Source: CLEMSON UNIVERSITY submitted to
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
NEW
Funding Source
Reporting Frequency
Annual
Accession No.
1020264
Grant No.
2019-51181-30018
Project No.
SC-2019-03136
Proposal No.
2019-03136
Multistate No.
(N/A)
Program Code
SCRI
Project Start Date
Sep 1, 2019
Project End Date
Aug 31, 2023
Grant Year
2019
Project Director
Agudelo, P.
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
0%
Research Effort Categories
Basic
30%
Applied
50%
Developmental
20%
Classification

Knowledge Area (KA)Subject of Investigation (SOI)Field of Science (FOS)Percent
21214991120100%
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 08/31/20

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 (findmenematode@gmail.com), 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.