Vegetable Disease Alert

FRUIT AND VEGETABLES

From: Kelly Ivors, Lina Quesada-Ocampo and Barbara Shew, Extension Plant Pathologists

Late Blight Isn’t Late This Year . . . It’s Early Again

Late blight has been confirmed on tomatoes in Watauga, Guilford and Wake counties and on potatoes in Watauga County by the Plant Disease and Insect Clinic at North Carolina State University (http://www.cals.ncsu.edu/plantpath/extension/clinic/) in collaboration with Dr. Kelly Ivors and Dr. Lina Quesada-Ocampo at the Department of Plant Pathology.

Tomato fruit and foliage and potato foliage were severely affected and blighted in the samples, probably due to the heavy rainfall we have experienced in the past few days, which favors disease. In Western North Carolina, late blight on tomato typically occurs later in the season when the risks for fruit loss are minimal; however, it is only rarely found on tomato outside of the mountain counties. Given the recent rain and weather conditions and the fact that the disease is present in the state earlier than expected, the disease will be harder to control season-long and could quickly spread to other areas. Active scouting and immediate action to protect tomato and potato crops in North Carolina from late blight is recommended.

The Department of Plant Pathology has developed the Extension Plant Pathology portal (http://plantpathology.ces.ncsu.edu/), which contains a pest news section (http://plantpathology.ces.ncsu.edu/tags/pest-news/), to get the latest updated information on new pest alerts. We are constantly adding content as necessary when diseases of significance show up.

If you think you have late blight in your tomatoes and/or potatoes please contact your local Extension agent (http://www.ces.ncsu.edu/local-county-center/) and send photos and/or physical samples to the Plant Disease and Insect Clinic. If late blight is confirmed in your samples by an expert, please send a report at the USAblight website (http://www.usablight.org/) to alert other growers. The USAblight website also contains information about disease identification and control.

During the last two weeks the pathogen appeared in Dickson County, TN (June 7); Morgan County, TN (June 10) but in a greenhouse crop, which is an unusual circumstance; Montgomery County, MD (June 20); Wayne Co, KY (June 22); Mercer County, NJ (June 28); Kent County, DE (July 1) and of course as within the last couple of days - Guilford County and Wake County, NC. This monitoring system is complemented with available recommendations in the Southeastern U.S. Vegetable Crop Handbook, as well as an updated factsheet  (http://www.ces.ncsu.edu/fletcher/programs/plantpath/tomato-spray-guide/tomato-spray-guide-2013.pdf) that provides a proactive program to pre-empt late blight - especially during harvest.

For control recommendations and additional information, please refer to previous tomato late blight (http://plantpathology.ces.ncsu.edu/2013/06/pest-news-tomato-late-blight-alert-2/) and potato late blight (http://plantpathology.ces.ncsu.edu/2013/06/pest-news-potato-late-blight-alert/) alerts.

From: Lina Quesada-Ocampo, Extension Plant Pathologist

Cucurbit Downy Mildew Found in Sampson, Hertford and Martin Counties

Cucurbit downy mildew was found in cucumber in Sampson, Hertford and Martin counties and in butternut squash in Sampson County in the past five days. Growers should scout their fields twice per week and protect their crops. The continuous wet weather we have been experiencing will favor the disease. The forecast for cucurbit downy mildew risk in North Carolina continues to be high (http://cdm.ipmpipe.org/index.php?option=com_content&view=category&layout=blog&id=38&Itemid=61).

If you think you have cucurbit downy mildew in your cucurbits please contact your local Extension agent and send photos and/or physical samples to the Plant Disease and Insect Clinic. If cucurbit downy mildew is confirmed in your samples by an expert, please make sure a report is sent to the cucurbit downy mildew IPM pipe website (http://cdm.ipmpipe.org/index.php?option=com_wrapper&view=wrapper&Itemid=65).

For control recommendations and who to contact for assistance please refer to the first North Carolina report from Wayne County (http://plantpathology.ces.ncsu.edu/2013/06/pest-news-5313/), or check our factsheets in English and Spanish (http://projects.cals.ncsu.edu/veggiepathology/disease_factsheets).

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