaluate the economic feasibilities of different nematode treatments. Preliminary results show that the most widely adopted treatment, fumigation, may not be the most economically profitable option for the Florida tomato growers. Efficacy of four chemical nematicides (oxamyl, fluensulfone, fluopyram, fluazaindolizine) and six biological nematicides) was evaluated in vitro (on M.e. juveniles) and in the greenhouse on cucumber inoculated with M.e. eggs. All chemical nematicides reduced M.e. activity in vitro and M. e. infection on cucumber in the greenhouse. Biological nematicides showed no or minor effects. Velum, Vydate and Melocon are also being evaluated in a commercial pepper and Asian vegetable field naturally infested with M.e. Four common cover crops (sunn hemp, cowpea, sorghum-sudangrass and sunflower) were evaluated in the greenhouse for their host potential towards four root-knot species. M.e. did not reproduce on Sunn hemp and sorghum sudan, but reproduced well on sunflower and cowpea. Objective 4. UF: The US sweetpotato industry supply and price data model was used to quantify the US sweetpotato price responses to the supply shocks. The analysis shows the US sweet potato prices are highly sensitive to supply quantity and further highlight the importance and dominance of North Carolina sweet potatoes to the US market. The result suggests preventing supply disruptions like an outbreak of M.e. in North Carolina will affect not only the production and market supply of sweetpotatoes but also the market prices. ?Objective 5. USDA: Dr. Rutter and Dr. Wadlproduced a videodescribing the threat posed by M.e. and the research our group is working on to manage and mitigate the spread of this nematode in the field. NCSU:Quesada provided diagnostics and disease management recommendations for 97 vegetable crop samples submitted in 2020 to the NC State Plant Disease and Insect Clinic. Gorny has been involved with providing nematode biology and management information through direct recommendations to growers and agents, and oral presentations. Quesada and Gorny have generated disease management publications such as the NC Agricultural and Chemicals Manual and the Southeastern US Vegetable Crop Handbook. Gorny has created three extension videos from project initiation to date onM. enterolobiiin sweetpotato. Clemson: We increased project awareness through popular press and new materials on website (https://www.findmenematode.org/) and social media (https://twitter.com/FINDMeNematode). The team developed blogs and factsheetsforhomeownersand commercial growers to increase awareness ofM.e. The factsheetswere translated into Vietnamese and Spanish. All investigators have presented results as oral talks or posters at scientific conferences such as the Annual Southern Division American Phytopathological Society Meeting, American Phytopathological Society Annual Meeting, and the Society of Nematologists Annual Meeting.

Publications

• Type: Book Chapters Status: Published Year Published: 2021 Citation: Parada-Rojas C. H., Quesada-Ocampo L. M. (2021) Uncovering the NLR family of disease resistance genes in cultivated sweetpotato and wild relatives. Chapter 3. In: Postharvest Pathology: Next Generation Solutions to Reducing Losses and Enhancing Safety. Editors: Spadaro D., Droby S., and Gullino M.L. Springer.
• Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Rutter, W. B., Wadl, P. A., Mueller, J. D. and P. Agudelo. 2020. Identification of Sweetpotato Germplasm Resistant to Pathotypically Distinct Isolates of Meloidogyne enterolobii from the Carolinas. Plant Disease (in press)
• Type: Conference Papers and Presentations Status: Awaiting Publication Year Published: 2021 Citation: Parada-Rojas C. H. and Quesada-Ocampo L. M. Revealing the NLRome of cultivated hexaploid sweetpotato. Phytopathology: in press.
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Wong T. S. and Quesada-Ocampo L. M. (2020) Evaluation of SDHIs for control of southern root-knot nematode and fungal pathogens in watermelon. Phytopathology 110: S1.20.
• Type: Conference Papers and Presentations Status: Published Year Published: 2020 Citation: Ye W, Schwarz T., Davis E. L., Thiessen L. D., Quesada-Ocampo, L. M., and Gorny A. M. (2020) Occurence of the root-knot nematode Meloidogyne enterolobii infecting sweetpotato in North Carolina, United States. Phytopathology 110: S1.2.
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Philbrick, A., Adhikari, T. B., Louws, F. J., and Gorny, A. M. 2020 . Meloidogyne enterolobii, a major threat to tomato production: Current status and future prospects for its management. Frontiers in Plant Science. 11:article 606395 DOI:10.3389/fpls.2020.606395
• Type: Journal Articles Status: Awaiting Publication Year Published: 2021 Citation: Collins H., Adams M. L., Quesada-Ocampo L.M. (2021) Evaluation of nematicides for control of Southern and Guava Root Knot Nematode in sweetpotato, 2019. Plant Disease Management Reports: in press.
• Type: Journal Articles Status: Submitted Year Published: 2021 Citation: Collins H., Adams M. L., Quesada-Ocampo L.M. (2021) Evaluation of nematicides for control of Southern and Guava Root Knot Nematode in sweetpotato, 2019. Plant Disease Management Reports: submitted.
• Type: Journal Articles Status: Published Year Published: 2021 Citation: Sandoval-Ruiz R., Jones M. A. and Grabau Z. J. (2021) Efficacy of fumigant nematicides for managing southern root-knot nematode in Florida cucumber, 2020. Plant Disease Management Reports 15:N047
• Type: Journal Articles Status: Published Year Published: 2021 Citation: Liu C., Jones M. A., and Grabau Z. G. (2021) Impact of nematicide application on root-knot nematode management in Florida fall watermelon, 2019. Plant Disease Management Reports 15:N50.
• Type: Journal Articles Status: Published Year Published: 2021 Citation: Wolday Tsegay M., Jones M. A., and Grabau Z. G. (2021) Root-knot nematode management by nematicide application in Florida watermelon, 2020. Plant Disease Management Reports 15:N51.

Progress 09/01/19 to 08/31/20

Outputs
Target Audience:The target audiences reached by our efforts during thie reporting period werefarmers, breeders, germplasm curators, extension specialists andagents,university collaborators,USDA collaborators, and our advisory board. Changes/Problems:CHANGES OR PROBLEMS North Carolina State University: Progress in some objectives has been delayed due to coronavirus-related restrictions but we are making good progress towards objective completion and we do not expect any issues in performing project activities as proposed. USDA-ARS: The USVL and USDA-ARS as a whole was shut down due to the COVID 19 pandemic on March 31st, 2020. This has been a serious setback for the project and the completion of all milestones and goals at the USVL has been delayed for the past 6 months. Clemson University: Survey efforts, training programs and grower awareness meetings have been severely curtailed by travel and meeting restrictions due to COVID 19. University of Florida: UF shutdown due to COVID 19 delayed progress with this project. Sweetpotato acreage was projected to be down this year in Florida, so we will likely shift some planned sweetpotato samples to other crops such as Irish potatoes.? What opportunities for training and professional development has the project provided?NCSU: Faculty, technicians, postdocs, graduate students, and undergraduate students have received training in nematode biology and management through this project. Some personnel in our groups that are not directly supported by the project have also benefited and learned from the activities performed in our programs. Early-career scientists from underrepresented backgrounds have been effectively engaged in the project. USDA-ARS: A post-doc (Dr. Lesley Schumacher) was hired to perform the M. e. screening experiments at the USVL and had the opportunity to help select germplasm for future screening before she received a permanent appointment at another USDA-ARS Unit in August. A master's student (Julianna Culbreath) helped to set up the screening experiments for both pepper and sweetpotato. CU: A field day was held at the Orangeburg County Test site with 12 growers, consultants, and agents attending. One-on-one visits were made with a total of 20 growers and agents in Aiken, Bamberg, Barnwell, Calhoun, Newberry, and Orangeburg Counties. Agudelo conducted the Plant Parasitic Nematode Identification course in December of 2019 with 23 participants from across the country. UF: The bioscientist on this project learned to identify root-knot nematode species using PCR-based molecular techniques. Gaining experience with molecular techniques is something they identified as an important part of their professional training. Student training and postdoc professional development was also provided. UGA: A Postdoctoral Associate (Dr. Fereidoun Forghani) was able to assist in molecular detection of root-knot nematodes How have the results been disseminated to communities of interest?NCSU: We have presented results from this project to stakeholders at several extension venues such as the annual NC Sweetpotato field day, the NC Vegetable Growers Association Ag Expo, and the greenhouse vegetable production agent training. We have also presented at scientific conferences such as the National Sweetpotato Collaborators Group Annual Meeting, the Annual Southern Division American Phytopathological Society Meeting, and the American Phytopathological Society Annual Meeting. Quesada provided diagnostics and disease management recommendations for 95 in 2019 and 60 in 2020 vegetable crop samples submitted to the NC State Plant Disease and Insect Clinic. Quesada has also been involved in providing disease management recommendations through oral presentations, social media (Twitter: 2,962 (lab) + 1,369 (Quesada) followers, Facebook: 847 followers, LinkedIn: 2,176 followers). Quesada was also involved in an agent training about diagnostics and control of vegetable diseases in greenhouse production. Quesada, Thiessen, and Gorny have presented results as oral talks or posters at scientific conferences such as the National Sweetpotato Collaborators Group Annual Meeting, the Annual Southern Division American Phytopathological Society Meeting, and the American Phytopathological Society Annual Meeting. Gorny was involved with and provided content for agent training in biology and management of nematodes in vegetable production. Thiessen was also involved in providing content for agent and stakeholder trainings for rotational crop nematode management. Quesada has generated disease management publications such as the NC Agricultural and Chemicals Manual, the Southeastern US Vegetable Crop Handbook, and the Sweetpotato root knot nematode fact sheet. Quesada supported three demonstration field experiments in 2019 and one in 2020 to train growers and agents in the use of chemical control and tolerant varieties for management of M. e.. Quesada has presented results from this project to stakeholders at several extension venues such as the annual NC Sweetpotato field day, the NC Vegetable Growers Association Ag Expo, and the greenhouse vegetable production agent training. Gorny has contributed to relevant sections of the NC Agricultural and Chemicals Manual and the Southeastern US Vegetable Crop Handbook. Gorny has presented results and instruction in nematode management to stakeholders at extension venues including the NC Sweetpotato field day, Organic Commodities and Livestock Conference, and regional production meetings. Gorny has created two extension videos on M. e. in sweetpotato that have been posted to the NC State Extension website and YouTube channel. Thiessen has generated disease management publication materials including the NC Agricultural and Chemical Manual, NC Cotton Production Guide, NC Soybean Production Guide, the cotton root knot nematode fact sheet, and the soybean root knot nematode fact sheet. Thiessen has also presented results from this project to stakeholders at county extension meetings in January and February of 2020 to train stakeholders on chemical and management of rotational crops. CU: Survey results and the damage potential of M.e. were presented to growers, agents, and industry personnel at the S.C. State Cotton meeting (125+ attendees), the Savannah Valley Cotton Production Meeting (75 attendees), Edisto REC Fall Field Day (50 attendees), the 2019 Certified Crop Advisors training meeting (30 attendees) and to meetings of the S.C. Cotton and Soybean Boards (25 attendees). We have also presented at scientific conferences such as the National Sweetpotato Collaborators Group Annual Meeting and the Annual Southern Division American Phytopathological Society Meeting. UF: Most outreach has occurred with extension agents by direct contact or participating in regular agriculture update weeks. UGA: The results of the project have not yet been communicated with growers and the agricultural community. However, outreach activities have been done at multiple county grower meetings in GA and at the Southeast Regional Fruit and Vegetable Conference (Savannah, GA) on the importance of Meloidogyne e. as a potential threat to agricultural crops. What do you plan to do during the next reporting period to accomplish the goals?NCSU: Quesada will continue greenhouse experiments to determine vegetable crops at risk of M.e. infection and weeds that could serve as a green bridge for this nematode. Quesada, in collaboration with Gorny, will also continue field experiments to evaluate chemical control options for management of M.e. Thiessen will continue with rotational crop experiments. Quesada, Gorny, and Thiessen will continue efforts to disseminate findings of this project to stakeholders. USDA-ARS: Another post-doc will be hired to perform the M.e. screening experiments at the USVL. Split-root screening experiments will be used to continue the evaluation of the putatively resistant pepper lines until at least one line with true-breeding resistance is generated. Selected cucurbit germplasm will be obtained from GRIN and high throughput screens for resistance will be initiated. CU: County agents in the Coastal Plain of SC will be solicited in person to submit nematode samples from cotton, soybean, sweetpotato and vegetable fields with a history of root-knot nematode problems. Drs. Mueller and Ahmed will conduct in-person surveys of sweetpotato production fields in Bamberg, Darlington, Florence and Orangeburg Counties. Between the two efforts 75 to 100 samples from problem fields should be processed. Nematodes will be extracted and speciation will be performed at the newly created Edisto Nematode Laboratory at the Edisto REC. Regarding objective 5, efforts to educate and disseminate knowledge to target audiences will be increased via web and print resources. UF: We will analyze data from the experimental trials in NC and other states to identify cost-effective treatments in controlling M.e. We will also propose a supply and demand model to evaluate the potential impact of M.e. on the specialty crop industry. We plan to continue surveying for M.e. In particular, we are looking for suitable M.e.-positive sites to conduct field trials on M.e. management. We will also set up a greenhouse nematicide trial with M.e., and evaluate cover crops for host status. UGA: Soil and root samples will be obtained from other counties in the state and processed for potential detection of M.e.

Impacts
What was accomplished under these goals? We have increased our knowledge of incidence, distribution, and genetic variability of the invasive M.e. in the southeastern US. All states involved have engaged in systematic surveying of symptomatic crops and have identified M.e. in 3 states - FL, SC, and NC. These results help inform state-level quarantine measures.We identified sources of resistance for germplasm development. USDA has done extensive screening of accessions in cucurbit and solanaceous crops. Promising materials will be made available for breeders to incorporate into elite varieties.We also evaluated non-host rotation options and other management tactics including the use of nematicides. NCSU and UF assessed the efficacy of nematicides, cover crops, and rotational crops. Findings will be critical to improve integrated pest management strategies. Obj 1. Study the prevalence and distribution of M.e. and characterize the genetic variability CU: Fifty-six cotton and peanut fields sampled in Bamberg Co. were positive for M. incognita. A second survey in Orangeburg Co. with very high reproduction and galling on SRK resistant soybean varieties tested negative for M.e. and positive for M. incognita. In a third project 14 soybean fields with a history of severe galling and plant mortality, two populations were tested and both came back as M. arenaria. Plots comparing SRK resistant and susceptible soybean cultivars have been established in fields with a history of root-knot problems in Marion and Orangeburg Co. and two fields in Florence Co. Clemson hired a postdoc to process samples and start greenhouse trials. UF: Until we identify suitable field sites to conduct M.e.-specific management trials, we continue to work with other root-knot nematode species which provide preliminary data about tactics that may work for M.e. Samples were collected from 4 counties in central FL from 22 farms comprising 25 different plant species. A total of 122 female individuals were identified to species level. M.e. was found on 6 farms in 14 plant species (basil, garden egg, luffa, malaba spinach, perila, pumpkin, sweet potato, jude plant, bean, hot pepper, squash, eggplant, okra, red beet). Other root-knot nematode species found were M. incognita, M. arenaria. M. javanica, M. hapla and M. haplanaria. UGA: A total of 158 soil and/or root samples were obtained from 31 counties via submissions by UGA extension personnel. Samples were obtained from fields with symptomatic damage. Crops included cotton, peanut, corn, soybean, tobacco, sorghum, lima bean, snap bean, green bean, butter bean, cabbage, collards, cantaloupe, carrot, cucumber, okra, potato, squash, sweet potato, tomato, watermelon and pepper. Root-knot nematodes were present in 128 samples (incidence 81%), with the population density ranging from 1 to 1,640 nematodes per 100 cm3 of soil. M.e. has not been found in GA. NCSU: Susceptibility of 18 hosts to M.e. was evaluated in cucumber 'Arabian', watermelon 'Fascination' and 'Charleston gray', cabbage 'Stonehead', pepper 'Red Bull', hemp 'Felina', peanut 'Sulivan' and 'Tifguard', corn 'Early sunglow', tobacco 'K326', cotton 'Deltapine 1646', soybean '7310RY' and 'P5018RX', winter wheat 'Kaskia', sudangrass 'Piper', and the weeds palmer amaranth, yellow nutsedge, and broadleaf signalgrass. M.e. was able to reproduce on all plants. Two watermelon varieties, cabbage, pepper, one soybean variety, and tobacco were significantly infected with M.e. Broadleaf signalgrass, corn, one peanut variety, sudangrass, and nutsedge were less susceptible to M.e. and considered poor hosts. Gorny screened 9sweetpotato genotypes against two populationsfrom NC: 'Beauregard', 'Covington', 'Centennial', 'Jewel', 'Murasaki-29', 'Tanzania', 'Dimbuka-Bukulula', 'Bwanjule', and Tib-11. Obj 2. Evaluate and develop vegetable germplasm with resistance against M.e. USDA-ARS: Eighty-six wild pepper Plant Introduction (PI) lines were screened for resistance to M.e. No line showed resistance across all 4 replicates, but 7 individual plants showed little to no infection. The stems of these plants were propagated for seed, and inoculated split-root experiments have been initiated to confirm this resistance and generate true-breeding lines that will provide breeding material. Additionally, 384 sweetpotato PIs were selected based on available genotype and phenotype data for screening with M.e. and eventual GWAS analysis. An experiment was initiated to quantify the effect of M. e. resistance on the development of sweetpotato storage roots. Obj 3. Evaluate the efficacy of rotations, cover crops, and nematicides NCSU: Three trials were conducted in 2019 (Meadow, Bailey, and Pinceton) and one in 2020 (Stancil's Chapell) to evaluate chemical and host resistance control options. The sites in Bailey and Princeton had variable nematode counts with the non-treated control showing low nematode pressure. Meadow had more uniform nematode pressure and showed significant control of M.e. by Telone II + Velum Prime (current recommendation) and K-PAM. In addition, varieties 'Murasaki 29' and 'Jewel' showed lower nematode damage than 'Covington'. Rotational crop trials were established in Johnston Co. following sweetpotato evaluating two cultivars of soybean (RKN susceptible and resistant) and cotton (RKN susceptible and resistant). Treatments (Propulse foliar broadcast, Velum in furrow, and Velum + Propulse) were applied to each plot and are currently being evaluated. UF: An invitro assay wasconducted evaluating the efficacy of different nematicides (oxamyl, fluensulfone, fluopyram, fluazaindolizine and Burkholderia toxins) on M.e. juveniles. Obj 4. Assess the costs and returns of management tactics UF: A spatial risk analysis across FL has been conducted to evaluate the vulnerability to economic loss due to M.e. Each county is analyzed based on its crop mix to measure its vulnerability to nematode outbreak or establishment. We also analyzed major crops across FL, GA, SC, and NC which will provide macro-level information for nematode management in these states. The results emphasize the importance of interstate cooperation to control and eliminate the impact of M.e. FL is at great risk of large economic losses if M.e. is established because manymainspecialty crops are susceptible. The counties that are more vulnerable are in Northwest and Southeast regions. Obj 5. Develop print and web-based materials A project manager was hired in October 2019 and has led team efforts to accomplish objective 5. To initially elicit input from growers and other audiences as to the resources they would most prefer and likely use, our team distributed surveys at two professional conferences. A total of 41 responses were received from primarily growers (>55%), some researchers (~10%), and other professionals. Most rely on information from extension agents, websites, newsletters (via email), and professional conferences. Most were interested in information regarding management strategies and distribution maps, and preferred that information be in written or audio/visual format. We increased project awareness through the creation of a project name (FINDMe: Focused INvestigations on Distribution and management of Meloidogyne enterolobii), logo, branding guide, slide deck template, and ad in the 2020 Southern Vegetable Handbook. In addition, the team has developed a website (https://www.findmenematode.org/) and twitter account (https://twitter.com/FINDMeNematode) to increase awareness, educate target audiences, stay connected with other researchers, and disseminate knowledge generated. A listserv, email address ([e-mail]), and question form on our website will allow growers to connect to the project team and gain insight from experts.

Publications

• Type: Journal Articles Status: Published Year Published: 2020 Citation: Wong T. S. and Quesada-Ocampo L. M. (2020) Evaluation of SDHIs for control of southern root-knot nematode and fungal pathogens in watermelon. Phytopathology 110:S1.20.
• Type: Journal Articles Status: Published Year Published: 2020 Citation: Ye W, Schwarz T., Davis E. L., Thiessen L. D., Quesada-Ocampo, L. M., and Gorny A. M. (2020) Occurrence of the root-knot nematode Meloidogyne enterolobii infecting sweetpotato in North Carolina, United States. Phytopathology 110:S1.2.
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Collins H., Adams M. L., Parker B., and Quesada-Ocampo L. M. (2019) Evaluation of nematicides for control of Southern and Guava Root Knot Nematodes in sweetpotato, 2018. Plant Disease Management Reports 13: N030.
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Collins H., Adams M. L., Parker B., and Quesada-Ocampo L. M. (2019) Evaluation of nematicides for control of Southern Root Knot Nematodes in sweetpotato, 2018. Plant Disease Management Reports 13: N031.
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Keinath, A.P., W. P. Wechter, W. B. Rutter and P. Agudelo. 2019. Cucurbit rootstocks resistant to Fusarium oxysporum f. sp. niveum remain resistant when co-infected by Meloidogyne incognita in the field. Plant Disease 103:1383-1390.
• Type: Journal Articles Status: Under Review Year Published: 2020 Citation: Rutter, W. B., Wadl, P. A., Mueller, J. D. and P. Agudelo. 2020. Identification of Sweetpotato Germplasm Resistant to Pathotypically Distinct Isolates of Meloidogyne enterolobii from the Carolinas. Plant Disease (under review).
• Type: Journal Articles Status: Published Year Published: 2019 Citation: Rutter, W., A. Skantar, Z. Handoo, J. Mueller, S. Aultman and P. Agudelo. 2019. Meloidogyne enterolobii found infecting root-knot nematode resistant sweetpotato in South Carolina, United States. Plant Disease 103: 775.
• Type: Other Status: Published Year Published: 2020 Citation: Quesada-Ocampo L. M. (2018) Sweetpotato root knot nematode.Vegetable Pathology Factsheets. NC State Extension Publications. URL: https://content.ces.ncsu.edu/sweetpotato-root-knot-nematode. Revised 2020.
• Type: Other Status: Published Year Published: 2019 Citation: Joyce, A.L. and Thiessen, L.D. (2019) Root Knot Nematode of Soybean. Soybean Disease Information. NC State Extension Publications. URL: https://content.ces.ncsu.edu/root-knot-nematode-of-soybean?x=18774
• Type: Other Status: Published Year Published: 2019 Citation: Rosado Rivera, Y.I. and Thiessen, L.D. (2019) Root Knot Nematode of Cotton. Cotton Disease Information. NC State Extension Publications. URL: https://content.ces.ncsu.edu/cotton-root-knot-nematodes?x=22187
• Type: Websites Status: Published Year Published: 2020 Citation: https://www.findmenematode.org/
• Type: Conference Papers and Presentations Status: Other Year Published: 2020 Citation: Quesada-Ocampo L. M. Population genetics and epidemiology approaches for management of re-emerging pathogens of vegetable crops. Department of Plant Pathology, University of Minnesota, St. Paul, MN, September 2020. Oral Presentation.
• Type: Conference Papers and Presentations Status: Other Year Published: 2020 Citation: Quesada-Ocampo L. M. Management of re-emerging pathogens of vegetable crops through translational approaches. Department of Plant Pathology and Environmental Microbiology, Pennsylvania State University, University Park, PA, March 2020. Oral Presentation.
• Type: Conference Papers and Presentations Status: Other Year Published: 2020 Citation: Wong T. S. and Quesada-Ocampo L. M. Evaluation of SDHIs for control of southern root-knot nematode and fungal pathogens in watermelon. Annual Southern Division American Phytopathological Society Meeting, Charleston, SC, February 2020. Oral Presentation.
• Type: Conference Papers and Presentations Status: Other Year Published: 2020 Citation: Collins, H., Quesada-Ocampo, L. M. Evaluation of nematicides for control of Guava and Southern root knot nematodes in sweetpotato. National Sweetpotato Collaborators Group Annual Meeting, Nashville, TN, January 2020. Oral Presentation.
• Type: Conference Papers and Presentations Status: Other Year Published: 2019 Citation: Wong T. S. and Quesada-Ocampo L. M. Sensitivity of Meloidogyne incognita, Fusarium oxysporum f.sp. niveum, and Stagonosporopsis citrulli to succinate dehydrogenase inhibitors used for control of watermelon diseases. NC State Plant Pathology Symposium, Raleigh, NC, November 2019. Oral Presentation.
• Type: Conference Papers and Presentations Status: Other Year Published: 2019 Citation: Thiessen, L.D. Emerging Diseases of Cotton & Disease Management Considerations. Cotton Community Meeting, Raleigh, NC. October 2019. Oral Presentation
• Type: Conference Papers and Presentations Status: Other Year Published: 2019 Citation: Gorny A., Collins, H., and Quesada-Ocampo, L.M. Management of guava root knot nematode. North Carolina Vegetable Growers Association Ag Expo. Wilmington, NC, December 2019. Oral Presentation.
• Type: Conference Papers and Presentations Status: Other Year Published: 2019 Citation: Gorny A. Managing nematodes: From sampling to control options. North Carolina Agricultural Consultants Association Fall Conference. Raleigh, NC, December 2019. Oral Presentation.
• Type: Other Status: Other Year Published: 2020 Citation: Thiessen, L.D. Grains Disease Management. Pasquotank County Grains Meeting. Smithfield, NC. February 2020. Oral Presentation.
• Type: Other Status: Other Year Published: 2020 Citation: Thiessen, L.D. Soybean Disease Management. Johnston County Grains Meeting. Smithfield, NC. February 2020. Oral Presentation.
• Type: Conference Papers and Presentations Status: Other Year Published: 2020 Citation: Schwarz T., Collins H., Quesada-Ocampo, L. M. and Gorny A. Current management and control options for the aggressive root knot nematode, Meloidogyne enterolobii. American Phytopathological Society Annual Meeting, Plant Health 2020, Denver, CO, August 2020. Poster Presentation.
• Type: Conference Papers and Presentations Status: Other Year Published: 2020 Citation: Ye W, Schwarz T., Davis E. L., Thiessen L. D., Quesada-Ocampo, L. M., and Gorny A. M. Occurence of the root-knot nematode Meloidogyne enterolobii infecting sweetpotato in North Carolina, United States. Annual Meeting of the Southern Division-American Phytopathological Society, Charleston, SC. February, 2020. Poster Presentation.
• Type: Other Status: Other Year Published: 2020 Citation: Quesada-Ocampo, L. M. Cucumber diseases in the greenhouse. Greenhouse vegetable production agent training. Raleigh, NC, January 2020. Oral Presentation.
• Type: Other Status: Other Year Published: 2020 Citation: Thiessen, L.D. Soybean Disease Management. Northampton Grains Meeting. Jackson, NC. February 2020. Oral Presentation.
• Type: Other Status: Other Year Published: 2020 Citation: Thiessen, L.D. Soybean Disease Management. Hyde County Grains Meeting. Fairfield, NC. February 2020. Oral Presentation.
• Type: Other Status: Other Year Published: 2020 Citation: Thiessen, L.D. Soybean Disease Management. Beaufort Grain Meeting, Beaufort County. Bath, NC. January 2020. Oral Presentation.
• Type: Other Status: Other Year Published: 2019 Citation: Thiessen, L.D. Soybean Disease Management. Cleveland/Lincoln Grains Meeting, Lincolnton, NC. February 2019. Oral Presentation.
• Type: Other Status: Other Year Published: 2019 Citation: Thiessen, L.D. Soybean Disease Management. Guilford Grains Meeting, Greensboro, NC. February 2019. Oral Presentation.
• Type: Other Status: Other Year Published: 2019 Citation: Thiessen, L.D. Soybean Disease Management. Pasquotank Grains Meeting, Elizabeth City, NC. February 12, 2019. Oral Presentation.
• Type: Other Status: Other Year Published: 2019 Citation: Thiessen, L.D. Soybean Disease Management. Winter Grain Production Meeting, Onslow County. Jacksonville, NC. January 31, 2019. Oral Presentation.
• Type: Other Status: Other Year Published: 2019 Citation: Thiessen, L.D. Soybean Disease Management. Blacklands Road Show Production Meeting, Columbia, NC. January 30, 2019. Oral Presentation.
• Type: Other Status: Other Year Published: 2019 Citation: Thiessen, L.D. Soybean Disease Management. Winter Grain Production Meeting, Martin County. Williamston, NC. January 2019. Oral Presentation.
• Type: Other Status: Other Year Published: 2019 Citation: Thiessen, L.D. Soybean Disease Management. Blacklands Road Show Production Meeting, Chocowinity, NC. January 2019. Oral Presentation.
• Type: Other Status: Other Year Published: 2019 Citation: Gorny A., Collins H. and Quesada-Ocampo L. M. Control of rot knot nematode in sweetpotato. Sweetpotato field day. Kinston, NC, October 2019. Oral Presentation.
• Type: Other Status: Other Year Published: 2020 Citation: Gorny A. Management of the Guava root-knot and other nematodes in tobacco and vegetables. Organic Commodities and Livestock Conference. Raleigh, NC, February 2020. Oral Presentation.
• Type: Other Status: Other Year Published: 2019 Citation: Thiessen, L.D. Soybean disease management. Soybean Agent Training. Raleigh, NC. December 2019. Oral Presentation.
• Type: Other Status: Other Year Published: 2020 Citation: Thiessen, L.D. Cotton Disease Management. Cotton and Peanut Agent Training. Wilson, NC. January 15, 2020. Oral Presentation.
• Type: Other Status: Other Year Published: 2020 Citation: Thiessen, L.D. Soybean disease management. Piedmont Soybean Field Day. Piedmont Research Station, Salisbury, NC. October 2019. Oral Presentation.