Brief Summary of Minutes of Annual Meeting

NC1197: Practical management of Nematodes on Corn, Soybeans and Other Crops of Regional Importance.

Meeting Minutes

July 22-23, 2021, Ames IA.

Meeting started at 8am, with the host Prof Greg Tylka welcoming everyone to Ames and thanking them for attending. He also thanked NCSRP for sponsoring the snacks, lunch and dinner during the meeting. Self-introductions followed.

Attendance:

Greg Tylka (ISU)

Tim Todd (KSU)

Rodrigo Borba Onofre (KSU)

Cody Hoerning (MSU)

Ed Anderson (NCSRP & ISA)

Haddish Melakeberhan (MSU)

Nate Schroeder (UIUC)

Guiping Yan (NDSU)

EB Wlezien (ISU)

Monica Pennewitt (ISU)

Ann MacGuidwin (UW)

Marty Draper (Admin)

Kaitlyn Bissonnette (MSU), Chair

Emmanuel Byamukama (SDSU), Vice-Chair/Secretary

Online: Tamra Jackson (UNL, elected incoming vice-chair), Deepak Haarith; Jefferson Barizon; Gregory Bernard ; Sita Thapa; Marisol A. Quintanilla Tornel; Amer Fayad (NIFA), Vijay Nandula (NIFA).

Updates from Vijay, K Nandula –National program leader –CPPM, USDA NIFA

Dr. Nandula gave a brief history and purpose of the CPPM – including nematode management using IPM approaches at the state, regional and national levels; mentioned three programs under CPPM, ARDP, EIP, RCP. He gave the summary of proposals received by CPPM; 75 proposals in 2020, of which 4 proposals with SCN component were submitted but none were awarded.

He also gave a brief history and purpose of the CARE funding program; that started in 2013 and in 2022, $7m has been allocated to this program. Funding for CARE originally was production oriented, but now has been expanded to other programs including IPM; deadline for next cycle is Sept 15, 2022. Purpose of the CARE program is to fund research and outreach that can lead to practices that may be readily and rapidly adapted by end users. He said CARE rate of success is 33% and he encouraged submitting proposals to this program. Dr. Nandula also mentioned the pests and beneficial species program that includes nematodes as well. The purpose of this program is to advance knowledge of invasive species. He mentioned entomopathogenic pathogens for nematode control proposal funded at UC-Riverside.

He stated that multi-state and multi-disciplinary proposals have a good chance for funding. As well as postdoc proposals and new investigator proposals -A question was asked on pre-doctoral graduate students opportunities – He said inquiries should send emails to the program leaders carlos.ortiz@usda.gov

Update from the Administrator: Dr. Marty Draper

Dr. Draper informed the group that the NC-1197 renewal proposal was well received, that Nathan and Kaitlyn did a great job working on the proposal renewal rewriting. Only three comments were made – i) there was limited collaboration with other committees in the region; ii) there was some redundancy with soybean diseases committee (NCERA-137) and iii) there was also concern how this group was going to facilitate collaborative research, not just sharing ideas which would make the committee a coordinating committee. Activities of coordinating committees are not funded.  

Nathan explained that efforts were made to collaborate with NCERA-137 but these efforts were not solidified. There also was a challenge with the timing and location of the NCERA 137 meeting in FL; also the NCERA-137 soybean group may focus on only SCN whereas our NC1197 group works on many nematode species – Dr. Draper mentioned the comments were not requirements and the committees efforts to collaborate when appropriate are appreciated. Ed Anderson mentioned that the optics of the NCERA-137 meeting in Florida in February are not viewed favorably by the commodity checkoff boards.

Dr. Draper cautioned that staying as a research and extension committee helps to draw funds from the Ag experiment station to support faculty to participate in the group’s activities. Based on the updates from the NIFA admin, Dr. Draper advised our group to think of multi-state grant proposals from these programs.

He encouraged the group to put together an impact study for this committee – the collective Experiment Stations would pay for an evaluator (Sara Delheimer) to assist with the impact assessment (https://www.mrfimpacts.org/) of the committee. He said would probably be a 3-hour exercise to evaluate impact for the end users – including for instance the SCN Coalition efforts. He stated that evaluation of the committee weighting system has changed – with “multi, multi, multi” activities being considered more important than impact.

He updated the committee on the likely infrastructure funding from Congress that could have an impact on university facilities, but there remain a lot of unknowns. Preliminary indications are that there could be some increases in funding for capacity programs and AFRI. The mark-ups from the House and Senate are not as high as proposed in the President’s budget request, but any increase is good news. He thanked Ed Anderson and other commodity boards – over 350 signatories who signed a letter asking ranking members and chair of Ag committees to support ag infrastructure funding. He explained what a budget line item is and that Congress likes AFRI because they view competition grants as a form of accountability – additional screening for where money goes. However, capacity building funding is skeptically looked at by congress.  

Vijay mentioned national reporting system that is replacing REEPORT system. They are updating the review process – it is being worked on at the moment. Dr. Draper also said that the new program would also replace AREERA capacity reporting and eventually should replace NIMSS.

A question on whether funding for rapid response to a disease outbreak on plants as it is with animals was available. Vijay responded that programs including AFRI-CARE and FFAR-ROAR can provide funding for disease outbreak response efforts.

Update from Ed Anderson – NCSRP

Ed informed the group that PA was added to the NCSRP state members and the organization has now a new logo that includes PA on the map. He reminded the group that NCSRP is very supportive of the good work our group is doing. He gave a brief description of the NCSRP funding mandates: yield enhancement, soybean productivity, and yield preservation. He stated that researchers submit many ideas that sometimes are not attractive to farmers but over time, now most proposals are aligned with the interests of the farmers. He encourages collaborative and coordinated projects, which have a chance of funding. He gave an example of a 24 collaborators project on the emerging insect issues led by Kelley Tilmon at OSU, such proposals get high chances of funding. He cautioned, however, that funding longer term projects is limited to usually 3 years. He mentioned that the SCN Coalition is partially being funded by NCSRP. He went on to explain how NCSRP program gets its funding from member states which ranges between $3-4m total a year, including operations, and that USB funds ½ of the program operations budget. He said member states contribute minimum $50K and no limit to what a state can contribute towards NCSRP.

Student presentations followed. Monica presented on “An integrated approach to enhance durability of SCN resistance for long term strategic SCN management - Phase II” and Cody Hoerning gave a presentation on pennycress as an alternative host in the double cropping relay system.

During the discussions, it was mentioned that transgenic variety development was on-going, however, background in the variety was still coming from PI88788. Hence it was not clear if this would be durable given that PI88788 has been widely used in soybean varieties already. There was a discussion whether SCN juveniles would be able to ingest the protein in the transgene variety.

State reports

Missouri (Kaitlyn Bissonnette):  They have carried out nematicide seed treatment trial, a collaborative project with 30 site years of testing across 12 states and one province in Canada. They used soybean varieties with multiple susceptibility to SCN and SDS but with PI88788 as SCN source of resistance. Nematicide seed treatments were added to the generic fungicide base (standard base) with naked seed and only generic seed treatment as checks. They found inconsistencies among treatments for the females per 5 roots data. Similarly, there was no clear yield differences among treatments most likely due to other confounding factors such as soil type. The take away from their trials was that initial SCN population level, environment, soil type and other diseases such as SDS do affect response to nematicide seed treatment.

South Dakota (Emmanuel Byamukama): An update on SCN distribution by county and the SCN soil testing results for 2020 were presented. 308 soil samples were submitted for SCN testing and 35% were positive for SCN ranging from 50 to 10,600 eggs/100 cc. They are also testing 8 nematicide seed treatments this year, 2021. They reported on the study conducted to determine the efficacy of plant extracts in controlling SCN in-vitro and also on soybean plants under greenhouse conditions. Leafy spurge, ragweed, and wormwood extracts caused J2 mortality and also reduced the number of cysts that developed under greenhouse conditions. More testing is on-going.

Kansas (Tim Todd): A presentation on alfalfa cyst nematode was given. The finding of Heterodera medicaginis is the first report of this nematode on alfalfa in Kansas. Tim mentioned that there is no yellow female stage – they start as white and turn to brown right away. He mentioned that males for this species are rare (could be a research idea). Juveniles of both SCN and alfalfa cyst nematode are almost similar but alfalfa has longer stylet. He reported the Pratylenchus survey results and how they found 10 CO1 haplotypes with weak or inconsistent database matches to P. dakotaensis described in North Dakota. He also reported having worked on nematode community on tall grass prairie. They found high diversity of nematodes with Cyatholaimidae and Dorylaimidae dominating.

As a discussion, Tim brought to the Group’s attention the need to revise the HG type system. HG types are not predictive because they cannot be repeatable.  HG type in one state will be different from same HG type in another state. There is more that is not known on the genetics of both the host and the nematode to simply group SCN as one type from another. The HG type description should include the female index values in order for HG type information to be more useful.

Rodrigo Onofre gave a quick update on the SCN prevalence increase in KS from 15% in 2010 to 35% in 2020.

Wisconsin (Ann MacGuidwin): They reported on a study to determine if P. penetrans is the only dioicous species of Pratylenchus in Wisconsin. They surveyed Pratylenchus species males in 83 fields in 42 counties. They found 84% of Pratylenchus spp. were identified as P. penetrans and 16% as new species of P. dakotaensis. They also investigated the impact of P. penetrans on soybean yield in the field. Fields were fumigated in the prior year (under potato production). They found that V2 growth stage initial population numbers impacted shoot weight and grain yield and yield components. The estimated yield loss per nematode was 0.0199% under greenhouse conditions and 0.294% under field conditions. They estimated soybean yield loss caused by P. penetrans alone to be 5% based on its prevalence in soybean fields from 2013-2016 in Wisconsin (based on 94% of the samples positive for Pratylenchus spp.; and yield loss per P. penetrans nematode estimated in the field and greenhouse studies). They also investigated if SCN prevalence has changed over the years in WI. They compared SCN prevalence between 1998 – 1999 (447 farms) and 2019 – 2020 (673 farms). They report that prevalence was 17% in 1998/1999 while it was 57% in 2020 samples.  

Deepak Haarith presented on role of alpha SNP in rhg1 against SCN to try and understand SCN resistance and why it is overcome. Overexpressing an additional LC/HC alpha snap in Wm82 was lethal. It was suggested to him to use inbred SCN populations in these experiments rather than more heterogeneous HG types for improved results.

Nebraska: Tamra Jackson mentioned that they are planning on performing SCN nematode protectant testing next year.

North Dakota (Guiping Yan): They reported on the occurrence of HG types in ND. They found no populations attacked PI #s 3, 4, and 6. HG type 0 was the most predominant followed by 7, and 2.5.7.  They also evaluated 47 soybean commercial varieties for HG types 0 and 44 varieties for HG type 2.5.7 reproduction.  For HG type 0, 13% were resistant, 19% were moderately resistant. For HG type 2.5.7, 9% of the varieties were resistant. The majority of commercial varieties evaluated were not resistant to HG type 0 and 2.5.7. They are continuing to test resistant varieties and identify novel sources of resistance. They report to have found a new species of lesion nematode, Pratylenchus dakotaensis, based on molecular and morphological tests (e.g. SEM and COX1 gene). They have developed primers that are highly specific to this species. They have evaluated the new lesion nematode species on 20 soybean varieties. None was resistant, 7 were moderately resistant, 9 were moderately susceptible, and 4 were susceptible.

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Illinois (Nate Schroeder): They performed screening of perennial species for plant-parasitic nematode resistance. They screened 27 described species that have been hybridized with Glycine max. They screened against SCN and other nematodes including M. incognita, R. reniformis, and P. penetrans. They found no accession was resistant to lesion nematode while a few were resistant to SCN. They tested efficacy of ILeVO against corn-parasitic nematodes at three locations. Corn samples were collected V5 and V8. They also performed behavioral and lethality experiments on P. penetrans in the lab.  They found that impact of fluopyram on P. penetrans is life-stage specific. The higher the dose, the more immobile the nematodes were.

Nathan has been digitizing and disseminating electron micrographs of plant-parasitic nematodes from Dr. Burt Endo’s collected 40k images of plant- and animal-parasitic nematodes – Nathan collected these materials from abandoned USDA lab and so far has scanned and digitized 15k into high resolution images and annotated over 1500. These are being organized and uploaded to IL Data Bank: https://databank.illinois.edu . He has SON capacity grants to work with Jim Baldwin on archiving the nematode historical data.

Michigan (Haddish Melakeberhan): Haddish reported on the soil health work at the MSU Agricultural nematology lab he and his team have been doing. He investigated Meloidogyne spp. adaptation and parasitic variability across different soil conditions (disturbed, maturing, structured, degraded). Maturing soils had the majority of operational taxonomic units while the degraded soils had the least. He noted that development and dissemination of information should also target scientific community and not only farmers. He also presented a fact sheet developed from his lab on cover crops and plant parasitic nematodes guide.

Iowa (Greg Tylka): Greg reported on the SCN Coalition activities. He stated that most states in mid-west and one Canadian province were participating in the coalition. He outlined planned events in 2020 that were disrupted by the pandemic and how these were switched to educational brief talks named “Let’s Talk Todes”. He said these were greatly successful, have had a lot of views. The first Tode talk had almost one million views within the first 6 weeks of publishing. He gave a report on the market research performed in 2015 and in 2020. The results from these surveys indicate there was an increase in usage of SCN management practices (growers rotating genetic SCN resistance, identifying Peking as a source of resistance, using nematodes seed treatments, growers planting SCN-resistant soybean varieties and rotating with SCN non-host crops). He said there is a national Soybean Nematode conference being planned for the week of December 12-16, 2022 in Savana Georgia, and the group is also working on developing a 6^th edition of the SCN Management Guide.

General discussion 

Marisol Quintinalla commented that Peking as a source of SCN resistance was found to have low yields after 1^st year of testing in Michigan. Therefore, it may be good for rotation but not as a replacement for PI88788.

A suggestion to incorporate some of these high quality SCN Tode Talk videos and other publications into teaching tools could be used for recruiting students.  

Business meeting followed:

Kaitlyn informed the group that minutes of the previous meeting had been e-mailed out. Ann moved to approve the minutes, Tim seconded the motion.

It was agreed that an email be sent out to remind members when to send the state reports (within the 60 days when the annual report has to be filed with the NIMSS system).

A question was raised on the representative for NE and how to recruit new members to the group. Tamra said NE does not have an official representative, but she was in the process of doing the paperwork. The problem of recruiting people could be due to limitation on the number of committees a member can participate in.

A question on whether we want to have workshops – for example impact assessment workshop – a suggestion by Marty – the funds would be provided $20k – from NIMSS to carry out this workshop. This workshop would be about three hours and a specialized analyst would be paid to assist with the impact assessment of the group’s activities. Marty would do the arrangements – all it would cost is time of the meeting.

It was mentioned that in the past there was nematode ID workshop was offered. Participants were usually students. Another past workshop was on extracting nematodes from soil across different labs – this could be held depending on who is hosting the meeting.

The idea to host a workshop alongside the SCN Coalition’s National Soybean Nematode Conference in December 2022 was proposed. APS would arrange the meeting – with Melissa as the contact local person. However, the admin advised that this would be outside the federal fiscal year. Kaitlyn tabled a motion to have an official remote meeting before Sept; then do a workshop for the group with the SCN Coalition National Soybean Nematode Conference. Nate seconded the motion. In the discussions, Haddish offered to host the group meeting in case the joint meeting with the SCN Coalition’s National Soybean Nematode Conference does not happen. Tamra mentioned that the NC-APS meeting will be in NE June 22-23, 2022. The NC1197 group could hold the meeting June 21. It was suggested that Tom could help with nematode ID workshop. Kaitlin amended motion to have the meeting before the NC-APS meeting: half day on June 20^th and half day nematode ID workshop – Tim seconded - Discussion – it was clarified that the nematode ID workshop would be plant-parasitic nematodes of economic importance in the North Central region. The motion passed unanimously.

Election of the new secretary – Ann nominated Tamra – Tamra accepted to be the new secretary.

Meeting closed at 11:52 am, July 23, 2021.

Accomplishments: Plant-parasitic nematodes (PPNs) continue to be a major constraint to crop production in the north-central region and beyond. The NC1197 multistate group is assessing strategies for the control of PPNs. Special attention is given to plant-parasitic nematodes of corn and soybean.

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

1. Evaluate interactions of plant-parasitic nematodes with germplasm of economically important plants.
2. Assess intraspecific variability in nematode virulence and pathogenicity.
3. Evaluate new commercial products and innovative strategies for the control of SCN, root-lesion and other plant-parasitic nematodes.
4. Develop innovative methods to detect and quantify plant-parasitic nematodes

Participants in Illinois, Iowa, Kansas, Minnesota, and North Dakota screened soybean lines for resistance to soybean cyst nematode. In Kansas, 220 advanced breeding soybean lines were screened against SCN resistance in 2020. 87% of the early maturing and 27% of the late maturing were rated resistant or moderately resistant to HG Type 7 SCN screening population while only 26 and 27% of the early and late maturing lines, respectively, were rated resistant or moderately resistant to SCN. They also performed alfalfa cyst nematode trial and found no differences among varieties. They performed root invasion of male and female alfalfa cyst nematode on several hosts and found hairy vetch in addition to alfalfa allowed higher number of males and cyst development. In Minnesota, they evaluated 36 private and public soybean lines against SCN HG type 7 in the greenhouse and all were resistant or moderately resistant to the HG type 7. They also evaluated 13 soybean varieties with Peking as the source of resistance and 10 were resistant or moderately resistant to HG type 2.5.7.  They are a screening Pennycress germplasm against SCN HG type 7. A longer-term study on intraspecific variability in nematode virulence and pathogenicity is still on-going. In Iowa, 207 SCN commercial resistant varieties were evaluated under naturally SCN infested fields. The majority of the varieties had PI88788 resistance while only 16 had Peking resistance. Varieties with Peking resistance had the lowest end of season SCN population densities for all the locations tested.

In Illinois, interaction of plant-parasitic nematodes with perennial Glycine spp was investigated. They found that both Meloidogyne incognita (root-knot), and Rotylenchulus reniformis (reniform nematode have both shared and unique interactions along the susceptibility continuum compared with SCN. In some cases, resistance was superior to that found in resistant soybean. No resistance was found to P. penetrans in any perennial Glycine accession.

Participants in North Dakota, Indiana, Kentucky, and Wisconsin performed plant parasitic nematode surveys. North Dakota and Indiana screened for SCN populations for HG types. In North Dakota, out of 73 SCN populations screened, HG type 0 was the most common (36%) followed by HG type 7 (27%) and 2.5.7 (19%). In Indiana, a survey to determine occurrence of HG types in the state was carried out. They report 100% of the 124 soil samples were positive for SCN. HG typing is still on-going.  In Kentucky, surveys for plant parasitic nematodes were performed in soybeans and corn. They found SCN prevalence of 75%. Other plant parasitic nematodes found were dagger nematodes (7% of the fields), 27% of the fields were infested with lance nematodes, 33% were infested with lesion nematodes, 98% were infested with spiral nematodes and 2% were infested with stunt nematodes.  In Wisconsin, 57% of the 629 farms tested in 2019-2020  survey were positive for SCN compared to 17% of the 447 farms tested during the first survey 20 years ago (1989-99). In South Dakota, 35% of the samples tested were SCN positive fields in 2020 (n=310)

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In North Dakota, two experiments to evaluate resistance levels of soybean varieties against new species of root lesion nematode (Pratylenchus dakotaensis). The combined results of all the trials indicated that seven of the cultivars were moderately resistant, nine of the cultivars and the local cultivar Barnes were moderately susceptible, and four of the cultivars were susceptible. However, none of the cultivars evaluated were classified as resistant.

In Michigan, parasitic variability (PV) for northern root knot nematode was studied with particular emphasis on how presence or absence of the nematode relates to mineral and muck soils and soil food web (SFW) conditions. This study for the first time established that Meloidogyne hapla was present in disturbed and degraded conditions in both soil groups. On-going are analyses to establish the relationship between PV and SFW and soil biophysicochemical conditions.

Participants from Iowa, Missouri, South Dakota, North Dakota, Illinois, Minnesota, Kansas, Kentucky performed nematode protectant seed treatment studies. In Missouri, multiple nematode-protectant seed treatment products were evaluated as part of multi-state trial. At present, approximately 30 site-years of data have been collected across 12 states and 1 Canadian province. In Iowa, 27 field experiments to study nematode-protectant seed treatments on soybean yields and SCN population were done. The 2020 experiments showed variable effect on yield by Aveo, Trunemco and Saltro but no significant effect on SCN reproduction factor. In Kentucky, no differences were observed between nematicide seed treatments compared to the base treatment. In Illinois, Poncho Votivo and iLeVo (fluopyram) were evaluated on corn nematodes and they found the treatments reduced lesion nematode populations during early corn growth. Total plant-parasitic nematode numbers were not affected and we observed no change in yield. In North Dakota, new nematicide Vydate was tested against stubby root nematode, the vectors of the Tobacco rattle virus in potatoes and found Vydate showed significant reduction in the virus incidence and severity. In Minnesota, 7 experimental nematicide seed treatments were evaluated for SCN management in soybeans.

Participants from North Dakota and Wisconsin participated in developing innovative methods to detect and quantify plant parasitic nematodes. A rapid and accurate PCR-based method was developed for detecting and identifying a new species of root-lesion nematode (Pratylenchus dakotaensis) recently discovered in a soybean field in North Dakota. In Wisconsin, they developed a molecular identification PCR protocol for Pratylenchus spp differentiation.

Objective 2. Determine interactions of nematodes with other pests and pathogens and the impact of nematodes on plant and soil health.

North Dakota, Minnesota, Michigan, and Wisconsin participated in this objective. A micro-plot study was conducted to evaluate the effects of Pratylenchus penetrans and Fusarium oxysporum on growth and yield of ‘Red Norland’ potato in North Dakota. Their research demonstrated the potential damage by the presence of both pathogens. In Minnesota, a simulated cold environment in growth chamber and freezer was used to study whether any life stage of SCN in pennycress roots can survive at low temperature and frozen conditions. Experiments were initiated at one field site in 2019, and another field site in 2020 to study effect of planting dates of oilseed cover crop pennycress on the SCN population densities in Corn-Pennycress/Soybean-Corn production systems. In Michigan, they are applying the SFW model to assess the effect of land use and cropping systems on soil health outcomes and using the Fertilizer Use Efficiency (FUE) model to assess the potential sustainability of the outcomes. In Wisconsin, a study to determine damage function for soybean yield loss due to Pratylenchus penetrans (Pp) was carried out. They quantified the impact of Pp to the early growth and yield of soybean in field and greenhouse conditions. They have also made the first attempt to estimate yield loss caused Prateylenchus spp in soybeans based on counts in soil samples and also greenhouse relative yield loss caused by Pp. They estimated yield loss to be 0.77% across Wisconsin in 2020.

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

Iowa, South Dakota, Illinois, Wisconsin, North Dakota, Kansas, Indiana, Missouri, and Kentucky are participating in the 2^nd SCN coalition. The 2^nd coalition is sponsored by USB, NCSRP and several private Ag industries. The goal of the 2^nd coalition is to encourage soybean growers to test their soils so they can know the SCN population in their soils and also to rotate PI88788 SCN resistance with other sources of resistance. In several participating states, testing for SCN is free for soybean producers, courtesy of the checkoff dollars from the respective states. In Kansas, information on level of resistance in commercial soybean cultivars is published annually at http://www.agronomy.k-state.edu/services/crop-performance-tests/soybean/. The results obtained from this project have been used in classroom training for crop diseases and for training of certified crop advisors. For Minnesota, the SCN research data were used in SCN extension activities at the 2021 University of Minnesota Southern Research and Outreach Center Agronomy Field Day (virtual). Also the 2020 SCN variety test data were published in "2020 Soybean Field Crop Trials Results". In Missouri, a SCN webinar series was put on by the University of Missouri and the University of Kentucky over 3, one-hour sessions covering SCN basics, genetics, and management during the 2020 winter period. In Iowa, a list of 849 soybean varieties resistant to SCN for 2020 was compiled and made available on the internet.

In Illinois, Dr. Schroeder is currently digitizing the electron micrograph collection of Dr. Burt Endo (USDA). These data comprise approximately 40,000 individual images. His team has scanned approximately 15,000 of these and annotated approximately 1,000.  Annotated images are uploaded to the open access IL Data Bank https://databank.illinois.edu/.

All states in the group have given extension talks and published extension articles recommending management practices for plant parasitic nematodes as indicated in the publication list below.

Outputs:

Thirty one peer reviewed publications, 21 Extension articles, and one book chapter published on the biology and management of PPNs.

Refereed Publications:

1. Acharya, K., Yan, G. P., and Berti, M. T. 2020. Evaluation of diverse cover crops as hosts of two populations of soybean cyst nematode, Heterodera glycines. Crop Protection 135: 105205, https://doi.org/10.1016/j.cropro.2020.105205.
2. Acharya, K., Yan, G. P., and Plaisance, A. 2021. Effects of cover crops on population reduction of soybean cyst nematode, Heterodera glycines. Plant Disease 105: 764-769, doi: 10.1094/PDIS-08-20-1778-RE.
3. Alasmary, Z., T. Todd, G.M. Hettiarachchi, T. Stefanovska, V. Pidlisnyuk, K. Roozeboom, L. Erickson, L. Davis and Zhukov, O. 2020. Effect of soil treatments and amendments on the nematode community under Miscanthus growing in a lead contaminated military site. Agronomy 10:1727; doi:10.3390/agronomy10111727.
4. Androwski, R. J., Asad N, Wood J, G., Hofer A, Locke S, Smith C. M., Rose B, and Schroeder, N. E. Mutually exclusive dendritic arbors in C. elegans neurons share a common architecture and convergent molecular cues. PLOS Genetics. 16(9):e1009029
5. Bali, S., Hu, S., Vining, K., Brown, C., Majtahedi, H., Zhang, L., Gleason, C. and Sathuvalli, V. (2021) Nematode Genome Announcement: Draft genome of Meloidogyne chitwoodi, an economically important pest of potato in the Pacific Northwest. Molecular Plant-Microbe Interactions doi.org/10.1094/MPMI-12-20-0337-A
6. Bali, S., Zhang, L., Franco, J and Gleason, C. (2021) Biotechnological advances with applicability in potatoes for resistance against root-knot nematodes. Current Opinion in Biotechnology 70, 226-233
7. Bali, S., Zhang, L., Franco, J and Gleason, C. (2021) Biotechnological advances with applicability in potatoes for resistance against root-knot nematodes. Current Opinion in Biotechnology 70, 226-233
8. Bali,S., Hu, S., Vining, K., Brown, C., Majtahedi, H., Zhang, L., Gleason, C. and Sathuvalli, V. (2021) Nematode Genome Announcement: Draft genome of Meloidogyne chitwoodi, an economically important pest of potato in the Pacific Northwest. Molecular Plant-Microbe Interactionsorg/10.1094/MPMI-12-20-0337-A
9. Chowdhury, I. A. and Yan, G. P. Development of real-time and conventional PCR assays for identifying a newly named species of root-lesion nematode (Pratylenchus dakotaensis) on soybean. International Journal of Molecular Sciences 22: 5872, https://doi.org/10.3390/ijms22115872.
10. Haarith D., Kim D. G., Chen S., and Bushley K. E. 2021. Growth chamber and greenhouse screening of promising in vitro fungal biological control candidates for the soybean cyst nematode (Heterodera glycines). Biological Control 160:104635. doi.org/10.1016/j.biocontrol.2021.104635.
11. Habteweld, A., Brainard, D. Kravchenko, A. Parwinder, P.S. and Melakeberhan, H. (2020). Characterizing nematode communities in carrot fields and their bioindicator role for soil health. Nematropica 50: 201-210.
12. Habteweld, A., Brainard, D. Kravchenko, A. Parwinder, 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. Journal of Nematology DOI: 10.21307/jofnem-2020-11.
13. Han J, Schroeder NE, and N Kleczewski. 2021. A survey of plant-parasitic nematodes in Illinois corn fields, 2018 and 2020. Plant Health Progress. Accepted.
14. Handoo, Z. A., Yan, G. P., Kantor, M. R., Huang, D., Chowdhury, I. A., Plaisance, A., Bauchan, G. R., and Mowery, J. D. 2021. Morphological and molecular characterization of Pratylenchus dakotiensis sp. (Nematoda: Pratylenchidae), a new root-lesion nematode species on soybean in North Dakota, USA. Plants 10: 168, https://doi.org/10.3390/plants10010168.
15. Harbach, C.J., E.B. Wlezien, and G.L. Tylka. 2021. A mechanistic approach to assessing the potential for cover crops to serve as trap crops for the soybean cyst nematode. Plant Disease 105:1136-1142. https://doi.org/10.1094/PDIS-05-20-0964-RE
16. KC, A., Yan, G. P., Acharya, K., Plaisance, A., and Khan, M. F. R. 2021. Occurrence of plant-parasitic nematodes in sugarbeet fields of North Dakota and Minnesota. Crop Protection 142: 105503, https://doi.org/10.1016/j.cropro.2020.105503.
17. Lartey, I., A. Kravchenko, T. Marsh, and H. Melakeberhan (2021). Meloidogyne hapla occurrence relative to nematode trophic group abundance and soil food web conditions in soils and regions of selected Michigan vegetable production fields. Nematology 23: https://DOI.org/10.1163/15685411-bja10091
18. Legner, C.M., G.L. Tylka, and S. Pandey. 2021. Robotic agricultural instrument for automated extraction of nematode cysts and eggs from soil to improve integrated pest management. Scientific Reports 11:3212. https://doi.org/10.1038/s41598-021-82261-w.
19. Mao, L., Liu, Y. J., Zhang, J. J., Okerblad, J., Chen, S. Y., and Johnson, N. C. 2021. Soil biota suppress maize growth and influence root traits under continuous monoculture.  Plant and Soil 461:441-455. doi.org/10.1007/s11104-021-04848-6.
20. Melakeberhan, H., G. Bonito, A.N. Kravchenko (2021). Application of nematode community analyses-based models towards identifying sustainable soil health management outcomes: A review of the concepts. Soil Systems 5, 32. https://doi.org/10.3390/soilsystems5020032
21. Melakeberhan, H., Z. Maung, L. Lartey, S. Yildiz, J. Gronseth, J. Qi, G.N. Karuku, J.W., Kimenju, C. Kwoseh, and T. Adjei-Gyapong (2021). Nematode community-based soil food web analysis of Ferralsol, Lithosol and Nitosol soil groups in Ghana, Kenya and Malawi reveals distinct soil health degradations. Diversity 13: 101. https://doi.org/10.3390/d13030101
22. Saikai, K., and MacGuidwin, A. Difference in lesion formation by male and female Pratylenchus penetrans.  Journal of Nematology 52:1-9. DOI: https://doi.org/10.21307/jofnem-2020-090
23. Saikai, K., and MacGuidwin, A. 2020. Intraspecific variation in phenotypic and phylogenetic features among Pratylenchus penetrans isolates from Wisconsin, USA. Journal of Nematology 52:1-17. :https://doi.org/10.21307/jofnem-2020-102
24. Shi, A. N., Gepts, P., Song, Q. J., Xiong, H. Z., Michaels, T. E., and Chen, S. Y. 2021. Genome-wide association study and genomic prediction for soybean cyst nematode resistance in USDA common bean (Phaseolus vulgaris) core collection.  Frontiers in Plant Science 12:624156. doi: 10.3389/fpls.2021.624156.
25. Subbotin, S. A., Yan, G. P., Kantor, M., and Handoo, Z. 2021. On the molecular identity of Paratylenchus nanus Cobb, 1923 (Nematoda: Tylenchida). Journal of Nematology 52: 1-7, DOI: https://doi.org/10.21307/jofnem-2020-127.
26. Sun, M., Chen, S., and Kurle, J. 2021. Interactive effects of soybean cyst nematode, arbuscular-mycorrhizal fungi, and soil pH on chlorophyll content and plant growth of soybean. Phytobiomes Journal. 10.1094/PBIOMES-03-21-0024-R.
27. Thuo, A. K., Karuku, G. N., Kimenju, J. W., Kariuku, G. M., Wendot, P. K. and Melakeberhan, H. (2020). Seasonal variation of nematode assemblage and diversity on selected soil groups in Kenya: Vertisols, Cambisols and Arenosols. Tropical and Subtropical Agroecosystems 23 (2):
28. Thuo, A. K., Karuku, G. N., Kimenju, J. W., Kariuku, G. M., Wendot, P. K. and Melakeberhan, H. (2020). Factors influencing the relationship between nematode communities and edaphic factors on selected soil groups in Kenya: Vertisols, Cambisols and Arenosols. Tropical and Subtropical Agroecosystems 23(2):
29. Tylka, G.L. and C.C. Marett. 2021. Known distribution of the soybean cyst nematode, Heterodera glycines, in the United States and Canada in 2020. Plant Health Progress 22:72-74. doi.org/10.1094/PHP-10-20-0094-BR.
30. Upadhaya, A., Yan, G. P., Secor, G., and Robinson, A. 2020. Effects of co-inoculation with Pratylenchus penetrans and Fusarium oxysporum on growth and yield of potato cultivar Red Norland. American Journal of Potato Research 97: 246-255. https://doi.org/10.1007/s12230-020-09770-8.
31. Vieira, P., Peetz, A., Mimee, B., Saikai, K., Mollov, D., MacGuidwin, A., Zasada, I., and Nemchinov, L. G. 2020. Prevalence of the root lesion nematode virus (RLNV1) in populations of Pratylenchus penetrans from North America.  Journal of Nematology 52:1-10.

Book chapter:

1. Inglis, D. A., Riga, E., and Yan, G. P. 2021. Diseases caused by nematodes, Pages 61-66 in Compendium of Pea Diseases and Pests, third edition, APS Press, St. Paul, MN, U.S.A.

Extension publications

1. Berti, M. and Yan, G. P. Reducing soybean cyst nematode with brown mustard and winter camelina. North Dakota Soybean Council 2020 Research Report.
2. Bissonnette, K.M. Missouri Soybean Disease Guide. 2^nd Missouri Soybean Merchandizing Council. Winter 2021.
3. Bissonnette, K.M., Tenuta, A., and Faske, T. Soybean cyst nematode. Crop Protection Network. April 2021
4. Byamukama, E. and Strunk, C. 2019. Consider SCN sampling this spring. SDSU Extension Newsletter published May 2021.
5. Byamukama, E., and Strunk, C. 2020. Fall is a good time to test your soil for SCN. SDSU Extension Newsletter published August 2020.
6. Byamukama, E., Strunk, C., and Tande, E. 2020. Soybean cyst nematode in South Dakota: History, biology and management. Factsheet, SDSU Extension.
7. Chen, S. Strategies for managing the changing HG Types of the soybean cyst nematode.  University of Minnesota Southern Research and Outreach Center Agronomy Tour, June 22, 2021. (Virtual
8. Evin, B., Frost, K., Kinkel, L., MacGuidwin, A., Knuteson, D., Gevens, A, Larkin, B. Disease Suppressive Soils https://potatosoilhealth.cfans.umn.edu/education
9. Evin, B., Frost, K., Robinson, A., Pasche, J., Knuteson, D., Gevens, A., MacGuidwin, A., Hao, J. A Brief Overview of Soil-borne Pathogens & Pests in Potato Production Systems  https://potatosoilhealth.cfans.umn.edu/education 
10. Frost, K., Evin, B., Marks, M., MacGuidwin, A., Knuteson, D. Biofumigation:Is it a viable alternative?  https://potatosoilhealth.cfans.umn.edu/education
11. Gleason, C., MacGuidwin, A., and Knuteson, D. Nematodes for Soil Health  https://potatosoilhealth.cfans.umn.edu/education.
12. Markell, S., Yan, G. P., and Nelson, B. 2020. Soybean cyst nematode distribution in North Dakota. North Dakota State University Cooperative Extension Service Publication - Crop and Pest Report. Issue 4: Pp 8-11.
13. Melakeberhan, H. and S. Kekaire (2021). Managing Nematodes, Cover Crops, and Soil Health in Diverse Cropping Systems: MSUE Extension Bulletin (E3457). https://www.canr.msu.edu/resources/managing-nematodes-cover-crops-and-soil-health-in-diverse-cropping-systems
14. Tylka, G. 2020. Fall is a great time to sample fields for SCN - especially in 2020. Iowa State University Integrated Crop Management News (7 October 2020).
15. Tylka, G. 2020. SCN-resistant soybean varieties for Iowa - by the numbers. Iowa State University Integrated Crop Management News (23 November 2020).
16. Tylka, G. 2020. Soybean varieties with SCN resistance other than PI 88788. Iowa State University Integrated Crop Management News (7 December 2020).
17. Tylka, G. 2021. ISU SCN-resistant Soybean Variety Trial Program results for 2020 (11 January 2021).
18. Tylka, G. 2021. Sampling corn fields to assess potential for yield loss from plant-parasitic nematodes. Iowa State University Integrated Crop Management News (8 June 2021).
19. Tylka, G. 2021. SCN in Iowa: a serious problem that warrants renewed attention. Iowa State University Integrated Crop Management News (11 June 2021).
20. Tylka, G.L. and M. P. Mullaney. 2020. Soybean cyst nematode-resistant soybeans for Iowa. Iowa State University Extension Publication PM 1649, 26 pp. https://lib.dr.iastate.edu/extension_pubs/100
21. Tylka, G.L., G.D. Gebhart, C.C. Marett, and M.P. Mullaney. 2020. Evaluation of soybean varieties resistant to soybean cyst nematode in Iowa – 2020. Iowa State University Extension, publication. IPM-52, 24 pp. https://lib.dr.iastate.edu/extension_pubs/99.
22. Yan, G. P., Neupane, K., and Plaisance, A. Screening cover crops for managing the root-lesion nematode, Pratylenchus penetrans, 2020 Research Reports. Pages 131-143, Minnesota Area II Potato Research and Promotion Council and Northern Plains Potato Growers Association.