W5186: Variability, Adaptation and Management of Nematodes Impacting Crop Production and Trade

(Multistate Research Project)

Status: Active

SAES-422 Reports

Annual/Termination Reports:

[01/11/2024]

Date of Annual Report: 01/11/2024

Report Information

Annual Meeting Dates: 11/13/2023 - 11/14/2023
Period the Report Covers: 01/12/2022 - 01/11/2023

Participants

Brief Summary of Minutes

Accomplishments

<p><strong>Objective 1- </strong><em>characterize genetic and biological variation in nematodes relevant to crop production and trade</em></p><br /> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <strong>Activities </strong>in Idaho include an initiative to explore genetic diversity within <em>Globodera</em> spp. Different nematode populations are classified into pathotypes based on their reproductive capacity on specific potato genotypes harboring known resistance genes. The pathotypes of 10 populations from Peru were characterized using a set of potato differential lines containing different resistance genes. One <strong>outcome </strong>of this research is that, according to the pathotype scheme, the Idaho <em>G. pallida</em> population is pathotype 2/3 (Pa2/3) (Phillips and Blok 2008). The continuous use of resistant potatoes may encourage the emergence of more virulent populations (Varypatakis et al. 2020). It has been shown that cyst nematode resistance derived from <em>Solanum tuberosum spp. andigena</em> is more readily overcome than resistance from <em>S. vernei</em> (Phillips and Blok 2008;&nbsp; Phillips and Blok 2012). Recent evidence indicates that different individuals within a cyst may exhibit varying virulence traits, possibly contributing to the breakdown of resistance. Other ongoing <strong>activities </strong>in Idaho involve genetically characterizing samples of Bolivian<em> Globodera</em> spp.&nbsp; The University of Idaho has set up one experiment in Bolivia to phenotype for resistance to 3 populations of <em>Globodera</em>. An <strong>output </strong>of this research is that it has equipped Idaho scientists with the ability to identify appropriate sources of resistance that encompass cyst nematode population diversity.</p><br /> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <strong>Activities</strong> on root-knot nematode (RKN) genomes/transcriptomes have led to insights on the genetic factors governing nematode parasitism and virulence. For example, work at UC Davis centers on two closely related strains of <em>M. javanica</em> (VW4 and VW5), which differ in their ability to parasitize tomato carrying <em>Mi-1</em>. &nbsp;The tomato gene <em>Mi-</em><em>1</em> confers resistance to three commonly occurring, damaging species of RKNs (Kaloshian and Teixeira 2019). On susceptible tomato, there is a reduced egg count on VW5-inoculated plants compared to VW4, indicating reduced fitness of the resistance-breaking strain. The previous reference genome <em>M. javanica</em> was not sufficient to allow resolution of the homeologous genomes. An <strong>output</strong> of the research has been a reference genome for VW4 and VW5 using a combination of HiFi, Hi-C, Iso-seq, and/or NanoPore sequencing. The sequencing data suggest that <em>M. javanica</em> is a hypotetraploid, and VW5 is missing a substantial DNA portion in a subgenome. An <strong>outcome</strong> of this research is that it lays important groundwork for identifying an avirulence gene in RKNs, a significant breakthrough for RKN research.</p><br /> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Advancements in molecular methods for RKN identification within and between species have also been achieved under this objective (Bogale et al. 2020;&nbsp; Powers et al. 2017;&nbsp; Powers et al. 2014). <strong>Activities</strong> include work on <em>M. chitwoodi</em>, a nematode that infects potato tubers. Transcriptome and genome analyses of <em>M. chitwoodi</em>-infected potato were performed, and an <strong>output</strong> was the identification of nematode parasitism genes (i.e. effector genes) that facilitate infections of potato (Zhang and Gleason 2021). More recently, the glands from <em>M. chitwoodi </em>were isolated for a gland-specific transcriptome analysis, laying the foundation for novel nematode effector identification in the coming year. Additional <strong>outputs </strong>from the <em>M. chitwoodi</em> genome data include a LAMP assay that can provide a quick DNA-based detection method for potato-infecting root-knot nematodes (Zhang and Gleason 2019) and a molecular beacon assay that allows researchers to easily distinguish between <em>M. chitwoodi, M. minor,</em> and<em> M. fallax</em> (Anderson and Gleason 2023). Within the <em>M. chitwoodi</em> species, three major populations (Race 1, Race 2, and Roza) exist in the Pacific Northwest, varying in virulence and host range. An <strong>output</strong> of the research has been that PCR markers were developed based on the genetic variability between these races, allowing scientists to determine that Race 1 and Roza were the predominant strains in Eastern Washington (Hu et al. 2023).</p><br /> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;Other major <strong>outputs</strong> include advances in nematode identification by molecular &lsquo;barcoding&rsquo; approaches. Ongoing<strong> activities</strong> in the working group aim to refine and define the conditions and limitations of DNA barcoding using the COI mitochondrial gene. A major <strong>outcome </strong>from the group was a DNA barcoding reference database called NemaTaxa was developed as a comprehensive reference database of nematodes in US agriculture (Baker et al. 2023). Moreover, work conducted in Nebraska supports a field device for rapid identification of cyst nematode juveniles, accelerating the time of species identification and reducing diagnostic expenses. Another <strong>output</strong> from this objective involves developing a metabarcoding approach for entomopathogenic nematode (EPN) identification from soil communities. Tests are underway to convert the current Sanger sequencing approach of DNA barcoding to a community-based method applicable to numerous nematode specimens in a single analysis (Gendron et al. 2023).</p><br /> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Continued <strong>activities</strong> in detecting and diagnosing plant parasitic nematodes provides valuable management insights to regional agricultural communities. With regards to nematodes as environmental indicators, researchers in Nebraska are working on a set of soil samples that were affected by a major contamination event associated with an ethanol production facility. An <strong>outcome</strong> of this work is the crucial understanding of measurable disturbances in nematode communities within soil health due to environmental contamination.</p><br /> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <strong>Final </strong><strong>Outcomes: Studies of the genetic diversity and virulence of nematodes led to the development of innovative molecular tools for nematode detection, offering practical solutions for managing nematode infestations and preserving crop health</strong>. <strong>Additionally, the advancements in nematode identification methodologies and their role as environmental indicators enhanced agricultural sustainability and soil management practices.</strong></p><br /> <p>&nbsp;</p><br /> <p><strong>Objective 2:</strong><em> nematode adaptation processes to hosts, agro-ecosystems and environments</em></p><br /> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;Research <strong>activities </strong>at UC-Riverside are heavily focused on developing and analyzing resistance traits against RKNs in both carrot and cowpea. One of the <strong>outputs</strong> from W-4186 researchers is that they found resistance markers against <em>M. hapla</em> in the carrot cultivar &ldquo;Homs.&rdquo; However, the specific avirulence gene(s) of <em>M. hapla </em>involved in this interaction still need to be pinpointed. Nevertheless, an <strong>outcome</strong> from identifying natural host resistance traits is their promise for adoption in plant breeding programs. Another <strong>outcome</strong> from the cowpea genome work in this project has been the identification of root-knot nematode resistance traits on four of the 11 cowpea chromosomes (Lonardi et al. 2019;&nbsp; Ndeve et al. 2019). Specifically, single resistance traits were found for resistance to&nbsp;<em>M. javanica</em>&nbsp;and or&nbsp;<em>M. incognita</em>&nbsp;on chromosomes 1, 3 and 11 (Lonardi et al. 2019). Notably, when nematodes are cultured on resistant cowpea, there was a&nbsp; rapid selection for virulence (Petrillo et al. 2006). An <strong>output </strong>of this data is the observation of fluctuation in nematode populations upon the deployment of resistant cowpea.</p><br /> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <strong>Activities</strong> from W-4186 scientists at UC Davis include experiments on the <em>Mi</em>-resistance breaking <em>M. javanica </em>strain VW5. The VW5 nematode is less fit on susceptible crops than the avirulent <em>M. javanica</em> strain VW4. This discovery indicates that the acquisition of virulence in nematodes can be detrimental in the absence of resistance. This insight bears significant implications for the strategic deployment of resistant tomato cultivars.</p><br /> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; &nbsp;Nematode adaptation processes studied in this objective have also included how nematodes spread and adapt to new environments. An <strong>outcome</strong> of previous research in this project has been a demonstration of how snails and slugs were associated with at least 6 genera of plant-parasitic nematodes, potentially spreading the nematodes to new environments.&nbsp;In terms of finding nematodes in new environments, there have been major <strong>outcomes </strong>regarding nematode first reports. <strong>Activities</strong> in this area include surveys that have established a first report of <em>Ditylenchus dipsaci</em>&nbsp;in alfalfa in NM, alfalfa cyst nematode&nbsp;(<em>Heterodera medicaginis</em>) in KS, MT and UT, cactus cyst nematode (<em>Cactodera cacti</em>) in ID and Co, and <em>Cactodera milleri</em>&nbsp;from Quinoa fields in CO (Powers et al. 2019). An expansion of the NM identified an&nbsp;<em>Anguinidae</em>&nbsp;(new species) associated with displacement of native grasses by invasive plant species. The University of Hawaii conducted surveys on native plants in areas surrounding their campus to assess susceptibility to root-knot and reniform nematodes. Their findings suggested that the native plant Ipomoea appeared to be a good host, whereas most native plants seemed to be poor hosts for these nematodes.</p><br /> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Additional <strong>outputs</strong> from research in this Objective include novel data connecting changes in landscape usage,&nbsp; nematode communities, and soil health across various geographical regions. It is believed that nematode adaptation within agroecosystems is influenced by a combination of agricultural practices (APs) and alterations in biophysicochemical conditions within these systems. <strong>Activities </strong>include soil health assessments that are being conducted near Mead Nebraska, at the site of a major contamination event occurred during the course of a commercial enterprise developed to extract ethanol from unsold treated seed. Ongoing studies aim to assess the impact of applying 1,900 tons of "wetcake" solid waste to fields within the Eastern Nebraska Research and Extension Center.</p><br /> <p>Lastly, Michigan State University (MSU) researchers have participated in <strong>activities</strong> in which they have applied the soil food web (SFW) model to establish that <em>M. hapla</em> presence in mineral and muck soils was associated with either disturbed and/or degraded soil health conditions (Lartey et al. 2021), and populations with higher pathogenic variability (PV) came from degraded mineral soils (Lartey et al. 2022). Collectively, these results provide a significant <strong>outcome</strong>: a foundation for an in-depth understanding of the environment where <em>M. hapla </em>exists, conditions associated with PV, and designing suitable management strategies.</p><br /> <p><strong>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Final Outcomes: New data was obtained on how nematodes adapt to different hosts, agro-ecosystems, and environments. Our investigations have uncovered significant levels of nematode adaptation, particularly in their ability to parasitize resistant host plants, thrive in diverse soil conditions, and spread to new areas.</strong></p><br /> <p><strong>&nbsp;</strong></p><br /> <p><strong>Objective 3: </strong><em>Developing and assessing nematode management strategies in agricultural production systems</em></p><br /> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <strong>Activities</strong> under this objective have focused on four major themes: 1) novel biotechnology, 2) resistance and cropping systems, 3) biological controls and nematicides, and 4) decision-making models that translate complex biophysicochemical changes in the oil food web (SFW) into practical application.</p><br /> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Biotechnology offers new approaches to nematode control and will reduce the reliance on nematicides, which are often expensive and damaging to human health and the environment. For example, <strong>activities </strong>from researchers at UC-Riverside include screening a panel of rice varieties for nematode resistance. By using &lsquo;omics technologies, one of the <strong>outcomes</strong> is that they are able to link the expression of rice fitness/defense related genes to a nematode resistance phenotype. Using &ldquo;omics&rdquo; for developing nematode management has been a long-standing strategy for this working group. New molecular nematologists have joined W-4186 (now W-5186) in Indiana, Arkansas, and Wisconsin to continue to study the &ldquo;omics&rdquo; of plant responses to nematode parasitism.</p><br /> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; In addition to biotechnology to generate new nematode control tools, there are several examples in the working group highlighting research in nematode-cropping systems. Researchers in Alabama have performed <strong>activities </strong>around new cotton cultivars and their responses to <em>M. incognita</em> and <em>R. reniformis </em>infections. Their studies on resistant and susceptible cotton varieties with additions of seed treatments and in-furrow nematicides have helped to determine what strategies produce the best yield responses. One of the <strong>outcomes </strong>of this specific research was that the resistant varieties showed significantly increased yield, but the addition of nematicides further enhanced yields of the resistant varieties (Turner et al. 2023).</p><br /> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; In Idaho, cropping systems using a combination of resistant varieties and trap crops are being developed for control of <em>G. pallida</em>. Idaho specific <strong>activities</strong> include the assessment of the impact of <em>Solanum sisymbriifolium</em> and quinoa as trap crops for <em>G. pallida</em>. Although <em>S. sisymbriifolium</em> is highly effective as a trap crop, it is not widely adopted due to lack of seed availability. &nbsp;Quinoa, however, is a grain crop that has commercial value, and some varieties have been found to induce hatch of <em>G. pallida,</em> although at a lower rate than potato or <em>S. sisymbriifolium. </em>The data obtained in this objective will be <strong>impactful </strong>as quinoa production expands in areas of Idaho that contain <em>G. pallida.</em></p><br /> <p><em>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; </em>In this objective, many new chemical nematicides have and are being continually tested to develop crop-location-specific management strategies. For example, New Mexico researchers have continued their <strong>activities </strong>and investigations into the seasonality of <em>M. incognita</em> populations in drip-irrigated, wine-grape vineyards in southern New Mexico. The <strong>outcome</strong> of this effort will be to develop a management tool tied to growing degree days to aide farmers in determining the most effective timing for chemical control applications. As climate patterns shift, such monitoring may be increasingly important for advising growers on the management of such established pathogens, especially in perennial crops such as grapes.</p><br /> <p>Nematicides offer an effective means of nematode management, and as companies develop new nematicides, it is important to investigate the effectiveness of their formulations or their application methods. Working directly with local commercial producers to evaluate new nematicides in locally relevant cropping systems aids growers in making informed management decisions. For example, in 2023, researchers in Alabama performed <strong>activities</strong> that looked at the reniform nematode populations on cotton. They evaluated the effects of combining the nematicide seed treatments COPeO (fluopyram), or BIO<sup>ST</sup> Nematicide 100 (heat killed <em>Burkholderia rinojenses</em>) or the nematicide in-furrow Velum (fluopyram) or&nbsp; AgLogic (aldicarb) with resistant cotton cultivars on nematode population levels and lint yield. As an <strong>outcome</strong> of this research, it was concluded that having resistant cotton with an application of nematicide reduced the reniform populations more than resistance alone. The lowest reniform numbers were found in the resistant plant combined with the in-furrow nematicide AgLogic treatment, providing cotton growers with hard data to inform how they manage reniform nematode on cotton (Turner et al. 2023).</p><br /> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Organic agriculture is becoming increasingly popular and there is a critical need to study biological control of nematodes and other pests in organic cropping systems.&nbsp; In organic sweet potato production, one of the major <strong>activities</strong> has been establishing field trials across the South to determine the effect of selected winter cover crops and biological products in the suppression of nematode and insect pests. The <strong>outcomes </strong>of the initial trials were varied, but in general, the cover crop mix was associated with higher yield and lower <em>M. incognita</em> populations on sweet potatoes. Entomopathogenic nematodes (EPNs) can control insect pests, including the sweet potato weevil. <strong>Activities </strong>on EPN in Hawaii showed that EPNs could control the sweet potato weevil in the lab. In field tests, the EPN were unable to sufficiently abate damage when there was a high sweet potato weevil disease pressure. Many EPN application methods leave EPNs exposed to UV radiation and desiccating conditions but researchers in Hawaii are developing living bombs to address these limitations. EPNs were also being evaluated in corn production systems in five fields in western Nebraska for control of corn rootworm. One of the key <strong>outcomes </strong>of the Nebraska research has been data showing a low recovery of the commercial EPN product after application in corn.</p><br /> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; Changes that occur to soil biophysicochemical conditions due to agricultural practices (application of chemicals, biologicals, etc) can also influence soil health, nematode-host interactions, and the management decisions at many levels. MSU researchers have applied the soil food web model and shown that there are variable soil health outcomes in response to soil amendments and cover crop treatments (Habteweld et al. 2020;&nbsp; Habteweld et al. 2017;&nbsp; Habteweld et al. 2022;&nbsp; Melakeberhan et al. 2021;&nbsp; Melakeberhan et al. 2018). Two of the <strong>outcomes</strong> from MSU research have been a novel fertilizer use efficiency (FUE) and an integrated productivity efficiency (IPE) model that identify if soil health outcomes are sustainable and if not, what additional measures are needed to make it sustainable. The FUE and IPE models, the only ones of their kind, provide scientists and growers with integrated decision-making tools to develop and apply sustainable soil health management strategies.</p><br /> <p>&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; <strong>Final Outcomes- Researchers have harnessed biotechnology for nematode control by employing 'omics' technologies, while investigations into nematode-cropping systems underscore innovative management approaches. The continual testing of new chemical nematicides, exploration of biological products, and understanding of soil biophysicochemical conditions emphasize a comprehensive strategy toward sustainable nematode management across various agricultural systems.</strong></p><br /> <p>References cited</p><br /> <p>Anderson, S. D., and Gleason, C. A. 2023. A molecular beacon real-time polymerase chain reaction assay for the identification of <em>M. chitwoodi, M. fallax</em>, and <em>M. minor</em>. Frontiers in Plant Science 14.</p><br /> <p>Baker, H. V., Ibarra Caballero, J. R., Gleason, C., Jahn, C. E., Hesse, C. N., Stewart, J. E., and Zasada, I. A. 2023. NemaTaxa: A new taxonomic database for analysis of nematode community data. Phytobiomes Journal 7:385-391.</p><br /> <p>Dandurand, L. M., Zasada, I. A., Wang, X., Mimee, B., De Jong, W., Novy, R., Whitworth, J., and Kuhl, J. C. 2019. Current status of potato cyst nematodes in North America. Annu Rev Phytopathol 57:117-133.</p><br /> <p>Gendron, E. M., Sevigny, J. L., Byiringiro, I., Thomas, W. K., Powers, T. O., and Porazinska, D. L. 2023. Nematode mitochondrial metagenomics: A new tool for biodiversity analysis. Mol Ecol Resour 23:975-989.</p><br /> <p>Habteweld, A., Kravchenko, A. N., Grewal, P. S., and Melakeberhan, H. 2022. A nematode community-based integrated productivity efficiency (IPE) model that identifies sustainable soil health outcomes: a case of compost application in carrot production. Soil Systems 6:35.</p><br /> <p>Habteweld, A., Brainard, D., Kravchenko, A., Grewal, P., and Melakeberhan, H. 2017. Effects of plant and animal waste-based compost amendments on the soil food web, soil properties, and yield and quality of fresh market and processing carrot cultivars. Nematology 20.</p><br /> <p>Habteweld, A., Brainard, D., Kravchencko, A., Grewal, P. S., and Melakeberhan, H. 2020. Effects of integrated application of plant-based compost and urea on soil food web, soil properties, and yield and quality of a processing carrot cultivar. J Nematol 52.</p><br /> <p>Hu, S., Franco, J., Bali, S., Chavoshi, S., Brown, C., Mojtahedi, H., Quick, R., Cimrhakl, L., Ingham, R., Gleason, C., and Sathuvalli, V. 2023. Diagnostic molecular markers for identification of different races and a pathotype of Columbia Root Knot Nematode. PhytoFrontiers&trade; 3:199-205.</p><br /> <p>Kaloshian, I., and Teixeira, M. 2019. Advances in plant-nematode interactions with emphasis on the notorious nematode genus <em>Meloidogyne</em>. Phytopathology 109:1988-1996.</p><br /> <p>Lartey, I., Kravchenko, A., Marsh, T., and Melakeberhan, H. 2021. Occurrence of <em>Meloidogyne hapla </em>relative to nematode abundance and soil food web structure in soil groups of selected Michigan vegetable production fields. Nematology 23:1011-1022.</p><br /> <p>Lartey, I., Kravchenko, A., Bonito, G., and Melakeberhan, H. 2022. Parasitic variability of <em>Meloidogyne hapla </em>relative to soil groups and soil health conditions. Nematology 24:983-992.</p><br /> <p>Lonardi, S., Mu&ntilde;oz-Amatria&iacute;n, M., Liang, Q., Shu, S., Wanamaker, S. I., Lo, S., Tanskanen, J., Schulman, A. H., Zhu, T., Luo, M.-C., Alhakami, H., Ounit, R., Hasan, A. M., Verdier, J., Roberts, P. A., Santos, J. R. P., Ndeve, A., Doležel, J., Vr&aacute;na, J., Hokin, S. A., Farmer, A. D., Cannon, S. B., and Close, T. J. 2019. The genome of cowpea (<em>Vigna unguiculata</em> [L.] Walp.). The Plant Journal 98:767-782.</p><br /> <p>Melakeberhan, H., Bonito, G., and Kravchenko, A. N. 2021. Application of nematode community analyses-based models towards identifying sustainable soil health management outcomes: A review of the concepts. Soil Systems 5:32.</p><br /> <p>Melakeberhan, H., Maung, Z., Lee, C.-L., Poindexter, S., and Stewart, J. 2018. Soil type-driven variable effects on cover- and rotation-crops, nematodes and soil food web in sugar beet fields reveal a roadmap for developing healthy soils. European Journal of Soil Biology 85:53-63.</p><br /> <p>Ndeve, A. D., Santos, J. R. P., Matthews, W. C., Huynh, B. L., Guo, Y. N., Lo, S., Mu&ntilde;oz-Amatria&iacute;n, M., and Roberts, P. A. 2019. A novel root-knot nematode resistance QTL on chromosome Vu01 in Cowpea. G3 (Bethesda) 9:1199-1209.</p><br /> <p>Nischwitz, C., Skantar, A., Handoo, Z. A., Hult, M. N., Schmitt, M. E., and McClure, M. A. 2013. Occurrence of <em>Meloidogyne fallax</em> in North America, and molecular characterization of <em>M. fallax</em> and <em>M. minor</em> from U.S. golf course greens. Plant Dis 97:1424-1430.</p><br /> <p>Petrillo, M. D., Matthews, W. C., and Roberts, P. A. 2006. Dynamics of <em>Meloidogyne incognita</em> virulence to resistance genes Rk and Rk in Cowpea. J Nematol 38:90-96.</p><br /> <p>Phillips, M., and Blok, V. 2008. Selection for reproductive ability in <em>Globodera pallida</em> populations in relation to quantitative resistance from Solanum vernei and <em>S. tuberosum ssp. andigena</em> CPC2802. Plant pathology 57:573-580.</p><br /> <p>Phillips, M., and Blok, V. 2012. Biological characterisation of <em>Globodera pallida</em> from Idaho. Nematology 14:817-826.</p><br /> <p>Powers, T., Skantar, A., Harris, T., Higgins, R., Mullin, P., Hafez, S., Handoo, Z., Todd, T., and Powers, K. 2019. DNA barcoding evidence for the North American presence of alfalfa cyst nematode, <em>Heterodera medicaginis</em>. J Nematol 51:1-17.</p><br /> <p>Turner, K.A., Graham, S. H., Potnis, N., Brown, S. M., Donald, P., and Lawrence, K. S. 2023. Evaluation of <em>Meloidogyne incognita</em> and <em>Rotylenchulus reniformis</em> nematode-resistant cotton cultivars with supplemental Corteva Agriscience Nematicides. J Nematol 55:20230001.</p><br /> <p>Varypatakis, K., V&eacute;ronneau, P. Y., Thorpe, P., Cock, P. J. A., Lim, J. T., Armstrong, M. R., Janakowski, S., Sobczak, M., Hein, I., Mimee, B., Jones, J. T., and Blok, V. C. 2020. The genomic impact of selection for virulence against resistance in the potato cyst nematode, <em>Globodera pallida</em>. Genes (Basel) 11.</p><br /> <p>Whitworth, J. L., Novy, R. G., Zasada, I. A., Wang, X., Dandurand, L. M., and Kuhl, J. C. 2018. Resistance of potato breeding clones and cultivars to three Species of potato cyst nematode. Plant Dis 102:2120-2128.</p><br /> <p>Zhang, L., and Gleason, C. 2021. Transcriptome analyses of pre-parasitic and parasitic <em>Meloidogyne chitwoodi</em> Race 1 to identify putative effector genes. J Nematol 53.</p>

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Impact Statements

  1. • Biogeographic information that SFW, FUE and IPE models provide novel approaches to understanding the environment where all host-nematode interactions take place, assessing efficiency of APs in developing the right management strategy on a one-size-fits-all or location-specific basis, minimizing treatments that negatively impact the soil environment, and scaling up across ecoregions.
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