- Cucurbit downy mildew has been confirmed on cucumber in New Jersey. To date, cucurbit downy mildew has been reported on cucumber and melon in the mid-Atlantic region. Downy mildew is beginning to be reported on many other cucurbits in other parts of the country. All cucumber growers need to add a downy mildew-specific fungicide to their weekly fungicide programs. All cucurbit growers need to scout on a regular basis.
- Pepper anthracnose is being reported in southern New Jersey.
- Cucurbit powdery mildew is active on all cucurbit crops.
- There have been no new reports of Late blight this this past week.
September 13, 2016 Andy Wyenandt
Vegetable Disease Briefs – 9/13/16
September 6, 2016 Andy Wyenandt
Vegetable Disease Briefs – 9/6/16
- Cucurbit downy mildew has been confirmed on cucumber in New Jersey. To date, cucurbit downy mildew has been reported on cucumber and melon in the mid-Atlantic region. All cucumber growers need to add a downy mildew-specific fungicide to their weekly fungicide programs. All cucurbit growers need to scout on a regular basis.
- Dickeya dianthicola was confirmed in New Jersey on ‘Dark Red Chieftain’ originating from New Brunswick, Canada this past week. This is the third report of Dickeya on seed originating from Canada this summer. ‘Yukon Gold’ and ‘Reba’ from New Brunswick, Canada have also tested positive. In total, Dickeya dianthicola has been confirmed in 16 states to date. 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.
- Pepper anthracnose is being reported in southern New Jersey.
- Cucurbit powdery mildew is active on all cucurbit crops.
- There have been no new reports of Late blight this this past week.
August 25, 2016 Andy Wyenandt
Vegetable Disease Briefs – 8/25/16
- Cucurbit downy mildew has been confirmed on cucumber in New Jersey. To date, cucurbit downy mildew has been reported on cucumber and melon in the mid-Atlantic region. All cucumber growers need to add a downy mildew-specific fungicide to their weekly fungicide programs. All cucurbit growers need to scout on a regular basis.
- Dickeya dianthicola has been confirmed in 16 states to date. 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.
- Pepper anthracnose is being reported in southern New Jersey.
- Cucurbit powdery mildew is active on all cucurbit crops.
- Late blight was reported on tomato near Blacksburg, Virginia this past week.
August 22, 2016 Andy Wyenandt
Dickeya dianthicola reported in 4 more states: IN, MO, MI, and TX
Dickeya dianthicola has been reported in four more states (Indiana, Missouri, Michigan, and Texas). Using PCR test results and North American Certified Seed Potato Health Certificates to track Lot no., Dickeya dianthicola has been reported in 16 states (DE, FL, MD, MA, NJ, NY, NC, PA, RI, VA, WV, OH, IN, MO, MI, and TX) on at least nine potato varieties to date in 2016. These varieties include: ‘Reba’, ‘Superior’, ‘Vivaldi’, ‘Norwis’, ‘Snowden’, ‘Yukon Gold’, ‘Beacon Chipper’, ‘Kennebec’, and ‘Atlantic’. Test results and additional information are still forthcoming. Known sources of infested seed have originated from at least two suppliers in Canada and 11 seed suppliers in Maine. In some cases, multiple varieties of Dickeya-infested seed have originated from the same source in Maine. Potato growers, crop consultants, and Extension personnel in states which grow and are still harvesting potatoes from Maine or New Brunswick, Canada should remain vigilant by scouting their fields for Dickeya symptoms, particularly those varieties which have tested positive for Dickeya, 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. Importantly, there is no current policy in place designed specifically for regulating and/or controlling Dickeya dianthicola in potato in Maine or Canada.
The best method for keeping your potato operation Dickeya-free is to adopt your own 0% Dickeya-tolerance policy.
August 15, 2016 Andy Wyenandt
Vegetable Disease Briefs – 8/15/16
- Cucurbit downy mildew has been confirmed on cucumber in New Jersey. To date, cucurbit downy mildew has been reported on cucumber and melon in the mid-Atlantic region. All cucumber growers need to add a downy mildew-specific fungicide to their weekly fungicide programs. All cucurbit growers need to scout on a regular basis.
- There have been no new reports of Late blight in tomato or potato.
- Dickeya dianthicola has been confirmed in 12 states to date. 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. Click here for the latest Dickeya update.
- Pepper anthracnose is being reported in southern New Jersey.
- Cucurbit powdery mildew is active on all cucurbit crops.
August 10, 2016 Andy Wyenandt
Dickeya dianthicola update: 8/10/16
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 12 states (DE, FL, MD, MA, NJ, NY, NC, PA, RI, VA, WV, and OH). 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 12 states originating from 2 sources and a number of suppliers. In Maine, when dormant tuber testing was done for lots from 2015, there was approximately 16% incidence of Dickeya in 347 samples tested. In the dormant tuber testing for 2016, 25% tested positive for Dickeya out of 350 samples. Importantly, there is no current policy in place designed specifically for regulating and/or controlling Dickeya dianthicola in potato in Maine. There is also no way of knowing which of the above said lots (varieties) tested positive for Dickeya.
- Dickeya is Blackleg. Dickeya is Dickeya, not Blackleg. Dickeya is seed-borne. Blackleg is mostly soil-borne. Blackleg is caused by other ‘pecto’ or soft rot bacteria. Blackleg can be found in almost any potato field that has been in potato production in the past. Dickeya has only be found in fields planted with infested seed over the past few years.
- 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 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. Growers who received infested seed are reporting variable losses to Dickeya in 2016. Growers who have planted back into infested fields are also reporting poor plant vigor and variable yield losses.
- 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. Symptoms of Dickeya may appear different between cultivars.
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
