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Spring 2022 Newsletter

Masthead: WSU NWREC News & Notes

Spring 2022 Edition

Director's Message

Dr. Carol Miles

While winter weather kept us mostly inside for work, it has not slowed us down as we continue to expand our programs and projects at WSU NWREC. A primary focus these past few months has been on recruiting a new entomologist to work with horticultural crops in northwest Washington. We interviewed four excellent candidates in March and negotiations are underway to recruit the top choice for the Entomology Department and NWREC. This faculty position will have an applied research program for insect pest management in regional crops of significance, including but not limited to blueberry, raspberry, potato, vegetable seed, flower bulbs, tree fruit and greenhouse production. Additionally, similar to most faculty at NWREC, the entomologist will have teaching responsibilities. This is a great opportunity to integrate an applied research program into the classroom, to teach the next generation of farmers, industry representatives, researchers and teachers.

Another project that we have been working on at NWREC is upgrading the parking lot at the Demonstration Gardens. We added two overhead lights to improve winter use, graded and graveled the area, aligned parking spaces for more efficient coming and going, and we are adding landscaping to make the area more attractive. This work has been possible due to funding from WSU and collaboration with the WSU Master Gardeners and the Native Plant Society. A second project that we continue to work on is upgrading the seed processing and plant drying area at NWREC. We have purchased a new dryer that we are testing with the manufacturing company, and if it works well our goal is to add two more dryers in the next year. We are purchasing some new small seed cleaning equipment with the goal of providing our researchers, staff and students with equipment that meets current industry standards so research project results are relevant to current production practices. A third, major project we are working on is the renovation of our 1948 greenhouses (4800 sq ft), which has a solid structure but needs upgrades for heating, cooling and environmental controls. We have received funding from WSU to replace the two original boilers (they are the size and shape of VW vans!) with energy efficient modern units (the size of a washing machine). The renovation will procced incrementally over the next few years as we have the funds to complete each step.

Group of people standing inside a building
Governor Jay Inslee visited the new Soils Lab in the Wiley Headhouse (Phase I of the Plant Growth Facility) in March.

A highlight at NWREC this spring was a visit by Governor Jay Inslee, who wanted to learn more about our soil health and soil-biodegradable plastic mulch projects. We were pleased to host him in our new Soils Lab that is part of the Wiley Headhouse, which was funded by a Skagit County Economic Development/Public Facilities Project grant and a generous gift from Nancy Kercheval in the name of her mother Ruth Wiley. At this time we have placed on hold our plan to proceed with Phase II of this project, to construct a new Plant Growth Facility. While we have received another generous donation, the cost to build a new greenhouse has increased substantially due to supply and labor shortages so we are reassessing our approach for future plant growth and lab facilities at NWREC.

We hope the wet spring weather is not slowing you down. Our crews are out prepping fields and planting in every break we get in the weather. We look forward summer and seeing you in the fields!

Feature Focus: WSU NWREC is Buzzing for Pollinators

Woman and man holding signs in a garden.
By Dr. Lisa Wasko DeVetter (Associate Professor of Small Fruit Horticulture) and Dr. Bob Gillespie (retired entomologist)

“If the bee disappeared off the surface of the globe, then man would have only four years of life left. No more bees, no more pollination, no more plants, no more animals, no more man.”
Maurice Maeterlinck, “The Life of the Bee”, published in 1901 (often erroneously attributed to Albert Einstein)

Over 100 years later, the quote above still resonates loudly with truth. We depend on bees and they are linchpins in natural and agricultural systems. Bees as well as other insects are important pollinators that move pollen from flower to flower. While this behavior may seem inconspicuous, we depend on it to produce the bounty of foods important for farming enterprises as well as a nutritious diet. Blueberries, raspberries, apples, tomatoes, and vegetable seed crops are just a handful of examples of plant species that require insects to develop seeds and fruits.

Unfortunately, many insect species including pollinators are declining. Habitat loss, poor nutrition, climate change, pests and pathogens, as well as pesticide exposure are considered to be some of the culprits of pollinator decline. These declines are happening to both managed species, like honey bees, and natives. In order to bring attention to the importance of pollinators as well as educate the community on efforts to help them, we are spearheading a pollinator initiative at WSU NWREC with support from other members within the northwestern Washington community.

One way to help pollinators is through habitat provisioning. Well-crafted habitat for pollinators should provide floral resources (i.e., “food” for pollinators) that bloom from early spring through fall so insects have access to adequate nutrition for their healthy development. In addition, habitat provisioning means safe nesting resources are available for pollinators that dwell on trees, within brush, and in the ground. We have taken the first steps within our initiative of strategic habitat provisioning for pollinators. This was accomplished by establishing a native pollinator habitat at WSU NWREC with plants donated from the Native Plant Society. Our goal is to expand this habitat and become Bee Friendly Farming certified within a few years so we can model and educate the community on how to support pollinators through habitat provisioning.

Illustration of sign, bee flies between two roses.Another way to help pollinators is to educate the public and agricultural community on their importance. Through education, we can all be made more aware and proactive to help pollinators. The pollinator habitat will be one venue to educate the public on the importance of habitat and how to design a habitat that will benefit pollinators. Recently, we also completed educational signs that will inform visitors at WSU NWREC about pollinators. These beautiful signs were designed with the help of Andrew Mack and in beds around the NWREC main building. We encourage you to visit them, learn, and share what you learned with others.

Workshops are also excellent venues to educate. Last year Dr. Gillespie successfully led a Native Pollinator workshop with the North Cascades Institute. The workshop was done in collaboration with NWREC and will be repeated in 2022. Much of the workshop focuses on species identification, but resources and content on how to support pollinators is also made available.

Washington State University is also providing leadership on pollinator research. Dr. DeVetter has been leading research on improving pollination in blueberry systems in Washington State with an emphasis on honeybees. The Department of Entomology also has renowned researchers dedicated to the topic and is in the process of hiring a Pollinator Health specialist to be based in eastern Washington. While much of the research emphasis has been placed on honeybees due to their importance in agricultural systems, DeVetter has been expanding her program to also include native pollinators given their effectiveness and because they can contribute to improved and more resilient pollination. As information is generated through DeVetter’s research as well as others, it will be blended into our educational efforts for our pollinator initiative.

For those of you reading this article with a fear of bees and their stings, we wanted to end by noting that most bee species do not have painful stings. Therefore, what you can do to support bees and pollinators should hopefully make you “a buzz” with joy for contributing to this important effort and not increase your risk of stings!

Lunch & Learn Seminars

There are no upcoming events at this time.

Program Highlights

Berry and Potato Pathology

Two women work on a potted blueberry bush.
Dayna Loeffler and Purnima Puri inoculating blueberry flowers with spores of mummy berry pathogen.

In February 2022, we launched the first online decision support system to aid mummy berry disease management for highbush blueberries in northwestern Washington (collaborators: Mladen Cucak, Dalphy Harteveld, Tobin Peever, Lisa DeVetter, Lav Khot, and Sean Hill). This support system is freely accessible to public on the WSU AgWeatherNet portal. We monitored the development of mummies in four counties (Whatcom, Skagit, Snohomish, and Island) during February through April 2022 and provided weekly updates to blueberry growers and stakeholders through Skagit and Whatcom County Extension Offices. Dayna Loeffler setup spore traps in three counties (Whatcom, Skagit, and Snohomish) to detect mummy berry pathogen spores from air samples. Furthermore, we are actively reaching out to blueberry growers to obtain mummy berry diseased samples for isolating the pathogen and conducting further lab studies. We are also screening blueberry genotypes for resistance to mummy berry disease [collaborators: Lisa DeVetter, Claire Luby (USDA-ARS), and Fall Creek Nursery in OR].

In collaboration with USDA researchers Virginia Stockwell and Jeff DeLong, Roshani Baral (M.S. student) is working on a project that seeks to understand the relative sensitivity of Botrytis spp. isolates to different fungicide chemistries routinely used in blueberry production in the Pacific Northwest. As part of this project, Roshani and Jeff have collected blueberry tissue samples from 36 fields (Skagit and Whatcom Counties during Feb-Apr 2022) and obtained several Botrytis isolates. Additional sampling will be done from green and mature berries during the growing season. Babette Gundersen and Purnima Puri (M.S. student) are setting up field trials at NWREC to study soil and environmental factors involved in the development of silver scurf disease in potatoes.

Cider Education

A bottle of cider

In December 2021, our cider class instructor Bri Ewing Valliere left WSU to work as a Research & Strategy Consultant for a global market intelligence firm. We thank Bri for over four years of service, under her leadership the cider education program at NWREC grew stronger. We are currently collaborating with the Cider Institute of North America (CINA) and partners Brock University and Cornell University to continue to offer cider making classes at NWREC. This Spring, the course Cider & Perry Production—A Foundation is being taught online over 8 to 16 weeks. This summer the advanced class Science, Practice & Quality Assured Cider & Perry Production will be taught at NWREC with instructor Peter Mitchell, who started cider education in the U.S. at Cornell and NWREC in 2002-03. These classes fill up quickly, so if you would like to register but the class is full, we recommend asking to be added to the wait-list for the next class.

For more information, see the Cider Program events calendar and please visit the CINA website for the most up-to-date information on courses, certifications, and other CINA resources.


Man sitting in microscopy lab, turned to the camera.As we have been searching for our new Horticultural Crops Entomologist, entomology projects and questions have been addressed by Ben Diehl, research technician for the program.

This will be the final year of a research project exploring thrips as a trade barrier in Alaska-grown peonies. This is a multi-agency collaboration between USDA, State of Alaska DNR, WSU, USDA ARS, University of Alaska Fairbanks, and peony growers in Alaska. WSU final research objectives include curation of slide mounted thrips specimens in advance of their move to Alaska, completion of a Lucid key to thrips collected from Alaska-grown peonies, development of outreach materials, and planning a second year of field efficacy trials against thrips conducted at the University of Alaska Fairbanks in summer of 2022.

Ben assisted Dr. Brook Brouwer, San Juan County WSU Extension, in the collection and identification of adult wireworms from pheromone traps placed primarily in Western Washington. Pheromone baited pit-fall traps were placed in several counties during the spring/summer of 2021, targeting species belonging to the genera Agriotes and Limonius. Trap samples were sent to the NWREC Entomology laboratory for identification. This research will provide a better understanding of the distribution and seasonality of several wireworm species, many of which are considered serious agricultural pests. This summer, Ben will be working on a few blueberry and raspberry IPM projects funded by the small fruit industry groups and Washington State Commission for Pest Research grants.

Small Fruit Horticulture

Woman in hood holding a bee hive frame.The Small Fruit Horticulture (SFH) program is led by Dr. Lisa DeVetter. Our focus is to develop and evaluate alternative management systems designed to promote plant productivity, fruit quality, on-farm efficiencies, and the health of adjacent natural resources within the diverse conditions of Washington State. We work across the state with blueberry, raspberry, and strawberry growers. This translates into a lot of diverse projects that we hope benefit the industry.

Since our last program update, former student Brenda Madrid completed her M.S. research on plastic mulch. She specifically investigated approaches to enhance degradation of soil-biodegradable plastic mulches and assessed plastic mulch adoption among raspberry growers. In addition, postdoctoral researcher Maxime Eeraerts and Emma Rogers spearheaded blueberry pollination research that shed light on landscape-level effects of honeybees hive stocking density, impacts of honeybee colony placement, and the species diversity of native pollinators. Our other graduate students, May Wang and Qianwen Lu, made progress with their studies on mulching and nutrient management, respectively, and are poised to graduate in 2022. We have new faces in our program as well. Brian Maupin joined as our new Scientific Assistant and is bringing his expertise and enthusiasm to the program. Furthermore, Kayla Brouwer and Dakota McFadden joined the program as new graduate students working on blueberry pollination and hydomulching for organic systems.

Six people in coveralls standing next to berry field.In addition to research, we have been active extending information on mulching, nutrient management, machine harvesting, and postharvest management via webinars. The heat dome and flooding experienced in northwestern Washington were also significant events for our program and certainly small fruit growers. We responded by documenting damage, generating a regional response that included information on best practices moving forward after these extreme events, and have been developing research projects to address how to mitigate damage due to these environmental events that are forecasted to increase in frequency and intensity. Much of this information can be found on our website and is shared via social media (Lisa DeVetter @WSU_SmallFruits). Please note these resources so you can follow our developments and get access to information.

Soil Health

Six people stand in front of a banner.
Members of the Soil Health and Soils & Water team at the Soil Science Society of America International Conference
Woman taking selfie in a vineyard.
Recent M.S. graduate Molly McIlquham in one of the wine grape vineyards where she conducted her soil health assessment.

The Soil Health team had a productive winter and spring, keeping busy with sample and data analysis from our wide array of soil health projects in crops across the state, including potatoes, spinach seed, quinoa, wheat, wine grapes, red raspberries, hops, and pulses. We also had numerous opportunities to present our findings to stakeholders and fellow researchers, including at the Soil Science Society of America international conference. The WA State Soil Health Roadmap was also published and includes a section focused on annual cropping systems in Northwestern Washington that was led by the Soil Health and Soils & Water teams.

Field season is getting into full swing, with three Ph.D. students—Evan Domsic, Madeline Desjardins, and Kwabena Sarpong—working on several on-farm trials around the state. We are also looking forward to the second season of our Long-Term Agroecological Research & Extension (LTARE) site at NWREC.

Congratulations to Molly McIlquham who is graduating with her M.S. in Soil Science in May 2022! Molly’s thesis focused on assessing soil health indicators and management practices in Washington’s wine grape systems. She has been a valuable member of our team and won several awards during her time at NWREC, including First Place in the Science Coalition’s National Student Video Challenge. We know Molly will continue to do excellent work to promote soil health in agricultural systems.

Soils & Water

Three people standing next to lighted "UTAH" sign.
Gabe, Navdeep Singh (postdoc), and Tessa Belo (MS Student) at an the annual meeting of the Soil Science Society of America in November, 2021.
Two people stand in front of glass doors.
Gabe and MS graduate Cheyenne Sloan on her last day with the program before moving to Michigan to work as an Extension Educator.

The past year our program wrapped up a few projects that span our focal areas of soil-plant-water relationships, soil physical and hydrologic health, and soil fertility and water-nutrient interactions, though we are continuing to disseminate the results of this work through multiple avenues. For example, we presented at the Western Washington Seed Workshop on three years of work showing that vegetative biomass (and potentially seed quality) is more sensitive to moisture stress than seed yield, and that moisture stress can increase the severity of the foliar disease Stemphylium leaf spot under certain conditions. This work will continue by focusing on the timing of irrigation, rather than the timing and quantity, given the limitations farmers face with access to irrigation equipment and water. On the perennial side of NW WA agriculture, another 3-year project demonstrated that soil organic matter can substantially contribute to blueberry plant nitrogen requirements in a timely manner, but that plants are tolerant to a range of nitrogen fertilization rates, providing blueberry growers some flexibility as they adjust fertilization practices.

In addition to multiple continuing projects in crops ranging from cider apples to onions, we’re excited for several new projects, including a collaboration with Viva Farms to build capacity for producers to experiment with soil health management practices and our role in a $10 million USDA NIFA Sustainable Agricultural Systems grant that will expand upon our Soil Health Initiative Mount Vernon Long-Term Agricultural Research and Extension site and look at linkages between soil management and crop nutritional quality. We continue to work with farmers to experiment with irrigation scheduling and soil moisture management, so please don’t hesitate to reach out if you are interested in working with us.

Vegetable Horticulture

Trays of plants in a greenhouse.
Sweetpotato slips growing in the greenhouse.

Over the winter we focused on developing curing, storage and slip production methods for sweetpotatoes, using the facilities we have on hand at NWREC (see Sweetpotatoes grown at NWREC have been impacted by wireworm the past few years, similar to grower experiences in the region. And so we are focusing on testing wireworm resistant breeding lines developed by the USDA and North Carolina State University sweetpotato breeders. Last year we propagated the wireworm resistant breeding lines at NWREC and this year we are collaborating with Laurel Moulton, WSU Extension Small Farms Program in Jefferson and Clallam Counties, to carry out on-farm trials on the Olympic Peninsula. Our vegetable grafting project is focusing on training farmers to graft watermelon and evaluate the quality and productivity of grafted transplants. We will also carry out a second year of testing new cantaloupe cultivars developed by a small Japanese seed company, whose breeder is a WSU alum. It is good to know the Cougar ties are strong for the international world of vegetable crop development and testing. Our soil-biodegradable plastic mulch (BDM) project is focusing on transcribing research articles into factsheets and slide presentations so that growers and extension specialists have easy access to this new information. All of this work is being carried out by MS student Srijana Shrestha. MS in Ag students Ann Kowenstrot will be starting a new project to phenotype heirloom rhubarb cultivars in Alaska, and Julie Figgins will be evaluating popping bean breeding lines in the Columbia Basin. PhD student Alex Cornwall (Biological Science Technician, USDA Plant Introduction Center, Pullman) is carrying out genetic and phenotyping experiments to identify 65 unknown lettuce accessions in National Plant Germplasm System.

Tractor with large vertical cutter in orchard.
Hedging the cider apple research orchard at WSU Mount Vernon NWREC.

In our research cider apple orchard, MS student Aidan Kendal has completed his studies to evaluate mechanization to reduce labor needs for managing a cider apple orchard. By using a hedger, it took 1 person 1.45 hours to summer prune our medium-density orchard that has 65 different cultivars. By hedging, the trees are able to fit inside the over-the-row mechanical harvester that Seth Brawner, a new MS student in my program, will be testing this year. Additionally, our irrigation research with Dr. Gabe LaHue (Soils and Water program) continues to show that reduced irrigation can conserve water while not sacrificing fruit yield or quality.

Vegetable Seed Pathology

Two people in a field with plastic trays.
Transplanting beets.

The Vegetable Seed Pathology (VSP) program had a very productive winter season. We completed the 13th Annual Spinach Fusarium Wilt Soil Bioassay in which we screened soil from 41 fields in western Washington to quantify the risk of Fusarium wilt for spinach seed crops. We also screened 33 spinach parent lines to help seed companies understand the relative susceptibility of their spinach lines to Fusarium wilt. Results of the soil bioassay and parent line trial are used each year by spinach seed growers and seed companies to select fields in which to plant spinach seed crops. In February, members of the VSP program and Dr. LaHue’s soils program had the joy of cutting and evaluating ~20,000 onion bulbs in Pasco for bacterial rots. The bulbs were harvested in fall 2021 from field trials in the Columbia Basin as part of a USDA NIFA Specialty Crops Research Initiative project on onion bacterial diseases. In January, PhD students Alex Batson, Marilen Nampijja, and Kayla Spawton and Lindsey du Toit gave presentations on VSP research projects during the Western Washington Seed Workshop in Mount Vernon, WA. We welcomed Asbjorn Sohlholdt, MS student at Aarhus University in Denmark, who spent 2 weeks visiting the VSP program working with PhD student, Kayla Spawton, to learn about Stemphylium leaf spot of spinach, the topic of both Asbjorn’s and Kayla’s research projects. On February 16, 2022, Kayla and Lindsey attended the TX Spinach Field Day near Crystal City, where Kayla had a baby leaf spinach field trial planted with 86 cultivars.

Large group of people standing next to a field.
TX Spinach Field Day

The 2022 field season for the VSP program has started despite cold and very wet spring conditions. Onion field trials were planted in Pasco in the Columbia Basin in late March, and promptly received 4 inches of snow! Marilen Nampijja’s beet seed crop field trial on bacterial leaf spot was planted on April 15th. We are waiting for the ground to dry out enough to plant >150 carrot cultivars submitted by seed companies from around the world, to demonstrate at the 40th International Carrot Conference that will take place at the WSU Mount Vernon NWREC on August 29-30. Lindsey du Toit is chair of the committee organizing this event. An organic demonstration trial of carrot cultivars will be planted at Ralph’s Greenhouse in Skagit Co. for inclusion in the field tour during the 40th ICC.

On April 7, 2022 we welcomed the newest member of the VSP team, Eleana Nampijja, born to Ph.D. student Marilen Nampijja!

Finally, congratulations to PhD students Marilen Nampijja and Kayla Spawton, who both received awards.

  • Marilen Nampijja received the APS Foundation Raymond J. Tarleton Student Fellowship ($1,000) in January 2022.
  • Kayla Spawton received the WSU CAHNRS Everette J. and Helen G. Kreizinger Endowed Scholarship ($5,000) in April 2022.

Weed Science

Man examining strawberry plant.

After the retirement of our weed scientist in December, weed technician Brian Maupin has been responding to weed management questions. Brian has been instrumental at NWREC in carrying out IR-4 research projects to test new herbicides for crops in our region. This winter Brian was busy helping Steve Seefeldt finish up project reports and responding to quality control audits of IR-4 reports. In addition, Brian spent the winter inventorying, organizing, and cleaning up the Weed Science program equipment and areas, so they are ready for a new weed scientist when the opportunity is available to replace this position.

This past month, Brian left the Weed Science program to become the research technician with the Small Fruit Horticulture program. We are very glad that he will be continuing to work at NWREC and we will be able to continue to ask his assistance with weed management questions.

Employee and Graduate Student Highlights

New Arrivals

Graduate Students

  • Dakota McFadden, PhD Student in Small Fruit Horticulture, Biodegradable composite hydromulches for sustainable organic horticulture
  • Roshani Baral, MS Student in Berry and Potato Pathology, Botrytis management in blueberries
  • Kayla Brouwer, MS Student in Small Fruit Horticulture, Pollination of highbush blueberries
  • Purnima Puri, MS Student in Berry and Potato Pathology, Silver scurf management in potato
  • Seth Brawner, MS Student in Vegetable Horticulture, Mechanized hedging and harvest of cider apples


  • Dayna Loeffler, Research Technologist
  • Jenny Martin, Intern
  • Drew Morris, Research Assistant
  • Doug Jensen, Maintenance Mechanic III
  • Mikelyn Rochford, Administrative Assistant


Departing Staff

  • Congratulations to Steven Seefeldt on his retirement in December 2021 after many years at NWREC. We wish him all the best in his retirement!
  • Congratulations to Bri Ewing Valliere, who started her position as a Research & Strategy Consultant with the global market intelligence firm Mintel. We wish to very best to Bri in her new position!


  • Congratulations to our recent and upcoming graduates: Brenda Madrid, Aidan Kendall, May Wang, Tessa Belo, Molly McIlquham, and Srijana Shrestha.
  • Congratulations to Jeff DeLong (USDA-ARS) on his adjunct appointment at WSU NWREC.


  • Anunciado, M., L. Wadsworth, S. Ghimire, C. Miles, J. Moore, A. Wszelaki, and D. Hayes. 2021. Deterioration of soil-biodegradable mulch films during storage and its impact on specialty crop production. HortTech 31:798-809.
  • Bagnall, D.K., Morgan, C.L.S., Cope, M., Bean, G.M., Cappellazzi, S., Greub, K., Liptzin, D., Norris, C.L., Rieke, E., Tracy, P., …Griffin‐LaHue, D.,…, Honeycutt, C.W., 2022. Carbon‐sensitive pedotransfer functions for plant available water. Soil Science Society of America Journal. 1–18.
  • Batson, A.M., Fokkens, L., Rep, M., and du Toit, L.J. 2021. Putative effector genes distinguish two pathogenicity groups of Fusarium oxysporum f. sp. spinaciae. Molecular Plant-Microbe Interactions 34:141-156.
  • Batson, A., Spawton, K, Katz, R., and du Toit, L.J. 2022. Cladosporium leaf spot, caused by Cladosporium variabile, in winter high tunnel production of spinach (Spinacia oleracea) in Maine, United States. Plant Disease 106: in press 2022. PDIS-11-21-2424-PDN.R1.
  • Belo, T., du Toit, L., Waters, T., Derie, M., and LaHue, G. 2021. Effects of irrigation frequency and final irrigation timing on onion bacterial diseases in the Columbia Basin of Washington, 2020. Plant Disease Management Reports 15:V109.
  • Belo, T., LaHue, G., du Toit, L., and Waters, T. 2021. When to water: How do irrigation frequency and final irrigation timing influence onion bacterial diseases? Onion World December 2021:6-8.
  • Block, A.K., Tang, H.V., Hopkins, D., Mendoza, J., Solemslie, R.K., du Toit, L.J., and Christensen, S.A. 2021. A maize leucine-rich repeat receptor-like protein kinase mediates responses to fungal attack. Planta 254:73.
  • Brouwer, B.; B. Diehl, T. Alexander, S. Bramwell, and B. Gerdeman. 2021. Biology and Management of Wireworms in Western Washington. Washington State University Extension Publication FS364E. Washington State University.
  • DeVetter, L.W., E. Gerbrandt, B. Strik, A. Melathopoulos, J. Pscheidt, J. Weiland, I. Zasada, V. Stockwell, D. Bryla, M. Dossett, C. Mattupalli, C. Benedict, G. LaHue, D. Griffin LaHue, M. Zhu, C. Teasdale, and M. Eeraerts. 2021. The promise and pitfalls of using managed bumblebees for blueberry pollination. Growing Produce. Aug. 2021.
  • DeVetter, L.W., M. Eeraerts, and A. De la Luz. 2021. Blueberry pollination in polytunnels. Washington State University White Paper. Available at:
  • DeVetter, L.W., E. Gerbrandt, B. Strik, A. Melathaopoulos, J. Pscheidt, J. Weiland, I. Zasada, V. Stockwell, D. Bryla, M. Dossett, C. Mattupalli, C. Benedict, G. LaHue, D. Griffin LaHue, M. Zhu, C. Teasdale, J. Pond. Berry Crops and Flooding, December 2021.
  • DeVetter, L.W.*, F. Takeda, J. Chen, and W. Yang. 2021. Harvesting blueberries: A guide to machine pick blueberries for fresh market. Washington State University Extension Publication. Pp. 11. FS368E.
  • Devi, P., L. DeVetter, M. Kraft, S. Shrestha and C. Miles. 2022 Micrographic view of graft union formation between watermelon scion and squash rootstock. Front. Plant Sci., in press.
  • Devi, P., L. Tymon, A. Keinath and C. Miles. 2021. Progress in grafting watermelon to manage Verticillium wilt. Plant Pathology, 767-777.
  • du Toit, L.J., Derie, M.L., Gundersen, B., Waters, T.D., and Darner, J. 2021. Effects of late-season cultural practices on bacterial leaf blight and bulb rot in an onion bulb crop in Pasco, WA, 2020. Plant Disease Management Reports 15:V100.
  • du Toit, L.J., Derie, M.L., Gundersen, B., Waters, T.D., and Darner, J. 2021. Efficacy of bactericides for management of bacterial leaf blight and bulb rots in an onion crop in Pasco, WA, 2020. Plant Disease Management Reports 15:V107.
  • du Toit, L.J., Derie, M.L., Gundersen, B., Waters, T.D., and Darner, J. 2021. Efficacy of disinfectants applied to onion bulbs in storage for control of bacterial bulb rots, Pasco, WA, 2020-2021. Plant Disease Management Reports 15:V102.
  • du Toit, L., and Waters, T. 2021. Shank or irrigate? Evaluating methods of application of metam sodium for onion production in the Columbia Basin. Onion World, January 2021:14-21.
  • du Toit, L., and Waters, T. 2021. To disinfect or not? Can postharvest applications of disinfectants reduce bacterial bulb rots in storage? Onion World, July/August 2021:6-9.
  • Gerbrandt, E., L.W. DeVetter, B. Strik, D. Griffin LaHue, G. La Hue, M. Dossett, M. Sweeny, and V. Stockwell. 2021. Severe flooding of blueberry fields in southwestern British Columbia and northwestern Washington. Washington State University White Paper. Available at:
  • Griffin-LaHue, D. Can biosolids give a boost to cover crops in dryland, integrated grazing-crop systems? Featured Research Short-Story in the Northwest Biosolids monthly newsletter and website. September 20, 2021.
  • Griffin-LaHue, D. Impacts of biosolids on soil health: Updates from the Soil Health Institute’s project. Featured Research Short-Story in the Northwest Biosolids monthly newsletter and website. April 20, 2021.
  • Griffin-LaHue, D., S. Ghimire, Y. Yu, E. Scheenstra, C. Miles, and M. Flury. 2022. In-field degradation of soil-biodegradable plastic mulch films in a Mediterranean climate. Science of the Total Environment. 806(1):150238.
  • Gyawali, S., Bhattarai, G., Shi, A., Kik, C., and du Toit, L.J. 2021. Genetic diversity, structure, and selective sweeps in Spinacia turkestanica associated with the domestication of cultivated spinach. Frontiers in Genetics 12:740437.
  • Gyawali, S., Derie, M.L., Gatch, E.W., Sharma-Poudyal, D., and du Toit, L.J. 2021. Lessons from 10 years of stakeholder adoption of a soil bioassay for spinach Fusarium wilt. Plant Pathology 70:778-792.
  • Hills, K., C. Benedict (Eds.), M. Blua, D. Collins, T. DuPont, D. Griffin LaHue, G. Hoheisel, A. Jensen, M. Keller, R. Koenig, C. Kruger, G. LaHue, A. McGuire, M. Moyer. Washington Soil Health Initiative Roadmap, November 2021.
  • Hulse-Kemp, A.M., Bostan, H., Chen, S., Ashrafi, H., Stoffel, K., Sanseverino, W., Li, L., Cheng, S., Schatz, M.C., Garvin, T., du Toit, L.J., Tseng, E., Chin, J., Iorizzo, M., and van Deynze, A. 2021. An anchored chromosome-scale genome assembly of spinach (Spinacia oleracea) improves annotation and reveals extensive gene rearrangements in euasterids. Plant Genome 14:e20101.
  • Kendall, A., T.R. Alexander, G.T. LaHue, and C.A. Miles. 2022. Summer mechanical hedging to prune eight cider apple cultivars. HortTechnology, in press.
  • Kendall A., Miles C., Alexander T., Scheenstra E., and G.T. LaHue. 2022. Reduced irrigation during orchard establishment conserves water and maintains yield for three cider apple (Malus domestica Borkh.) cultivars. HortScience 57:118-125.
  • Kubalek, R. D. Granatstein, D. Collins, and C. Miles. 2022. Review of tarping and a case study on small-scale organic farms. HortTechnology in press.
  • LaHue G.T. and B.A. Linquist. 2021. The contribution of percolation to water balances in water-seeded rice systems. Agric. Water Manag. 243:106445.
  • Liu, B., Stein, L., Cochran, K., du Toit, L.J., and Correll, J.C. 2021. Three new fungal leaf spot diseases of spinach and the evaluation of fungicide efficacy for disease management. Plant Disease 105:316-323.
  • Lu, Q., C. Miles, and L.W. DeVetter. 2021. Assessing sap analysis as a potential tool for evaluating raspberry leaf tissue nitrogen concentration. WSU Whatcom Ag. Monthly. Volume 10 Issue 9. Accessible at:
  • Lu, Q., C.A. Miles, H. Tao, and L.W. DeVetter. 2022. Reduced nitrogen fertilizer rates maintained raspberry growth in an established field. Agronomy 12(3):672.
  • MacKay, H., and du Toit, L. 2021. Progress report. Stop the Rot: A national collaboration to research, combat bacterial diseases of onion. Onion World, May/June 2021:12-14.Mattupalli, C., Shiller, J. B., Proano, F., Watkins, T., Hansen, K., Garzon, C. A., Marek, S. M., and Young, C. A. 2022. Genetic diversity of Phymatotrichopsis omnivora based on mating type and microsatellite markers reveal heterothallic mating system. Plant Disease
  • Mattupalli, C. 2022. Weekly mummy berry updates (2/14/2022-4/3/2022). Accessible at:
  • Mattupalli, C. Charkowski, A. O., Ingram, J. T., and Filiatrault, M. J. 2022. Rethinking seed potato certification: Moving toward a grower-focused system. Spudman 60(1):25-28.
  • Mattupalli, C., Charkowski, A. O., Ingram, J. T., Filiatrault, M., Sklarczyk, D., Ebe, G. D. 2022. COVID-19 tech provides lessons for seed potato certification improvements. Spudman 60(3):14-19.
  • McDonald, M.R., Collins, B., du Toit, L.J., and Adusei-Fosu, K. 2021. Soil amendments and fumigation for the management of Fusarium wilt of bunching spinach in Ontario, Canada. Crop Protection 145:105646.
  • Nampijja, M., Crane, S., du Toit, L., and Ocamb, C. 2021. Beet – Bacterial leaf spot. In: 2021 Pacific Northwest Pacific Northwest Disease Management Handbook, J.W. Pscheidt and C.M. Ocamb, editors. A Pacific Northwest Extension Publication, Oregon State University, Washington State University, University of Idaho.
  • Nampijja, M., Crane, S., du Toit, L., and Ocamb, C. 2021. Swiss chard – Bacterial leaf spot. In: 2021 Pacific Northwest Pacific Northwest Disease Management Handbook, J.W. Pscheidt and C.M. Ocamb, editors. A Pacific Northwest Extension Publication, Oregon State University, Washington State University, University of Idaho.
  • Nampijja, M., Derie, M.L., and du Toit, L.J. 2021. First report of bacterial leaf spot caused by Pseudomonas syringae pv. atata on Swiss chard, Beta vulgaris subsp. vulgaris, in Arizona. Plant Disease 105:3738.
  • Rieke, E.L., Cappellazzi, S.B., Cope, M., Liptzin, D., Mac Bean, G., Greub, K.L.H., Norris, C.E., Tracy, P.W., …Griffin-LaHue, D., …Morgan, C.L.S., Honeycutt, C.W., 2022. Linking soil microbial community structure to potential carbon mineralization: A continental scale assessment of reduced tillage. Soil Biology and Biochemistry. 168, 108618.
  • Shi, A., Bhattarai, G., Xiong, H., Avila, C.A., Feng, C., Liu, B., Joshi, V., Stein, L., Mou, B., du Toit, L.J., and Correll, J.C. 2022. Genome-wide association study and genomic prediction of white rust resistance in USDA GRIN spinach germplasm. Horticulture Research: published 23 Mar. 2022.
  • Shrestha, S., and C. Miles. 2022. Plastic mulch and in-row spacing effects on sweetpotato yield in northwest Washington. HortTechnology in press.
  • Solemslie, R., du Toit, L.J., Tracy, W.F., and Stearns, T. 2021. Evaluation of steam treatments for Fusarium spp. and other fungi on sweet corn seed, 2020. Plant Disease Management Reports 15:CF017.
  • Sullivan, D.M., A. Tomasek, D. Griffin-LaHue, E. Verhoeven, A.D. Moore, L.J. Brewer, A.I. Bary, C.G. Cogger, D. Biswanath. 2022. PNW 508: Fertilizing with Biosolids. Pacific Northwest Extension, in press.
  • Sullivan, D.M., D. Griffin-LaHue, B. Dari, A.I. Bary, C.G. Cogger. 2021. PNW 511: Worksheet for calculation biosolids application rates in agriculture. Pacific Northwest Extension.
  • Swisher Grimm, K.D., Crosslin, J.M., Cooper, W.R., Frost, K.E., du Toit, L.J., and Wohleb, C.H. 2021. First report of curly top of Coriandrum sativum caused by Beet curly top virus in the Columbia Basin of Washington State. Plant Disease 105:3313.
  • Una, T.M., D. McMoran, S.S. Seefeldt, B. Maupin, E. Myhre, D. Griffin-LaHue. Short-term impacts of cover crops in maritime potato (Solanum tuberosum) systems. Agrosystems, Geosciences, and Environment, in press.
  • Yu, Y., D. Griffin-LaHue, C. A. Miles, Douglas G. Hayes, and Markus Flury. 2021. Are micro- and nanoplastics from soil-biodegradable plastic mulches an environmental concern? Journal of Hazardous Materials Advances, 4: 100024.