According to the WSU Potato Pest Alerts:
The cool, rainy weather this week increases the probability that we will see late blight in the Columbia Basin. Late blight has not been reported in the Columbia Basin yet. Early season management tactics:
1) Restrict irrigation until the crop is fully emerged.
2) Form good sized hills over developing tubers.
3) Eliminate culls and tuber refuse.
4) Eliminate volunteer potato plants, especially in fields that had late blight last year or the year before. Volunteers in these fields run a high risk of being infected. In fact, infected volunteers have often been the source of several previous outbreaks in the Columbia Basin.
5) Begin monitoring fields for late blight when plants touch within rows and continue until harvest.
6) Good communications among growers when late blight is present is essential for minimizing late blight outbreaks in the region. This disease spreads very quickly.
Contact Rachel Bomberger at the Plant Pest Diagnostic Clinic rachel.bomberger@wsu.edu(509) 335-3292 to report, confirm or to make a late blight diagnosis.
This picture shows late blight on a newly emerged potato plant from an infected seed piece. This photo is courtesy of D.A. Inglis and J. Gigot, WSU.
