Pacific Northwest Vegetable Extension Group

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

PNW-VEG Objectives (Poster)

  • Assist with diagnoses of vegetable diseases, pests, and other problems
  • Coordinate vegetable disease, pest, and production research and extension activities in the Pacific Northwest
  • Provide growers and gardeners with resources to manage vegetable diseases, pests, and abiotic problems in environmentally-sound ways
  • Publish new information about vegetable pathogens, pests and other problems; and their biology and management
  • Serve the region’s fresh vegetable, processing vegetable, and vegetable seed crop industries

The Pacific Northwest Vegetable Extension Group received the 2012 Interdisciplinary Team award from the WSU College of Agriculture, Human, and Natural Resource Sciences (CAHNRS); from left, Carol Miles (horticulturist), Dan Bernardo (CAHNRS Dean), Debbie Inglis (plant pathologist), and Lindsey du Toit (plant pathologist).

Vegetable Resource Highlights

  • Alert: Black leg in Brassicaceae Crops and Wild Crucifers. A widespread epidemic of black leg occurred on a diversity of crucifer oilseed, cover, forage, and vegetable seed crops in the Willamette Valley of Oregon in spring 2014. Black leg can be a significant problem for growers of fall- or spring-sown plantings of various crucifer crops, particularly under the favorable environmental conditions for this disease in the Pacific Northwest. Phoma lingam (sexual stage: Leptosphaeria maculans) is the fungus that causes black leg. In fact, back leg is a quarantine disease for five counties in northwestern Washington. Brassicaceae plants that can be infected include species of Brassica (e.g., broccoli, Brussels sprouts, cabbage, canola, cauliflower, various Chinese brassica vegetables, collard, kale, mizuna, mustard, oilseed rape, oilseed turnip rape, rutabaga, turnip, etc.), Sinapis (white and yellow mustard), and Raphanus (daikon and radish). Several wild species exist that may be infected by P. lingam.
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  • Disease Alert – Light Leaf Spot in Crucifer Seed Fields in the Willamette Valley. Beginning late March 2014, I found several leaf spot diseases in fall-sown crucifer crops and weedy species in the Willamette Valley. A survey in OSU research fields of fall-sown canola during late October in 2013 showed no leaf spots or seed/seedling diseases. However, light leaf spot caused by the fungus Cylindrosporium concentricum (sexual stage: Pyrenopeziza brassicae) was observed causing disease this spring in canola research fields as well as in commercial seed fields of forage Brassica species and “field” turnip. Light leaf spot was subsequently detected in other Brassica members including wild mustard, volunteer black mustard, vegetable Brassica seed fields, and Brassica species used as cover crops during 2014. While the specific host range for C. concentricum within the tribe Brassiceae is unknown at this time, it is likely that all brassicas crops grown in the Pacific Northwest are susceptible (1) with a range of susceptibility within each crop species. This disease hasn't been previously reported in North America, although an infected mustard field was found in western Oregon during 1998. Oilseed rape can be very susceptible with losses resulting from stand die-out, reduced pod numbers, and premature pod ripening; with less severe infections there is an overall growth reduction. Brassica species grown as vegetables in other areas of the globe, where this disease has been reported, suffer blemish defects that result in a decrease in quality but not quantity of yield.
    Read Full Alert...

    Disease Alert – White Leaf Spot in Crucifer Seed Fields in the Willamette Valley.
    White Leaf Spot and Gray Stem in Crucifer Seed Crops in Western Oregon, 2014 Beginning late March 2014, I found several leaf spot diseases in fall-sown crucifer crops and weedy species in the Willamette Valley. A survey in OSU research fields of fall-sown canola during late October 2013 showed no leaf spots or seed/seedling diseases. However, white leaf spot and gray stem caused by the fungus Pseudocercosporella capsellae (sexual stage: Mycosphaerella capsellae) were observed during 2014 in canola research fields as well as in commercial seed fields of forage Brassicas and “field” turnip. White leaf spot was also detected in volunteer black mustard and forage fields. Susceptible hosts reportedly include species of Brassica (broccoli, cabbage, canola, cauliflower, Chinese cabbage, mustard, turnip, etc.) as well as radish and horseradish. Weedy types such as wild radish, wild mustard, and shepherd's purse are susceptible to white leaf spot and gray stem.
    Read Full Alert...
    Potato Pest Alert 2014-16: This is the 16th potato pest alert issued for the 2014 growing season.

    POTATO PSYLLIDS:  We found psyllids on yellow sticky cards in 33% of the fields that we monitored as part of our insect monitoring network this week; the most we have encountered so far this season.  More were found on sticky cards brought to us by crop advisers.  Please note that potato psyllids have been found in almost all areas of the Columbia Basin this season, which means everyone should be taking steps to manage psyllids to minimize the impact of zebra chip disease.         

    I looked at two fields recently that have symptoms that could be the result of zebra chip, or might be something else.  The tuber symptoms are not conclusive (mild symptoms), but other symptoms are not quite consistent with other diseases that produce similar symptoms.  Plants from these fields are being tested for Liberibacter (Lso), the bacterium carried by potato psyllids that causes zebra chip disease and for BLTVA, the phytoplasma that causes purple top.  Irregardless, it is not likely that we will escape zebra chip this season.  The percentage of psyllids carrying Lso appears to be very low, but there ARE some Lso infected psyllids out there (several have been confirmed by the OSU HAREC Plant Pathology Lab) and they must be in someone's field.  If left uncontrolled, they can spread the disease and produce infected offspring that will spread it even more.  

    MANAGEMENT:  Despite low Lso infection rates in psyllids, you should take steps to control potato psyllids in your field.  Zebra chip can result in significant yield and quality losses, and it is not worth risking your crop.  Since more psyllids appear to be on the move right now, it is important to keep up with your foliar management program.  For more information about managing potato psyllids, read the potato psyllid section in IPM Guidelines for Insects and Mites in ID, OR, and WA by Schreiber, Jensen, Rondon, and Wenninger.

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  • New ‘Tomato MD’ App Helps Users Diagnose and Treat Sick Tomato Plants: Tomatoes are one of the most common crops in the U.S. But while popular, they are not always easy to treat when affected by plant diseases or bugs. With such a wide range of pests that affect tomato plants, growers can have a difficult time identifying and treating them.

    Enter Tomato MD, part of the new “Plant Health” family of apps for the iPhone or iPad. Tomato MD is an interactive reference that helps gardeners, professional growers, and consultants identify and manage more than 35 key diseases, insects, and physiological disorders of tomatoes.

    Tomato MD is unique in that tomato experts have peer-reviewed all content to ensure the images and information are accurate. And while the information was reviewed by scientists, it is very accessible and published in an easy-to-use, non-scientific format.

    Fact Sheet: Food Safety and Modernization Act (FSMA) Proposed Rule for Produce Safety: Standards for the Growing, Harvesting, Packing, and Holding of Produce for Human Consumption. The FDA’s website provides some highlights about the rule, who the rule covers, compliance information, and where to go for more information. This proposed rule has major potential ramifications for freshly consumed foods, including many vegetables.

  • Bacterial Ring Rot on Potatoes. Washington State University Extension Bulletin. This publication provides information on the bacterial ring rot pathogen, its disease cycle, and ring rot management on potatoes.

  • Production of Brassica Seed Crops in Washington State: A Case Study on the Complexities of Coexistence. Washington State University Extension Bulletin. The document was developed in response to the numerous controversial issues surrounding production of brassica vegetable seed crops, brassica oilseed crops, brassica oilseed seed crops, brassica cover crops, etc. in proximity given the risks of cross-pollination, introduction of seedborne, quarantine pathogens into some areas that are highly conducive to these pathogens, the prevalence of GMO traits in some brassica crops like canola vs. the zero-tolerance for GMO traits by many of the markets that buy brassica vegetable seed from the PNW, etc.

  • Brown Marmorated Stink Bug (BMSB). Oregon State University Department of Horticulture. Information on BMSB which is widespread in the Willamette Valley, and its possible damage to crops including vegetables.

  • News From the Field. August 14, 2012 issue of Onion ipmPIPE newsletter. Featuring the latest field observations from onion researchers around the country, this newsletter is designed to educate and inform growers, consultants, buyers, shippers and other onion industry stakeholders about the Onion ipmPIPE initative.

  • Grafting in Vegetable Production. Vegetable grafting is relatively new to the U.S. but is quickly gaining use, especially in greenhouse tomato production. Learn about vegetable grafting from these Extension publications and presentations.

  • Biology and Management of Aphids in Organic Cucurbit Production Systems. This article by Mary Barbercheck, Penn State University, provides an overview of the biology and life cycles, damage from, and management of the most common aphid pests in organic cucurbit crops.

  • Weed Management Strategies for Organic Cucurbit Crops in the Southern United States. Mark Schonbeck, Virginia Association for Biological Farming describes how to manage some of the most troublesome weeds of cucurbit crops in the South.

  • MSU’s Research results for bacterial canker in tomatoes. Research indicates it is best to manage canker before field planting tomatoes.

  • Bacterial canker ravages processing tomatoes. Learn how to recognize bacterial canker now to manage this disease in the future.

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from the Onion ipmPIPE
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Black Mold of Onion

Photo of onion maggot filesPhoto of onion maggot and maggot damage on onions
Onion Maggot

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