WSU POTATO ALERTS-LATE BLIGHT UPDATE

This is a special issue of WSU Potato Alerts to review late blight management. 

NOTE: Late blight has not been reported in the Columbia Basin, but the conditions have been favorable for the disease to establish.  This is an important time to watch for it, especially in more advanced crops where the rows have closed.  These alerts are intended for commercial potato producers in Washington's irrigated Columbia Basin.  

LATE BLIGHT MANAGEMENT

• WEATHER
• SCOUTING 
• SYMPTOMS
• VOLUNTEERS & CULLS
• IRRIGATION
• FUNGICIDES
• IF YOU FIND LATE BLIGHT
• MORE INFORMATION

Late blight is one of the most dreaded diseases of potatoes.  We do not always see it in the Columbia Basin, but late blight does occur here and it can have devastating effects if you are not prepared.  

FAVORABLE WEATHER: Last week's late blight forecast estimated a 72% to 99% probability of late blight occurring in the Columbia Basin and Yakima Valley. These high probabilities are due to moderate temperatures and frequent storms bringing wetter conditions to the region. Late blight incidence in the Columbia Basin has been highest during growing seasons with several rainy days.

SCOUT FOR LATE BLIGHT:  Monitor plants thoroughly and often for symptoms.  Find it early before it spreads throughout the field.  Check low areas, wheel tracks, pivot centers, and anywhere else water tends to collect.  Since late blight spreads rapidly, you probably won't find symptoms on just one plant.  Instead, you will find symptoms on groups of plants, i.e., in "hot spots". 

The pictures below show "hot spots" from which late blight has spread. Photos by Tim Waters, WSU Extension.

To see full WSU Potato Alert please click this link

Questions or comments can be directed to:

Carrie H. Wohleb, Ph.D.
Associate Professor
Potato, Vegetable & Seed Extension Specialist
WSU Extension - Grant County - Columbia Basin

Tel: (509) 707-3510
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Hello Potato Alert Subscriber: This is the June 10, 2022 issue of WSU Potato Alerts, and the 5th regular issue for the 2022 growing season.  If this message was forwarded to you and you would like to subscribe, click HERE and choose "Potato Pest Alert" and any other topics that are important to you.  These alerts relate to commercial potato production in the Columbia Basin.