Vegetable Crops — Page 217 — Plant & Pest Advisory

Vegetable Crops Edition

Seasonal updates and alerts on insects, diseases, and weeds impacting vegetable crops. New Jersey Commercial Vegetable Production Recommendations updates between annual publication issues are included.

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August 2, 2016 Andy Wyenandt

Dickeya dianthicola update: 8/2/16

In addition to Dickeya dianthicola being found in potato fields in New Jersey, the pathogen has also been detected in fields from Long Island to Florida this summer. To date using PCR test results and North American Certified Seed Potato Health Certificates to track Lot No., the pathogen has been detected in 11 states (DE, FL, MD, MA, NJ, NY, NC, PA, RI, VA, and WV). Potato growers, crop consultants, and Extension personnel in states which grow potatoes from Maine or New Brunswick, Canada should remain vigilant by scouting their fields for Dickeya symptoms on a regular basis and by submitting any suspect samples for diagnostic testing. Dickeya dianthicola has been detected in the US in the past, and because of this, APHIS just recently announced that the pathogen has been designated as a non-reportable/non-actionable pathogen despite its potential to cause 100% crop loss. A link to the USDA/APHIS website for information on Dickeya dianthicola detection and control can be found here.

Unfortunately, there is a lot of misrepresentation of Dickeya dianthicola being presented to potato growers in the region.

Dickeya is not a significant problem. To date its has been detected in seed in 11 states, originating from 2 sources, from numerous suppliers. There is no current policy in place designed specifically for regulating and/or controlling Dickeya dianthicola in potato seed, although such policy has been presented in the past.
Dickeya is Blackleg. Dickeya is Dickeya, not Blackleg. Dickeya is seed-borne, Blackleg is soil-borne. Blackleg is caused by other ‘pecto’ or soft rot bacteria.
Dickeya is endemic. If so, why wasn’t it reported as causing significant problems in potato prior to 2015/2016. Even without proper testing available, it would have would been noticed enough by potato growers to cause concern/raise alarms.
Dickeya is the result of the current environment. What has changed between now and prior to its first detection in the US in 2014?
The disease is less severe 2016 than in 2015. Dickeya is being tested for and reported more often in 2016 now that it has been brought to the attention of potato growers.
Varieties differ in susceptibility to Dickeya. Dickeya has been detected in different lots of the same variety from different suppliers in 2016. Dickeya has also been confirmed in different varieties from the same supplier in 2016.

The best method for keeping your potato operation Dickeya-free is to adopt your own 0% Dickeya-tolerance policy.

For more information on Dickeya please see the following articles posted online – source(s) of information:

Dickeya: A new potato disease – Growing Produce

Blackleg is Once Again Being Observed in Potato Fields Across the Mid-Atlantic Region – Penn State University

Update on Dickeya detections in potato – University of Delaware

Dickeya Blackleg: New potato disease causing major impact. – Cornell University

Watch for Dickeya – a new potato disease – The Ohio State University

High security Aroostook farm advances tater technology. – Maine Potato Board

Slowing Dickeya, other pathogens in Canada. – North Dakota State University

Dickeya: A new threat to potato production in North America. – SPUDsmart

Dickeya is coming. – University of Wisconsin/North Dakota State University

Maine ‘Ground Zero’ for new potato disease. – Maine Department of Ag.

Maine seed potato growers looking to protect brand against disease. Maine Department of Ag./Maine Potato Board

Filed Under: Vegetable Crops Tagged With: Dickeya, Maine

August 1, 2016 Andy Wyenandt

‘Yukon Gold’ potato seed from Canada test positive for Dickeya dianthicola in U.S.

‘Yukon Gold’ (2015-3079137-010) certified by the Canadian Food Inspection Agency (CFIA) has tested positive for Dickeya dianthicola in Virginia this summer. This is the second report of Dickeya dianthicola in the U.S. originating from seed potato from New Brunswick, Canada this summer. Importantly, Dickeya-infested potato seed has also been shipped from multiple sources in Maine to 11 states located in the Northeast, mid-Atlantic, and Southeast regions this year. All potato growers are encouraged to scout fields and report any suspect plants/tubers. The best method for keeping your potato operation Dickeya-free is to adopt your own 0% Dickeya-tolerance policy.

Filed Under: Vegetable Crops Tagged With: Canada, Dickeya, potato

July 28, 2016 Andy Wyenandt

Reminder: Dickeya discussion at National Plant Board meeting in Wilmington, DE on Weds. 8/3

The National Plant Board will be holding their annual meeting in Wilmington, DE on July 31 to August 4th. The National Plant Board plays a significant leadership role in regulation and policy rules in agricultural production with each state having a representative member. One of the topics of discussion will be Dickeya dianthicola which has caused significant problems in potato production in NJ other states in the mid-Atlantic region. There will be presentations on Dickeya and seed potato production on the morning of Wednesday August 3rd starting at 8:15 AM. More information on the meeting and the schedule can be found here.

Filed Under: Vegetable Crops Tagged With: Dickeya, National Plant Board

July 27, 2016 Andy Wyenandt

Cucurbit downy mildew confirmed on cucumber in North Jersey 7-27-16

Cucurbit downy mildew has been confirmed on cucumber in Hunterdon County in Northern New Jersey. Downy mildew was found in cucumber in the southern part of the state a few weeks ago. To date, cucurbit downy mildew has only been reported in cucumber in the mid-Atlantic region. All cucumber growers who have not included a downy mildew-specific fungicide in their weekly spray program should do so. For more in formation on controlling cucurbit downy mildew please see the 2016 Mid-Atlantic Commercial Vegetable Production Recommendations Guide.

Filed Under: Vegetable Crops

July 27, 2016 Kris Holmstrom and Joe Ingerson-Mahar

Veg IPM Update: Week Ending 7/27/16

Sweet Corn

European corn borer (ECB) moth activity is slowly increasing and spreading northward (see ECB map) . This is the early part of the second flight. Very few larval infestations have been detected. Be sure to begin monitoring plantings for ECB feeding while they are still in the whorl stage. Consider treating when the number of infested plants in a 50 plant sample exceeds 12%. Feeding in the whorl stage will appear as numerous small holes (called “shot-hole”) on leaves, with damage present on consecutively younger leaves. As plants progress to pre-tassel and beyond, droppings and larvae may be found in or on the emerging tassels. Any planting remaining at or above threshold as it proceeds to full tassel should be treated, as this is the last stage at which ECB larvae will be exposed and vulnerable to insecticidal sprays. [Read more…]