Potato Late Blight Update #7: June 19, 2015

Nathan Kleczewski, Extension Specialist – Plant Pathology; nkleczew@udel.edu

Note: Late blight on potato was confirmed in the Northeast part of North Carolina, approximately 30 miles from the Virginia border on 6/11/15.

  Townsend Smyrna Dover Fairgrounds
Date DSV Total DSV DSV Total DSV DSV Total DSV DSV Total DSV
5/11-5/15 1 1 1 1 8 8 1 1
5/15-5/22 3 4 3 7 2 10 3 4
5/22-5/28 0 4 0 7 0 10 0 4
5/28-6/5 24 28 15 15 8 18 5 9
6/5-6/11 12 36 5 20 6 24 3 12
6/11-6/19 11 47 8 28 6 30 3 15

Notes: Season severity of 18 severity values indicates the need for the first fungicide application. An accumulated severity of 7 after fungicide application identifies the need for a subsequent fungicide application.

Green row: May 11th, 2015

See the 2015 Commercial Vegetable Production Recommendations-Delaware for recommended fungicides.

Any suspect samples can be sent to the UD Plant Diagnostic Clinic, dropped off at your local extension office. Dr. Nathan Kleczewski can also be contacted at nkleczew@udel.edu or 302-300-6962.

The website USABlight tracks tomato and potato late blight across the nation and can be found here: http://usablight.org/. Information on scouting, symptomology, and management can also be found on this website.

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