Pacific Northwest Vegetable Extension Group

of Washington State University, Oregon State University, and University of Idaho

Newsletter Archives

June 2006 Newsletter

Lindsey du Toit and Debra Inglis, editors
WSU Mount Vernon NWREC
16650 State Rte 536, Mount Vernon, WA 98273-4768
360-848-6140 (tel), 360-848-6159 (fax)

WSU Vegetable Pathology Team Newsletter




Welcome to the June 2006 newsletter of the WSU Vegetable Pathology Team. We hope your season has started out productively! The focus of this newsletter is on recent changes to the WSU Vegetable Pathology Team, and two nematode pests of vegetable crops in the Pacific Northwest.



Field Days

The OSU Potato Field Day will take place at the OSU Hermiston Ag Research & Extension Center on June 22. For information contact Phil Hamm at or (541) 567-8321.

The WSU Potato Field Day will be at the WSU Othello Research Unit (6 miles East of Hwy. 26/17 Junction, S. of Hwy. 26) on June 23. For information contact Mark Pavek at or (509) 335-6861 or visit

The WSU Potato Cropping Systems Field Day will be in Paterson, WA on July 7. Further information can be found by calling (509) 786-9228.

The Famous Potatoes Field Day will be in Blackfoot, ID on July 18. For more information, contact Bryan Hopkins at or (208) 397-4181.

The WSU Onion Cultivar Demonstration will be at Brian Anderson's farm on the eastern Royal Slope of WA (Road D and Road 15.1 SE in the northern Columbia Basin) on August 11, starting at 10 am. For further information, contact Mark Trent at or (509) 754-2011 ext. 413.

The OSU Malheur Experiment Station Onion Variety Day will be on August 29 starting at 9:00 a.m. Information on the field day can be obtained at (541) 889-2174.

The WSU Watermelon Field Day will take place at the WSU Vancouver REC on August 30. Contact Carol Miles at or (360) 576-6030 ext. 20 for further information.

The OSU Sweet Corn Field Day will take place at the OSU Hermiston HAREC on September 7. For further information contact Phil Hamm at or (541) 567-8321.

The Organic Seed Alliance has a series of field days this year titled Producing Organic Vegetable Seed. The specific field days include:

  • Organic Spinach Seed Production & Crop Improvement, May 23 at Nash's Organic Produce in Sequim, WA.
  • Organic Diverse Seed Production & Crop Improvement, May 25 at Seven Seeds Farm in Williams, OR.
  • Organic Lettuce and Brassica Seed Production, Crop Improvement, Harvest & Cleaning, July 19 at Gathering Together Farm in Philomath, OR.
  • Organic Diverse Seed Production, Crop Improvement, & Seed Cleaning, August 22 at Eel River, Shively, CA.
  • Organic Green Bean Seed Production, Crop Improvement, Harvest & Seed Cleaning, September (date to be finalized) at Bryant Ranch in Shoshone, ID.
  • Organic Diverse Seed Production and Crop Improvement, September (date to be finalized) at Seven Seeds Farm in Williams, OR.

For more information about the field days, contact the Organic Seed Alliance at or (360) 385-7192, or visit the OSA website at Registration for any field day is $15 (lunch included).

2006 Vegetable Conferences

The 2nd International Biofumigation Symposium is in Boise, ID on June 25-28. Details on the symposium can be found at:

The WSU Organic Working Group is meeting in Ellensburg on July 12. For further information, contact Carol Miles at or (360) 576-6030 ext. 20.

The 2006 International Spinach Conference will take place in La Conner, WA on July 13-14, and will consist of a day of presentations and discussion on all aspects of spinach production; followed by a day touring spinach seed crops, other vegetable seed crops, and seed cleaning/processing facilities in Skagit and Island Counties. Further information can be found at:, or by contacting Lindsey du Toit at or (360) 848-6140.

The 2006 National Meeting of the American Phytopathological Society will take place in Quebec City, Quebec, Canada on July 28 - August 28. For further information, visit the APS website at:

The World Potato Congress will be held in Boise, ID on August 20-26. For details, see the congress website at:

The Integrated Pest and Nutrient Management Options: Practices and Tools to Protect Water Quality and Crop Yields Workshop will be in Corvallis, OR on November 8-9. For details contact Silvia Rondon at or (541) 567-8321.

The 2006 WA Tilth Producers' Conference will take place at the Red Lion Quay in Vancouver, WA on November 10-12. Visit the conference website at or contact Nancy Allen at (206) 442-7620

The 2006 Annual Convention and Trade Show of the Pacific Northwest Vegetable Association will be in Pasco, WA on November 15-16. For further information, visit the PNVA website at: or contact Sheri Nolan at 509-585-5460.

The 2006 National Allium Research Conference will be in College Station, TX on December 7-8. View the NARC website at for further information.

The Entomological Society of America will hold their annual meeting in Indianapolis, IN on December 10-13. See the ESA website for further details:



We are excited to announce that, as of 2006, the Washington State University Vegetable Pathology Team has expanded to a broader regional focus in the Pacific Northwest, and will now include members from the University of Idaho and Oregon State University. As a result, vegetable specialists from the Pacific Northwest region will contribute their expertise in plant pathology, horticulture and entomology to our team. To reflect this expanded mission and membership, the official team name has been changed to the:

Pacific Northwest Vegetable Extension Group (PNW VEG)
of Oregon State University, University of Idaho, and Washington State University.

Information on each of the new team members, including their areas of specialty and contact information, is shown below:

University of Idaho:Photo of Jef Miller
Jeff Miller’s current research at the University of Idaho focuses on the epidemiology and control of potato diseases. Diseases of primary interest include pink rot, late blight, early blight, black dot, and powdery scab. Current projects include evaluating the influence of cropping practices on pink rot incidence and severity, evaluating the interaction between fungicides and other pesticides on product efficacy, evaluating breeding material for disease resistance, and evaluating fungicides for disease control efficacy. The goal of Jeff's research program is to make disease control more effective and economical for potato growers. Jeff can be contacted at: or (208) 397-4181 ext. 108. See Jeff's potato pathology website at:

Oregon State University:

Photo of Phil Hamm

Phil Hamm has been with Oregon State University for over 31 years. Initially he worked with diseases of forest trees and problems associated with forest seedlings production in nurseries. Phil came to the Hermiston Agricultural Research and Extension center (in Hermiston, OR) in 1990, charged with development of a plant pathology program tied to high-value irrigated vegetable production area of the Columbia Basin. He oversees an extensive research and extension program which also includes a diagnostic facility responsive to growers in both Oregon and Washington. His research effort is concentrated on disease issues in potato (caused by fungi and viruses), sweet corn, grass seed, onions, and lima beans but has been involved with many other crops. Phil can be contacted at: or 541-567-8321.

Photo of Stacey Gieck

Stacey Gieck runs the Plant Pathology Laboratory at the OSU Hermiston Agricultural Research and Extension Center, working with Phil Hamm. The objectives of the lab are to assist in diagnosis of plant pathogens for growers in the Columbia Basin of Oregon and Washington, which consists of nearly 500,000 acres of irrigated agriculture; and to support research efforts of scientists at the experiment station. The lab is set up to diagnose pathogens from a variety of vegetable crops including, but not limited to, cucurbit, tomato, potato, onion and pepper. The laboratory has the capability to analyze samples by routine culture methods, ELISA, conventional PCR, and real-time PCR. Research efforts within the lab consist of optimizing new diagnostic and research protocols for use at the HAREC facility. Stacey can be contacted at: or (541) 567-8321 ext. 120.

Photo of Nick David

Nick David is a faculty research assistant working with Phil Hamm at the OSU Hermiston Agricultural Research & Extension Center. Nick obtained his BS degree in Soil & Crop Science at Colorado State University. Nick's research interests are in applied plant pathology and nematological issues related to irrigated agriculture. Nick can be contacted at: or (541) 567-8321 ext. 113.

Photo of Silvia Rondon

Silvia Rondon is assistant professor and extension entomologist at the OSU Hermiston Agricultural Research and Extension Center (HAREC), in the Department of Crop and Soil Science. Silvia's expertise is in biological control, insect biology and ecology, and population dynamics, with a focus on basic and applied research for field and greenhouse production. Silvia's research efforts are on integrated pest management including biological control, and cultural and pesticide screening for irrigated crops in eastern Oregon. Other interests include implementation of sustainable practices in irrigated crops, insecticide and miticide applications to reduce pest populations and their effects on non-target natural enemies. Silvia is collaborating with other entomologists and crop production practitioners to study pest biology, population characteristics; modeling; cultural, biological, and chemical control; and implementation and adoption of IPM practices. Silvia can be contacted at or (541) 567-8321.

Washington State University:

Photo of Don Moran

Don McMoran was hired in May 2006 as the WSU ExtensionAgriculture and Natural Resources Educator forSkagit County, WA. Don grew up on a potato farm in the Skagit Valley. Don graduated from Oregon State University with a Masters of Arts and Teaching in Agriculture Education, and a BS in General Agriculture with a Spanish minor. Most recently, Don worked for the Skagit Conservation District as a resource technician, writing and managing grants associated with conservation and restoration projects in Skagit Co. Don and his wife, Ami, make their home on the farm that has continuously been farmed by his ancestors for a century. Don can be contacted at or (360) 428-4270 ext. 225.

Tim Waters is the Area Extension Educator for Franklin and Photo of Tim Waters Benton Counties in the southern Columbia Basin of WA, with a focus on commercial vegetables and other irrigated cropping systems. Tim's program works on issues pertinent to commercial vegetable producers in the Columbia Basin. One focus is pest management in vegetables, including thrips management in dry bulb onions. Other research interests include improvement of cultural practices in vegetable seed production. A study aimed to determine proper timing for carrot seed harvest to insure uniform and high seed maturity will be conducted this season. In addition, work is being done on alternative cultivars and oilseed crop potential for the region. Several cultivars of carrots have been planted in the Columbia Basin to evaluate for their potential in commercial production in the region. Variety trials of soybeans and sunflower have also been planted to investigate their potential use for biodiesel production. Contact Tim at or 509-545-3511.


Photo of Lyndon Porter

Lyndon Porter is currently a Research Plant Pathologist with theUSDA-ARS in Prosser, WA addressing root rot and foliar disease issues with pea, chickpea, lentil and bean diseases. Currently Lyndon's program is involved in identifying cultural practices, chemical control, and resistance in pea germplasm to manage Fusarium root rot, Aphanomyces root rot, Pythium and different races of Fusarium wilt associated with peas. Besides working with root diseases, Lyndon's program is also screening pea germplasm for resistance to white mold and the Pea enation mosaic virus. Lyndon can be contacted at or (509) 786-9237.

These new members join current Vegetable Pathology Team members in their interest and commitment to the Pacific Northwest vegetable industry:


Questions on the potato cyst nematode and the nematodes in peas have recently been received by PNW VEG team members. Below are articles summarizing current information for these nematodes in the PNW. Refer to our August 2005 newsletter for a detailed article on nematode pests of vegetables in the PNW, including diagnostic resources and management recommendations:

A. Update on the Potato Cyst Nematode

Jeffrey S. Miller, University of Idaho
Ekaterini Riga, Washington State University
(With information adapted from the Golden Nematode Program Manual,, and

On April 19, 2006, officials at both the USDA Animal and Plant Health Inspection Service (APHIS) and the Idaho State Department of Agriculture (ISDA) announced that cysts of the potato cyst nematode (Globodera pallida) had been detected in a tare dirt sample from a potato grading station in eastern Idaho. The nematode does not pose a threat to human health, but can reduce the yield of potato crops. There has been no sign that the quality of crops grown in Idaho has been affected by this pest. Since the potato cyst nematode (PCN) is a quarantine pest, several trading partners have taken regulatory action. Japan has stopped all imports of U.S. potatoes, and Canada, Korea, and Mexico have stopped importing potatoes from Idaho. Official information updates on the status of PCN are currently being jointly issued by ISDA and APHIS and are available for viewing on the University of Idaho Potato Pathology web site:

Over 2,500 soil samples were collected from fields that could have been associated with the tare dirt sample. On June 13, 2006, PCN was identified from samples collected from one eastern Idaho field located in Bingham County. Potato production in this area is for processing and fresh market potatoes, and NOT for seed.

PCN is a soil-borne organism and does NOT infect potato tubers. The primary means of spread of PCN is by cysts being transported in soil on farming equipment, infested soil adhering to seed potatoes, and tare dirt. Again, the nematode does not infect potato tubers or seed. Spreading of potato cyst nematode via seed would only occur on soil adhering to the seed tubers. Once a farm is known to have PCN contamination, every precaution must be taken to prevent soil movement from the infested land. Farms free from PCN should take every precaution to ensure outside soil (i.e., soil from anywhere other than your farm) is not introduced.

Globodera pallida is closely related to Globodera rostochiensis, the golden cyst nematode, and under laboratory conditions they can interbreed. G. rostochiensis was identified on Long Island in New York in 1941. Since that time, the golden nematode has been reported in several counties in central New York State. The most effective management practice has been planting resistant plant varieties. Seeds of three varieties segregating for resistance to two pathotypes of G. rostochiensis (Ro1 and Ro2) and two pathotypes of G. pallida (Pa2 and Pa3) have been released by Cornell University and USDA/ARS. The resistance is suitable for North American production. They were developed in anticipation that pathotypes of G. pallida, which is prevalent in many other potato production areas of the world, would be introduced into North America. The combined resistance in this germplasm is from S. tuberosum ssp. andigena and S. vernei. (see, citing Brodie et al., 2000).
Information on the golden nematode and the USDA/APHIS management plan that has been successfully used in New York can be found in The Golden Nematode Program Manual, which is available online at: (The download is relatively large at 11.8 MB and may take a long time to access using a dial-up modem.)

Since PCN is spread in soil, all farming equipment used on suspected infested land must be pressure-washed to remove all soil. It is better to use a steam cleaner. All farms or businesses that are a potential source of PCN spread must be under state/federal compliance agreement. Types of regulated businesses include potato farms, potato processing and packing facilities, used farm equipment dealers, custom fertilizer applicators, utility companies performing work on infested land, surveyors, etc.

Potato seeds should be free of PCN. However, PCN can be transported in dirt adhering to potato tubers. Growers should follow the Best Management Practice of buying certified, clean seed and know their seed source well. It should be reiterated that the positive PCN finding in Idaho was NOT from a seed producing area.

Anyone entering a property where PCN is known to occur or suspected to exist must wear disposable plastic boots or clean and disinfect footwear by thorough brushing and scrubbing with a solution of one part 5.25% sodium hypochlorite (household bleach) in 10 parts of water. Bleach disinfectant kills all active stages of the nematode, but not the cysts. Other disinfectants may be effective, but none have been tested so no information is available on their effectiveness.

Vehicles or equipment used on land where PCN is known or suspected to exist must be power washed with a single orifice nozzle to remove all soil. Any equipment with inaccessible areas which cannot be guaranteed free from soil must be treated using a steam heat treatment. Sanitation procedures are extremely important for potato cyst nematode management and also for other soil-borne pests such as non-quarantined nematodes. Good sanitation practices should be implemented in potato production regardless of the concern of PCN.

Specific sanitation practices include:

  • Clean all machinery, trucks and other equipment when going from field to field. Do not allow any vehicles in fields unless the vehicles have been thoroughly cleaned.
  • Do not spread tare dirt or debris from potato processing operations or from storage filling/emptying operations on farm land or place it in an area where it can be spread to farm lands.
  • Leave hedgerows, sod barriers or sod strips between fields and along highways.
  • Grow non-host crops in long rotations with potatoes, and never plant potatoes back to back. Crops that are not hosts of potato cyst nematode include small grains, corn, sugar beets, and alfalfa. Avoid growing tomatoes and eggplants as rotation crops. Manage weeds as PCN can infect some nightshade weeds.
  • Plant cover crops as soon as possible when land is not in use. In the case of potato cyst nematode, cysts can be spread via wind erosion and carried in blowing soil.
  • Inform people in your operation of the seriousness of PCN and be sure they follow all precautions. Provide equipment needed to conduct proper cleaning and disinfection procedures.
  • Segregate potatoes in storage-each field should have a definite separation.
  • Do not use used bags, containers, etc. for potato transport, and be sure all commercial transport vehicles are free of soil.
  • Do not permit temporary help, custom applicators, or utility companies to bring their vehicles onto your farm land without proper sanitation and do not allow them to bring any bags, etc. with them to the field.
  • Do not use common headlands, farm roads and public roads as turning areas.
  • Do not assume that non-regulated fields are free of the pathogen in question.

Brodie, B. B.; Scurrah, Maria; Plaisted, R. L. 2000. Release of germplasm resistant to multiple races of potato cyst nematodes. American Journal of Potato Research 77: 207-209.

B. Nematodes in Peas:

Nematode Survey Recently Completed in Fresh and Dry Pea Production Regions East of the Cascade Mountains

By Lyndon D. Porter (USDA-ARS, Prosser, WA), and Nick L. David, Phillip B. Hamm and Russ E. Ingham (Oregon State University).

Members of the Pacific Northwest Vegetable Extension Group (PNW VEG) representing USDA at WSU Prosser and OSU completed a field survey in 2005 on plant pathogenic nematodes found in pea crops in the Columbia Basin of Washington and Oregon. Pea field managers, crop consultants and plant pathologists in the Columbia Basin region were asked to identify fields with nematode-like symptoms (stunted plant growth in circular patches within pea fields); these fields were then sampled to identify whether the patches were associated with nematode damage. Nematode juveniles were extracted from root and soil samples taken from both healthy and unhealthy areas of the patches in 36 green pea fields.

Plant pathogenic species recovered included the root lesion, root knot, stubby root and stunt nematodes from 8, 5, 4, and 5 sites in Oregon, and from 10, 9, 3, and 11 sites in Washington, respectively. Additionally, 1 and 4 sites from Washington contained pin and ring nematodes, respectively. When present in a field, plant pathogenic nematode densities were comparable in healthy and unhealthy areas, suggesting nematodes were not likely responsible for the observed damage within most of the fields surveyed.

Of particular importance was the fact that juveniles of the pea cyst nematode (Heterodera goettingiana) were not detected in the Columbia Basin survey. The pea cyst nematode has never been reported in dryland pea areas of the US. Based on the survey, there was no evidence that the pea cyst nematode is present east of the Cascade Mountain Range in Washington and Oregon. In 1993, the pea cyst nematode was found in pea fields located in western Washington, the first confirmed field reports of this nematode in the US. Identification of pea cyst nematode in western Washington proved a major concern to western Washington's pea industry because it has previously been associated with significant crop failures in other pea growing areas of the world. See WSU Extension Bulletin EB1872 on the biology and management of the pea cyst nematode:

The pea cyst nematode does best under cool and wet conditions often typical of western Washington, but is not favored by dry and hot weather which prevails in the Columbia Basin east of the Cascade Mountain Range where dry pea production is located.

Our pages provide links to external sites for the convenience of users. WSU Extension does not manage these external sites, nor does Extension review, control, or take responsibility for the content of these sites. These external sites do not implicitly or explicitly represent official positions and policies of WSU Extension.

WSU Mount Vernon NWREC, 16650 State Route 536, Mount Vernon, WA 98273-4768, 360-848-6120
Contact Us: Lindsey du Toit and Carol Miles