Rutgers Cooperative Extension
New Jersey Agricultural Experiment Station
Plant & Pest Advisory
Date: 5/23/12 Alert Author: Andy Wyenandt
Pest: Late blight on potato in Burlington County (Central New Jersey)
Found: Late blight has been confirmed on potato in Burlington County, New Jersey.
Field Notes: Late blight was confirmed on actively sporulating leaf lesions from an 8 acre potato field in Cookstown, NJ (Burlington County). The few infected plants were found at the end of a row were the boom sprayer was most likely turned off. The grower had preventative applications of manzate followed by chlorothalonil prior. Seed pieces were sourced from Maine. This is the first report of Late blight in NJ on potato or tomato this year.
Crop(s) at risk: All potato (and tomato crops).
Potential impact: Significant losses may occur if not controlled properly.
What growers should do: Control of late blight begins with regular scouting, recognizing symptoms and preventative fungicide applications. All potato and tomato growers should scout fields and begin a regular preventative fungicide program if one has not been started. Adding a late blight specific fungicide to the tank mix should also be considered. Weather this past week has been ideal for late blight development in many areas of NJ (i.e., cool, wet, misty weather with heavy morning fogs).
Symptoms of Late blight mildew can be found here. https://www.google.com/search?q=late+blight&hl=en&rlz=1C1CHKZ_enUS439US439&prmd=imvns&tbm=isch&tbo=u&source=univ&sa=X&ei=wvS8TqGI6rZ6gGvkq1B&ved=0CGoQsAQ&biw=1280&bih=702
Commercial fungicide recommendations for controlling late blight can be found in the 2012 Commercial Recommendations Guide below.
Organic growers should consider applying a copper-based fungicide.
If you suspect late blight may be present on your farm, please let me know via email at email@example.com.