NC_temp1197: Practical Management of Nematodes on Corn, Soybeans and Other Crops of Regional Importance

(Multistate Research Project)

Status: Draft Project

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NC_temp1197: Practical Management of Nematodes on Corn, Soybeans and Other Crops of Regional Importance

Duration: 10/01/2026 to 09/30/2031

Administrative Advisor(s):

Derek McLean

NIFA Reps:

Non-Technical Summary

Plant-parasitic nematodes (PPN) are ubiquitous pests and serve as a major constraint to agricultural production across the North Central Region (NCR). The NCR includes the major U.S. production areas of corn, soybeans, and small grains and is also home to major production sites for several vegetable crops (e.g. sugar beets, cucurbits, potatoes). Plant-parasitic nematodes cause yield loss in all of these production systems. The long-term goal of our committee is the effective and economic control of plant-parasitic nematodes in the NCR through the development and integration of management strategies, generation of fundamental knowledge of PPN and their impact on cropping systems relevant to the NCR and broadly applicable information disseminated to stakeholders. The target audience of this work include growers, crop consultants, breeders, industry professionals, and Extension personnel. This coordinated work increases individual committee member impact and provides a base for synergistic collaborations that include work on seed treatments, resistance cultivar breeding, nematicide development, biological control, integrated pest management practices, basic biology and more to lead to increased education and sustainable management of these significant agricultural pests.

Statement of Issues and Justification

Unbiased, experimental data is essential for effective management of plant-parasitic nematodes as is its accessibility for use by growers, crop consultants, breeders, industry professionals, and Extension personnel. Plant-parasitic nematodes are among the most economically damaging pests of agronomic crops in the NCR, with the soybean cyst nematode (SCN; Heterodera glycines) consistently ranked as the most yield-limiting pathogen of soybean in the U.S. SCN alone is responsible for an estimated 100 million bushels in annual soybean losses, and other nematode species (e.g., Rotylenchulus reniformis, Belonolaimus longicaudatus, Meloidogyne, Helicotylenchus, Hoplolaimus, Paratrichodorus, and Pratylenchus spp.) dessimate an additional tens of millions of bushels lost each year. Plant-parasitic nematodes also rank among the top ten most destructive pests of corn in the U.S., causing hundreds of tens of millions of bushels in cumulative losses. Many of these nematodes also compromise other regionally important crops, including wheat, alfalfa, and numerous vegetable commodities. To improve food security and support informed decision-making, this project addresses key applied and fundamental questions related to nematode biology, distribution, and yield loss across all major affected crops in the NCR.

The Importance of this Work, and the Consequences if Not Done

Plant-parasitic nematodes are ubiquitous and widely distributed across the North Central Region (NCR), yet their impacts substantially vary due to differences in nematode population biology, soil types, cropping systems, climate, and management practices. This regional variability complicates nematode diagnoses and often leads to yield losses being misattributed to other factors such as nutrient deficiencies, soil quality issues, or other diseases. Lack of information and engagement to inform stakeholders of the importance of plant parasitic nematodes ultimately reduces management efficacy and costing growers’ significant revenue.

Because nematode populations and environmental conditions differ across the NCR, coordinated, multi-state research is essential for generating accurate recommendations and advancing nematode management strategies. This collaboration enables synchronized experimental design, meaningful cross-state data comparison, and a deeper understanding of how environmental variability shapes nematode biology and management decisions. Without this coordination, opportunities to develop effective, regionally relevant control strategies would be lost, slowing scientific progress and limiting stakeholders’ access to unbiased, rigorous experimentally informed material. This work allows for the continuous development of and progression of nematode management strategies, related technologies and extension efforts that address the constant and ever-changing threats of nematodes to agriculture in the NCR.

The Technical Feasibility of the Research

All proposed objectives rely on standard nematology techniques, and the members of this technical committee collectively represent the primary nematology expertise across the NCR. Their extensive backgrounds include prior accomplishments such as standardizing nematode extraction methods, evaluating resistance in commercial cultivars, assessing nematode-protectant seed treatments, and establishing risk thresholds for plant-parasitic nematodes on corn, soybean and other crops of regional importance. Committee members are also well positioned to integrate emerging nematode management technologies into established production systems. Many have substantial Extension responsibilities, enabling effective dissemination of research findings, and several serve as co-PIs on the United Soybean Board–funded “SCN Coalition,” which delivers soybean cyst nematode management education to growers and agricultural industry stakeholders.

The Advantages for Doing the Work as a Multistate Effort

As plant-parasitic nematodes do not recognize state, district or county borders, understanding their biology and management requires coordinated, multistate research efforts. In a multistate effort, nematode research and extension can be focused regionally, based on soil types, major crops and environmental factors. Soybean cyst nematode (SCN) is found throughout the NCR (Tylka and Marett, 2017), however, populations vary significantly in their ability to overcome host resistance (Niblack et al., 2009). Collaborative research across the region enables harmonized experimental designs and meaningful data comparisons, which are essential for developing management strategies that are robust across diverse environments and enable this information to serve a large swatch of the NCR stakeholder base. This integration of expertise among nematologists and plant pathologists accelerates scientific progress, particularly given that NCR institutions employ roughly only one faculty nematologist. Multistate coordination allows for increased communication and sharing of expertise that varies greatly among the technical committee.

This coordinated regional approach also improves our capacity to detect and interpret geographical differences in nematode biology, host interactions, and management outcomes. These comparisons provide broader insight into how soil conditions, nematode biology, cropping systems, and other agronomic factors influence nematode pressure and management efficacy. For example, while SCN is widespread in the NCR (Tylka and Marett, 2017), the performance of certain nematode-protectant seed treatments may depend on interactions with additional geographically restricted pathogens (Bissonnette et al., 2020). Understanding these context-dependent effects is critical for developing effective, economically sound management strategies. Given the declining number of nematology and plant pathology faculty at land-grant institutions, coordinated multistate research is essential to maintain progress in the field and to continue delivering unbiased, relevant recommendations to stakeholders across the region through pooled resources and increased communication.

What the Likely Impacts will be from Successfully Completing the Work

This project will advance environmentally and economically sustainable crop production by reducing yield losses caused by plant-parasitic nematodes across the NCR. Even a conservative estimate of 1% yield loss translates to roughly $950 million in annual production losses, and plant-parasitic nematodes in corn and soybean alone are responsible for more than $1.5 billion in yearly economic losses (Plumblee and Mueller, 2021). In the NCR, over 8 million acres are chemically treated for nematode control each year (USDA NASS 2017), underscoring both the scale of the problem and the need for improved integrated and sustainable management strategies. By combining applied and fundamental research with coordinated outreach efforts, this project will enhance near- and long-term nematode management, ultimately supporting higher yields, reduced economic losses, and more sustainable production systems.

Related, Current and Previous Work

This renewal proposal for NC1197 will supplement and extend current fundamental and applied knowledge regarding the management of plant-parasitic nematodes relevant to the region and cropping systems of the NCR. The proposed multistate research project is a continuation of a longstanding collaboration among NCR nematologists and plant pathologists to address the ever-changing challenges due to plant-parasitic nematodes on important crops within the region. A complete listing of accomplishments from the previous five-year period is available from yearly reports. Below is a subset of accomplishments during the previous project period of 2021 - 2025:

NC1197 members were involved in the “SCN Profit Checker” which was released through The SCN Coalition; this online tool that helps farmers better understand the losses caused by soybean cyst nematode on their own form on a field-by-field basis.
Members of NC 1197 contributed towards the summarization of 51 site-years of field research focused on management of soybean cyst nematode with nematode protectant seed treatments (Bissonnette et al. 2024. Plant Dis. 108:1729-1739).
The effectiveness of an automated soil sampler in measuring soybean cyst nematode abundance was demonstrated in Ohio, which can lead to more efficient methods of detecting and monitoring important plant parasitic nematodes across the North Central region.
Evaluated thousands of SCN resistant soybean cultivars and breeding lines for their efficacy of resistance to SCN.
Determined root-lesion nematode host range of commercial crops and cover crops to improve management recommendations and produced genome assemblies of this nematode.
NC1197 Members contribute to the Crop Protection Network to provide annual state-level yield loss estimates caused by SCN and other pathogens.

Other multistate committees also address plant-parasitic nematodes (NE1640, W4186 and S1092). However, these projects give substantial effort to nematodes and crops relevant to different regions with different nematode populations and cropping systems, and largely focus on the Northeast, Southern and Western regions. For example, W4186 examines Meloidogyne chitwoodi, a species that is absent from the NC region. While some of the nematode taxa studied will overlap, the crops and agricultural systems differ substantially among these regions. There is also some overlap with the NCERA137 committee on soybean diseases, which includes monitoring of plant-parasitic nematodes on soybeans. Despite this overlap, our committee is pursuing research on nematodes beyond soybeans. Similarly, NCERA137 focuses on a broad range of pathogens to soybean. Given the overlap with NCERA137, we will attempt to coordinate an annual meeting with that group during the upcoming project period to best coordinate future research directions.

Beyond the evaluation of traditional management tactics, NC 1197 researchers are actively exploring innovative technologies and complex ecological interactions to develop more integrated and sustainable SCN management paradigms. This forward-looking research is focused on improving the efficiency of SCN and other PPN detection and on understanding the intricate relationships between SCN, other nematodes, soil health, and cropping system productivity.

Automated Sampling

An Ohio-based study compared an automated soil sampler to traditional hand sampling for measuring SCN abundance. The results showed a significant positive relationship between the two methods at two locations, The study demonstrates the potential for using automated technologies to efficiently map SCN population densities across large fields (Gonzalez Aquino et al., 2024)

Molecular Diagnostics

Committee members have developed a quantitative real-time PCR assay designed from a nematode-secreted effector gene that can both differentiate SCN from the closely related sugar beet cyst nematode and quantify SCN egg numbers directly from soil DNA extracts. This molecular tool showed a high correlation with conventional egg counting methods, offering a path toward more rapid and precise diagnostics (Baidoo and Yan, 2021)

Soil Health Interactions

A growing area of research is investigating how SCN populations are influenced by the broader soil ecosystem. This research seeks to determine if specific microbial communities can create suppressive soils, offering a potential path toward naturally regulating SCN populations.

In Michigan, researchers are using the Soil Food Web (SFW) model to analyze nematode community structure and its relationship to soil health under various regenerative agricultural practices. Complementary research in Ohio, detailed in Medina López et al. (2024), has examined the link between SCN abundance and corresponding shifts in soil fungal communities, providing new insights into the nematode's ecological impact. Other relevant works include those aimed at understanding soil food web as a diagnostic tool and composition and function of bacterial communities impacting nematode disease (Lartey et al., 2025).

Cover Crop Impacts

Several studies are evaluating the potential for cover crops to actively manage SCN. An experiment in North Dakota found that faba bean, a non-host for SCN, induced significant nematode egg hatching but prevented the juveniles from developing into reproductive adult females, indicating its potential as a "trap crop." (Acharya et al., 2021). In Minnesota, ongoing field experiments with pennycress as a winter cover crop have, to date, observed no increase in SCN population densities, suggesting it can be safely integrated into rotations.

Efficacy of Seed Treatments

Nematode-protectant seed treatments have become increasingly prevalent in the agricultural marketplace as an additional tool for managing SCN. However, their performance can be variable, necessitating unbiased, multi-environment field trials to provide growers with reliable data on their efficacy and economic viability. NC 1197 members have addressed this need through extensive, coordinated research across the region.

The primary finding from a large-scale effort was formally substantiated in a peer-reviewed publication by Bissonnette et al. (2024), which synthesized data from 51 site-years of uniform testing. This analysis quantified a conclusion first articulated in the 2022 project report: "No one seed treatment was found to be the silver bullet." This finding highlights the inconsistent performance of these products and underscores that they are not a substitute for sound management practices like crop rotation and the use of resistant cultivars. Future work will continue to examine the efficacy of seed treatments, including impacts on virulence phenotypes (Barizon et al., 2025).

Evaluating Host Plant Resistance and Nematode Distribution and Virulence

Host plant resistance remains the cornerstone of SCN and other PPN management, offering the most effective and economical means of protecting soybean and other crops in the NCR. Given the widespread erosion of the efficacy of the PI 88788 resistance source, a primary objective of this proposal is the rigorous evaluation of commercial and pre-commercial soybean cultivars and germplasm. This work is vital for identifying durable sources of resistance and providing growers with reliable performance data to counter virulent SCN populations.

Continual monitoring efforts are strategically essential for understanding the geographic spread, population densities, and virulence dynamics of SCN. The data gathered from these surveys directly inform management recommendations for growers, guide the development of state-level extension resources, and help establish critical priorities for soybean breeding programs.

Recent surveys conducted by NC1197 committee members confirm the magnitude and severity of SCN infestations across the North Central region, revealing a narrative of escalating threat. While a 2018-2022 survey found SCN in 84% of Kentucky fields, more recent 2024 data from 488 samples across 35 counties highlights the severity, with 38% of fields containing populations at or above 500 eggs/100 cm³ soil, a threshold for potential yield loss. The scale of infestation is further illustrated by a comprehensive survey of 1,019 growers' fields in Illinois and by results from Missouri, which indicated exceptionally high infestation levels: 45% of samples had SCN populations exceeding 4,000 eggs/100 cm³ of soil, while only 17% had fewer than 200 eggs/100 cm³. Compounding these high densities is an alarming multi-year trend documented in Kansas, where SCN prevalence has increased from 15% to 35% over the past decade. Ongoing surveys in South Dakota and Ohio continue to map the nematode's footprint, with South Dakota confirming new county-level infestations and Ohio processing over 450 samples in 2024 alone. Importantly, hypervirulent populations of SCN are continuing to dominate soybean growing regions in the NCR.

Conclusion

A unified, synergistic and wholistic approach is needed to address the many variable facets of developing and conveying informed and practical management of nematodes on corn, soybean and other crops of importance in the NCR. The proposed and sustaining collaborative research is beneficial and indispensable for developing agile, science-based solutions required to ensure the long-term profitability and sustainability of NCR crop production facing nematode threats.

Objectives

Develop, evaluate, improve, and integrate management techniques for plant-parasitic nematodes of significance in the north-central region (NCR) to increase grower profitability.
Examine impact of plant parasitic nematodes on cropping system sustainability through analyses of interactions with plant health, abiotic stressors and other microbes, including other potential pathogens.
Develop and broadly disseminate research-based information on the biology and management of plant-parasitic nematodes of economically important crops in the NCR.

Methods

Objective 1: Develop, evaluate, improve, and integrate management techniques for plant-parasitic nematodes of significance in the north-central region (NCR) to increase grower profitability.

A. Evaluate interactions of plant-parasitic nematodes with germplasm of economically important crops.

Soybean germplasm will be screened for cyst nematode resistance using standardized protocols (Niblack et al. 2009) to expand the diversity of available resistant lines and support breeding strategies such as gene stacking and incorporation of wild soybean alleles. Soybean cultivars will be evaluated under greenhouse and field conditions for resistance to SCN, and germplasm from other major regional crops, including corn, wheat, potatoes and other vegetables, will be screened for resistance to root-lesion, lance, and other important and relevant nematode species.

B. Assess intraspecific variability in nematode virulence and pathogenicity.

SCN populations from participating states will continue to be evaluated using the HG type test (Niblack et al. 2002) to characterize virulence and assess the durability of available resistance sources. Greenhouse and field experiments will also quantify virulence variation in other plant-parasitic nematode species by measuring initial and final population densities on specific host varieties to inform the utility of emerging resistance sources and help predict the durability of nematode management strategies.

C. Evaluate new commercial products and innovative strategies for nematode control.

A wide range of commercial products that can include nematode-protectant seed treatments and biological control agents will be evaluated using laboratory, greenhouse, and field experiments. As new products enter the marketplace, unbiased performance data will be generated to guide stakeholder decision-making. Trials will also assess interactive effects among different management products and with co-occurring pathogens. Yield data collected across the region will be incorporated into meta-analyses to generate robust recommendations that are relevant to stakeholders across the NCR.

C. Develop innovative methods to detect and quantify plant-parasitic nematodes.

Traditional nematode detection relies on labor-intensive soil and root extractions followed by microscopic identification. To improve diagnostic efficiency, this project will develop molecular and artificial intelligence-based identification and quantification tools for economically important nematode species. As new insights into SCN virulence genes emerge, these will be integrated into molecular detection strategies to enhance early identification of virulent populations.

Objective 2: Examine impact of plant parasitic nematodes on cropping system sustainability through analyses of interactions with plant health, abiotic stressors and other microbes, including other potential pathogens.

A. Investigate pest and disease interactions involving plant-parasitic nematodes.

Plant-parasitic nematodes often interact synergistically with other pathogens to intensify disease severity. Experiments in greenhouse and field environments will examine co-pest interactions such as SCN with Fusarium virguliforme (sudden death syndrome) and Macrophomina phaseolina, as well as root-lesion nematodes with Verticillium dahliae in potato. Interactions among nematode species within cropping systems will also be evaluated to understand combined impacts on plant health and yield.

B. Determine the temporal and spatial dynamics of nematodes in relation to plant and soil health.

Soil samples will be regularly collected over time to quantify nematode communities by trophic group (herbivore, bacterivore, fungivore, predator, omnivore). These data will support analyses of nematode diversity and the soil food web structure that are critical to soil and crop yield and health. Multivariate analyses (e.g., PCA) will identify correlations among soil types, nematode community indices, and crop performance.

Objective 3: Develop and broadly disseminate research-based information on the biology and management of plant-parasitic nematodes of economically important crops in the NCR.

A coordinated multistate outreach effort will ensure consistent messaging on the importance of nematode management and effective control strategies. Outreach will include grower meetings, extension publications, webcasts, and press releases distributed broadly across the NCR. Committee efforts will complement and amplify programming from the SCN Coalition, with the long-term goal of expanding into other important and relevant nematodes to the NCR.

Measurement of Progress and Results

Outputs

Extension and other non-peer reviewed publications providing unbiased data on the management of plant-parasitic nematodes.
Peer-reviewed publications detailing experiments targeting one or more of the proposal objectives to further fundamental knowledge of plant parasitic nematodes relevant to the NCR
Improved methodologies for the extraction and identification of plant-parasitic nematodes
regional database of germplasm with resistance or tolerance to plant-parasitic nematodes of importance

Outcomes or Projected Impacts

Increased number of resistant cultivar options for growers and breeders to manage plant-parasitic nematodes
Improved efficiency in diagnosis of plant-parasitic nematode issues as measured by turnaround time for processing of samples and delivering reports
Increased profitability for growers through reduced plant-parasitic nematode damage
Increased stakeholder awareness of plant-parasitic nematodes and strategies to manage these important and often overlooked crop pests

Milestones

(2026):A. Identify coordinators for each sub-objective. B. Identify potential extramural funding for each sub-objective. C. Begin laboratory, greenhouse and field experiments for (Objectives 1 and 2).

(2027):A. Continue laboratory, greenhouse and field experiments for (Objectives 1 and 2). B. Apply for extramural funding. C. Perform preliminary analysis of 2026 - 2027 data.

(2028):A. Continue laboratory, greenhouse and field experiments (Objectives 1 and 2). B. Apply for extramural funding. C. Perform preliminary analysis of 2026 - 2028 data. D. Summarize findings for stakeholders (Objective 3) based on 2026 - 2027 data.

(2029):A. Continue laboratory, greenhouse and field experiments (Objectives 1 and 2). B. Perform preliminary analysis of 2026 - 2029 data. D. Summarize findings for stakeholders (Objective 3) based on 2026 - 2028 data.

(2030):A. Continue laboratory, greenhouse and field experiments (Objectives 1 and 2). B. A Identify potential extramural funding for each sub-objective to support continued work on Objectives 1 and 2. C. Perform preliminary analysis of 2026 - 2030 data. D. Summarize findings for stakeholders (Objective 3) based on 2026 - 2029 data.

(2031):A. Conclude data analyses from laboratory, greenhouse and field experiments. B. Submit and revise manuscripts to peer-reviewed journal regarding Objectives 1 and 2. C. Summarize findings for stakeholders (Objective 3) based on complete data analysis (Years 2026 - 2030).

Projected Participation

View Appendix E: Participation

Outreach Plan

Objective 3 directly addresses our plan for outreach. Our audience includes growers, commodity groups, agribusinesses, regulatory agencies, and scientists in industry, government and academia. We will tailor our outreach for the most appropriate audience and for broad audiences. For example, the SCN-resistant soybean cultivar information will be of greatest use and interest to growers and agribusinesses. In some individual states/provinces, this information will be disseminated in hard-copy form, published and disseminated by commodity groups. Individual states/provinces will publish applied research results annually through extension outlets, including traditional extension publications, bulletins and newsletters, and web sites. Again, these reports will be gathered for region-wide public access via the internet. Information generated through the fundamental research will be disseminated through refereed research outlets such as the Journal of Nematology, Plant Disease, Plant Health Progress, Phytopathology, and other scientific publications.

Organization/Governance

The Chair and Secretary will be nominated and elected by committee members for one year terms to increase participation and inclusivity. Administrative guidance will be provided by an assigned Administrative Advisor and a NIFA Representative

Literature Cited

Acharya, K., Yan, G., & Plaisance, A. (2021). Effects of cover crops on population reduction of soybean cyst nematode (Heterodera glycines). Plant Disease, 105(4), 764-769.

Baidoo, R., & Yan, G. (2021). Developing a real-time PCR assay for direct identification and quantification of soybean cyst nematode, Heterodera glycines, in soil and its discrimination from sugar beet cyst nematode, Heterodera schachtii. Plant Disease, 105(12), 3848-3857.

Barizon, J., Bissonnette, K., Biggs, M., Haafke, A., & Bish, M. (2025). Influence of Heterodera glycines Virulence Phenotypes on the Performance of Nematode-Protectant Seed Treatments. Journal of nematology, 57(1).

Bissonnette, K. M., Barizon, J., Adee, E., Ames, K. A., Becker, T., Biggs, M., ... & Tenuta, A. U. (2024). Management of Soybean Cyst Nematode and Sudden Death Syndrome with Nematode-Protectant Seed Treatments Across Multiple Environments in Soybean. Plant Disease, 108(6), 1729-1739.

Bissonnette, K. M., Marett, C. C., Mullaney, M. P., Gebhart, G. D., Kyveryga, P. M., Mueller, T. A., & Tylka, G. L. (2020). Effects of ILeVo seed treatment on Heterodera glycines reproduction and soybean yield in small-plot and strip-trial experiments in Iowa. Plant Disease, 104(11), 2914-2920.

González Aquino, R. S., Mondal, S., Lovejoy, K., & Lopez-Nicora, H. D. (2024). Enhancing prediction of soybean cyst nematode spatial distribution through geostatistical optimization: A comparison of manual and automated sampling methods. Plant Disease, (ja).

Lartey, I., Benucci, G. M., Marsh, T. L., Bonito, G. M., & Melakeberhan, H. (2025). The Composition and Function of Bacterial Communities Associated with the Northern Root-Knot Nematode (Meloidogyne hapla) Populations Showing Parasitic Variability. Microorganisms, 13(3), 487.

López, M. M., Lopez-Nicora, H. D., & Ponce, M. S. B. (2024). Fungal communities shift with soybean cyst nematode abundance in soils. Phytobiomes Journal, 8(4), 568-577.

Niblack, T. L., Arelli, P. R., Noel, G. R., Opperman, C. H., Orf, J. H., Schmitt, D. P., ... & Tylka, G. (2002). A revised classification scheme for genetically diverse populations of Heterodera glycines. Journal of nematology, 34(4), 279.

Niblack, T. L., Tylka, G. L., Arelli, P., Bond, J., Diers, B., Donald, P., ... & Wilcox, J. (2009). A standard greenhouse method for assessing soybean cyst nematode resistance in soybean: SCE08 (standardized cyst evaluation 2008). Plant Health Progress, 10(1), 33.

Plumblee, M. T., & Mueller, J. D. (2021). Implementing precision agriculture concepts and technologies into crop production and site-specific management of nematodes. In Integrated Nematode Management: State-of-the-art and visions for the future (pp. 421-427). Wallingford UK: CABI.

Tylka, G. L., & Marett, C. C. (2017). Known distribution of the soybean cyst nematode, Heterodera glycines, in the United States and Canada, 1954 to 2017. Plant health progress, 18(3), 167-168.

Attachments

Land Grant Participating States/Institutions

IL, KS, KY, MO, SD

Non Land Grant Participating States/Institutions