Annual/Termination Reports:

[09/15/2025]

Report Information

Participants

Creamer, Rebecca (creamer@nmsu.edu) - New Mexico State University, Entomology,
Plant Pathology and Weed Science
Cynthia Ocamb (Cynthia.ocamb@oregonstate.edu) Oregon State University
Camille Wagstaff (Camille.wagstaff@wsu.edu) Washington State University
Jinlong Han (jinlong.han@colostate.edu) Colorado State University
Silvia Rondon (silvia.rondon@oregonstate.edu) Oregon State University
ML Robinson (robinsonml@unr.edu) University of Nevada
Marysia Morawska (morawskam@unr.edu) University of Nevada
Aaron Appleby(aaron.appleby@wsu.edu) Washington State University
Erika Kay (erickarkay@gmail.com) University of Nevada
Matt Baur (mebaur@ucanr.edu) University of California
Jacob MacWilliams (jacob.macwilliams@colostate.edu) Colorado State University
Emma Tribble University of California
Nahele Bailey (nahele@biofiberindustries.com) BioFiber Industries

Brief Summary of Minutes

2025 WERA1056 – Hemp Pest Management and Production in the western US

 

Zoom Meeting

Annual Meeting Date:  08/13/2025

 

Report Date 09/18/2025

 

Participants at Annual Meeting:

Creamer, Rebecca (creamer@nmsu.edu) - New Mexico State University, Entomology,

Plant Pathology and Weed Science

Cynthia Ocamb (Cynthia.ocamb@oregonstate.edu) Oregon State University

Camille Wagstaff (Camille.wagstaff@wsu.edu) Washington State University

Jinlong Han (jinlong.han@colostate.edu) Colorado State University

Silvia Rondon (silvia.rondon@oregonstate.edu) Oregon State University

ML Robinson (robinsonml@unr.edu) University of Nevada

Marysia Morawska (morawskam@unr.edu) University of Nevada

Aaron Appleby(aaron.appleby@wsu.edu) Washington State University

Erika Kay (erickarkay@gmail.com) University of Nevada

Matt Baur (mebaur@ucanr.edu) University of California

Jacob MacWilliams (jacob.macwilliams@colostate.edu) Colorado State University

Emma Tribble University of California

Nahele Bailey (nahele@biofiberindustries.com)  BioFiber Industries

 

 

Summary of Meeting Minutes:

 

      Rebecca Creamer, WERA1056 Secretary, explained a bit about the group and its goals, Introductions were made, and the agenda was discussed. 

 

Rebecca Creamer presented Hemp IPM in New Mexico. She highlighted the diseases and insects and their management, and discussed several years of hemp trials in three areas of the state. She talked about curly top virus as it related  to curly top virusand the leafhopper preferences for different types of hemp.

 

Silvia Rondon, Oregon State University presented "Research leading to developing an Integrated Pest Management Strategic Plan in Oregon"

 

This presentation provided a recap of the history of Hemp, Cannabis sativa L., in the USA and more especially in Oregon, while highlighting research at Oregon State University with a focus on Integrated Pest Management. In Oregon, Hemp was listed among the top 20 Oregon crop commodities for the first time in 2024. According to the 2023 ODA Hemp Data, thirty counties in Oregon had 162 hemp farms. Jackson County led in hemp production, followed by Morrow and Crook Counties. Since 2018, when it was re-legalized in the USA for Hemp production for specific uses, university and private consultants have started to study agronomics, breeding, pest management, and all production aspects of the crop. Oregon is the leading producer of flowers, followed by California and Kentucky, and its economic value increased from $64 million to $113 million from 2022 to 2023 despite the reduction in Hemp acreage. In the pest management arena, programs like the Irrigated Agricultural Entomology Rondon Program started a comprehensive hemp program that included indoor and outdoor productions, with experiments ranging from biopesticide testing, pest-crop interactions focusing on pests that were initially identified as key in the industry, including Hemp russet mite Aculops cannabicola Farkas, Cannabis aphid Phorodon cannabis Passerini, wireworms, several species of leaf hoppers, and Lepidopterans like corn earworm Helicoverpa zea Boddie. Of all pests, two remained important to the industry in Oregon, the leafhopper Circulifer tenellus Baker and H. zea. Circulifer tenellus is a vector of a detrimental plant disease, the beet curly top virus (BCTV), found in Hemp and other critical economic crops, while H. zea feeds directly on hemp flowers, reducing yield. As research continues, the Oregon IPM Center is leading the effort to develop an Integrated Pest Management Strategic Plan for the crop. This ‘living’ document will summarize the needs of all parties involved in Hemp production, marketing, extension, and outreach, and private consultants to be able to serve as a place where priorities can be identified so that researchers and educators can focus their programming.

 

Cynthia Ocamb, Oregon State University presented “Phytoplasma, spiroplasma, and beet curly top in hemp in the Pacific Northwest”

 

Hemp (Cannabis sativa L.) is an emerging crop in the Pacific Northwest, primarily produced for CBD extraction and smokable flower buds.  Disease pressure faced by hemp producers in Oregon and Washington is not well understood, so disease surveys were conducted at growing sites across Oregon and in the Yakima Valley of central Washington in 2021 and 2022.  Forty-three and 37 hemp sites were surveyed for diseases in 2021 and 2022, respectively.  At each location, two 100-plant transects were examined shortly after transplanting as well as during mid- and late-season and disease symptoms were recorded for each plant.  Symptomatic plant tissue samples were collected so as to represent symptoms detected in each field on each survey date and samples were returned to the laboratory for diagnosis by PCR testing.  Beet curly top virus (BCTV) was confirmed by PCR in 50% OR and 91% WA sites in 2021; 62% OR and 100% WA sites contained plant samples positive for BCTV in 2022.  Phytoplasma (Beet Leafhopper-transmitted Virescence Agent BLTVA/FU) and Spiroplasma citri were also detected by PCR testing in a subset of diseased plant samples and often occurred at sites where plants positive for BCTV were also found.  The phytoplasma, S. citri, and BCTV were detected in both outdoor and indoor production sites; co-infections with BCTV and phytoplasma or S. citri were not unusual, while all three pathogens sometimes co-occurred in the same plant.  Symptoms attributed to BCTV, phytoplasma, and spiroplasma were variable in hemp and ranged from nearly asymptomatic to grossly deformed hemp plants.  Additional research needs for hemp include cataloging symptomology of infections in hemp caused by these pathogens, including information by pathogen strain and host genetics.

 

Camille Wagstaff, Washington State University, presented her research “The Fight for Your Fiber: Vectors, Viruses, and IPM in the Columbia Basin”

 

Industrial hemp (Cannabis sativa) production in Washington State faces emerging challenges from insect-vectored pathogens. This research focuses on the beet leafhopper (Circulifer tenellus), the primary vector of Beet curly top virus (BCTV). Using yellow sticky traps, beet leafhoppers were collected for pathogen screening alongside hemp leaf tissue samples. These surveys resulted in two first reports for WA: (1) BCTV, Citrus yellow vein-associated virus, and Hop latent viroid in industrial hemp, and (2) Candidatus Phytoplasma trifolii and Spiroplasma citri in cannabis.

Gut content analysis revealed seasonal host plants, including mustards in spring and Russian thistle and kochia throughout summer. Detection of tree species suggests potential alternative pathogen reservoirs that warrant further study. Leafhopper monitoring supports precision pesticide use and reduces unnecessary sprays, with results integrated into Washington State University’s Decision Aid System for grower decision-making.

Greenhouse experiments were initiated to evaluate BCTV symptom expression in two hemp chemovars, OTX and Kompolti. Infected plants were shorter than controls, with distinct symptom profiles: OTX developed smaller, curled leaves with greater cumulative mass, while Kompolti produced fewer, wavier leaves with reduced mass. Ongoing work will quantify viral load, examine host–virus gene expression, and assess fiber tensile strength in infected stems.

These efforts provide critical insight into vector–virus–host interactions and lay the groundwork for integrated pest management strategies that enhance sustainability and profitability of hemp production in the Columbia Basin.

 

Jinlong Han in cooperation with Punya Nachappa Colorado State University presented "Biology and management of emerging diseases in hemp."

 

Surveys across five western states confirmed beet curly top virus (BCTV) as a major viral pathogen in hemp fields. Four strains - BCTV-CO, BCTV-Wor, BCTV-PeYD, and BCTV-PeCT - were identified, with BCTV-CO and BCTV-Wor being most prevalent. Phylogenetic, recombination, and nucleotide diversity analyses revealed multiple recombination events and genetic exchange hotspots in the C1-C3 genes and intergenic region, highlighting the key role of recombination in shaping viral genomic variability. BCTV infection reduced cannabinoid levels in a genotype-dependent manner, and seed transmission was detected at low rates in seedlings. In addition, hemp proved unsuitable for long-term beet leafhopper survival. Effective management should emphasize the use of certified virus-free seeds alongside established practices to limit virus introduction and spread.

 

Marysia Morawska, University of Nevada, Reno “Hemp production in Nevada and the western US”

 

On behalf of Nevada, the update provided outlined information pertaining to the hemp market starting since 2018. Numbers regarding license holders was provided, as well as an analysis of the legal cannabis market as a whole. Proposed and submitted federal and state regulations were reviewed and discussed. Current needs and demands from the hemp market were shared, including information about patterns for success in hemp business practices. An update on current hemp businesses, hemp industry needs, and future hemp industry business ventures and advancements to watch, were also covered. 

 

 

Various participants presented field perspectives from different states.

 

New Mexico – very few hemp licenses, minimal research.

 

Washington – WSU is conducting fiber hemp trials, possible use for BioFiber, research on insect vectors and pest ecology

 

Colorado – has stable hemp production, has done research on BCTV symptoms and how that related to virus/genotype

 

Oregon – slight increase in acreage in 2024, mostly growing CBD hemp, but some fiber also. BCTV is still the biggest problem in hemp. OSU lost a full time hemp position.

 

California – There are around 60 hemp growers in the state. Fresno has 19-20 growers, which is the largest production area. It is mostly CBD hemp.

 

Nevada – very few licenses, problems with moving product for processing and concerns about water resources. Potential to grow hemp indoors in controlled atmosphere to avoid water and hear problems.

 

Research questions and priorities

 

Need more pesticides registered for use in hemp. IR4 needs to hear more about the needs for the pesticides.

See https://picol.cahnrs.wsu.edu for guide.

Need to determine the host genotype response to hemp pests and pathogens

Need better multiuse genetics with varieties good for fiber and grain.

Need better understanding of the ecology of the hemp ecosystem.

 

 

The 2026 WERA 1056 meeting.

 

Project Objectives:

1. Assess the current status of hemp cultivation and management and set priorities for integrated research on hemp pest/pathogen management and cultivation in the western US.


2. Characterization of biology of hemp pathogens, insect pests, nematodes, and weeds, including identification, genetic diversity, and detection.


3. Organize research on the ecology and epidemiology of the pathogens and their insect vectors and transmission, insect movement, and the role of weed hosts in carry-over of insect and pathogens of hemp in the western US.


4. Organize research to improve management of pests, pathogens, and weeds of hemp important in the western US with an emphasis on integrated pest management approaches.


5. Organize research on hemp cultivation in the western US, including factors such as seed/clone selection, transplant difficulties, irrigation, nutrient management for specific regions, heat stress, early maturity day length issues, and excess THC levels.


6. Organize research on hemp production at and after harvest in the western US including factors such as harvest and extraction of CBD, storage conditions, equipment necessary for harvesting grain hemp, equipment needed for processing fiber hemp, and marketing essentials.


7. Provide a national platform for education on hemp, pathogen and pest ecology and management, hemp cultivation and processing, and collaboration among scientists involved in these activities, and extending research-based information to producers and other industry members.

 

Objective 1:   Accomplished through annual meeting presentations and goal setting. See above minutes.

Objective 2:  Worked toward this goal in individual research programs. See above minutes.

Objective 3: Made progress toward the goal. Paper submitted that includes many of the participants.

Objective 4: Worked toward this goal in individual research programs.

Objective 5: 

Objective 6:

Objective 7: suggestion from Matt Baur to pull together resources on hemp IPM

 

 

Impact Statement

 

Hemp has the potential to be an important crop in many states in the western U.S. Members of the WERA1056 group increased the knowledge of the pests of hemp and their management.  The impact of curly top as a major pathogen of hemp and the importance of understanding the epidemiology of its leafhopper vector was emphasized. The needs for improved genetics and pesticides registered on hemp were highlighted. These findings should help improve the management of pests of hemp in the western U.S.

Collaborative research efforts—particularly on curly top disease on hemp—strengthened multi-institutional partnerships, expanding both the scope and impact of the work. A major collaborative milestone was the publication of a joint research paper led by Punya Nachappa, which has been accepted with major revisions in the journal of Phytopathology. In addition, members such as Silvia Rondon are developing Integrated Pest Management Strategic Plans (IPMSPs) for hemp in Oregon, while the Nachappa lab launched a comprehensive website that curates current information on hemp IPM: https://www.csuhempentomology.com/extension.html. Collectively, these efforts have enhanced regional research capacity, supported the development of practical disease management strategies, and provided critical resources for growers—ultimately contributing to the sustainability and resilience of agricultural systems in the western U.S

 

Publications

The group will publish a collaborative paper led by Punya Nachappa, which has been accepted with major revisions in the journal of Phytopathology-

 

Jinlong Han¹, Jacob MacWilliams¹, Max Schmidtbauer¹, Raiyaa Huntress¹, Maria Paula Mejia Alonzo¹, Laine Hackenberg², Jordan Withycombe³, Tyler J. Lovato¹, Camille Wagstaff⁴, David W. Crowder⁴, Rebecca Creamer⁵, Houston Wilson⁶, Kadie Britt¹, Govinda Shrestha⁷, Kenneth Frost⁸, Hannah Rivedal⁹, Cynthia Ocamb¹⁰ and Punya Nachappa¹. Beet curly top virus genetic diversity, impact on cannabinoids, seed transmission, and vector biology in hemp, Cannabis sativa. Phytopathology (Major revisions)

Rheay, H.T., Creamer, R., VanLeeuwen, D., Brewer, C.E. 2025. Field observations: photoperiod response and yield of hemp at various latitudes throughout New Mexico. Agrosystems, Geosciences & Environment. http://dx.doi.org/10.1002/agg2.70225.

Foutz, J.J., Wagstaff, C., Cooper, W.R., Swisher Grimm, K.D., Angelella, G., Wohleb, C.H., Waters, T.D., Oeller, L., Crowder, D. 2025. Weeding them out: identifying noncrop hosts and sources of infectious beet leafhopper, Neoaliturus tenellus (Hemiptera: Cicadellidae) in the Columbia River basin. Annals of the Entomological Society of America. saaf022, https://doi.org/10.1093/aesa/saaf022

Hackenberg, L., Han, J., MacWilliams, J. Kapuscinski, M.L., Stenglein, M., Fletcher, R. Nachappa, P. 2024. Exploring the hemp virome and assessing hemp germplasm for resistance to an emerging pathogen. Phytobiomes https://doi.org/10.1094/PBIOMES-06-24-0068-R

 

 

Accomplishments

<p><strong>Project Objectives:</strong></p><br /> <ol><br /> <li><strong>Assess the current status of hemp cultivation and management and set priorities for integrated research on hemp pest/pathogen management and cultivation in the western US.</strong></li><br /> <li><strong>Characterization of biology of hemp pathogens, insect pests, nematodes, and weeds, including identification, genetic diversity, and detection. </strong></li><br /> <li><strong>Organize research on the ecology and epidemiology of the pathogens and their insect vectors and transmission, insect movement, and the role of weed hosts in carry-over of insect and pathogens of hemp in the western US.</strong></li><br /> <li><strong>Organize research to improve management of pests, pathogens, and weeds of hemp important in the western US with an emphasis on integrated pest management approaches.</strong></li><br /> <li><strong>Organize research on hemp cultivation in the western US, including factors such as seed/clone selection, transplant difficulties, irrigation, nutrient management for specific regions, heat stress, early maturity day length issues, and excess THC levels.</strong></li><br /> <li><strong>Organize research on hemp production at and after harvest in the western US including factors such as harvest and extraction of CBD, storage conditions, equipment necessary for harvesting grain hemp, equipment needed for processing fiber hemp, and marketing essentials.</strong></li><br /> <li><strong>Provide a national platform for education on hemp, pathogen and pest ecology and management, hemp cultivation and processing, and collaboration among scientists involved in these activities, and extending research-based information to producers and other industry members.</strong></li><br /> </ol><br /> <p><strong>&nbsp;</strong></p><br /> <p><strong>Objective 1:&nbsp; </strong>&nbsp;Accomplished through annual meeting presentations and goal setting. See above minutes.</p><br /> <p><strong>Objective 2:</strong>&nbsp; Worked toward this goal in individual research programs. See above minutes.</p><br /> <p><strong>Objective 3:</strong> Made progress toward the goal. Paper submitted that includes many of the participants.</p><br /> <p><strong>Objective 4:</strong> Worked toward this goal in individual research programs.</p><br /> <p><strong>Objective 5:</strong>&nbsp;</p><br /> <p><strong>Objective 6:</strong></p><br /> <p><strong>Objective 7: Worked toward this goal. See Impact Statement. Also with&nbsp;</strong>suggestion from Matt Baur to pull together resources on hemp IPM, began a strategic plan for hemp in the western USA.</p><br /> <p>&nbsp;</p>

Publications

<p><strong>Publications</strong></p><br /> <p>The group will publish a collaborative paper led by Punya Nachappa, which has been accepted with major revisions in the journal of Phytopathology-</p><br /> <p>&nbsp;</p><br /> <p>Jinlong Han¹, Jacob MacWilliams¹, Max Schmidtbauer¹, Raiyaa Huntress¹, Maria Paula Mejia Alonzo¹, Laine Hackenberg², Jordan Withycombe³, Tyler J. Lovato¹, Camille Wagstaff⁴, David W. Crowder⁴, Rebecca Creamer⁵, Houston Wilson⁶, Kadie Britt¹, Govinda Shrestha⁷, Kenneth Frost⁸, Hannah Rivedal⁹, Cynthia Ocamb¹⁰ and Punya Nachappa¹. Beet curly top virus genetic diversity, impact on cannabinoids, seed transmission, and vector biology in hemp, <em>Cannabis sativa. Phytopathology (Major revisions)</em></p><br /> <p>Rheay, H.T., Creamer, R., VanLeeuwen, D., Brewer, C.E. 2025. Field observations: photoperiod response and yield of hemp at various latitudes throughout New Mexico. Agrosystems, Geosciences &amp; Environment. http://dx.doi.org/10.1002/agg2.70225.</p><br /> <p>Foutz, J.J., Wagstaff, C., Cooper, W.R., Swisher Grimm, K.D., Angelella, G., Wohleb, C.H., Waters, T.D., Oeller, L., Crowder, D. 2025. Weeding them out: identifying noncrop hosts and sources of infectious beet leafhopper, <em>Neoaliturus tenellus</em> (Hemiptera: Cicadellidae) in the Columbia River basin. Annals of the Entomological Society of America. saaf022, <a href="https://doi.org/10.1093/aesa/saaf022">https://doi.org/10.1093/aesa/saaf022</a></p><br /> <p>Hackenberg, L., Han, J., MacWilliams, J. Kapuscinski, M.L., Stenglein, M., Fletcher, R. Nachappa, P. 2024. Exploring the hemp virome and assessing hemp germplasm for resistance to an emerging pathogen. Phytobiomes <a href="https://doi.org/10.1094/PBIOMES-06-24-0068-R"><strong>https://doi.org/10.1094/PBIOMES-06-24-0068-R</strong></a></p><br /> <p><strong>&nbsp;</strong></p><br /> <p>&nbsp;</p>

Impact Statements

1. Hemp has the potential to be an important crop in many states in the western U.S. Members of the WERA1056 group increased the knowledge of the pests of hemp and their management. The impact of curly top as a major pathogen of hemp and the importance of understanding the epidemiology of its leafhopper vector was emphasized. The needs for improved genetics and pesticides registered on hemp were highlighted. These findings should help improve the management of pests of hemp in the western U.S. Collaborative research efforts—particularly on curly top disease on hemp—strengthened multi-institutional partnerships, expanding both the scope and impact of the work. A major collaborative milestone was the publication of a joint research paper led by Punya Nachappa, which has been accepted with major revisions in the journal of Phytopathology. In addition, members such as Silvia Rondon are developing Integrated Pest Management Strategic Plans (IPMSPs) for hemp in Oregon, while the Nachappa lab launched a comprehensive website that curates current information on hemp IPM: https://www.csuhempentomology.com/extension.html. Collectively, these efforts have enhanced regional research capacity, supported the development of practical disease management strategies, and provided critical resources for growers—ultimately contributing to the sustainability and resilience of agricultural systems in the western U.S

Back to top