- Basil downy mildew has been confirmed in southern and central New Jersey. All conventional basil growers should be on a preventative spray program prior to the arrival of the disease.
- Cucurbit downy mildew has been confirmed on cucumber as far north as Caroline County, Maryland and Sussex County, DE this past week. Cucurbit growers need to scout on a daily basis. All cucumber growers need to add a downy mildew-specific fungicide to their weekly fungicide programs.
- Reports of Dickeya dianthicola in potato continue across the east coast. Dickeya dianthicola has been confirmed in 10 states to date on potato seed originating from Maine and New Brunswick, Canada this growing season. All potato growers are encouraged to scout fields and report any suspect plants/tubers.
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July 10, 2016 Andy Wyenandt
Vegetable Disease Briefs – 7/11/16
July 6, 2016 Kris Holmstrom and Joe Ingerson-Mahar
Veg IPM Update: Week Ending 7/06/16
Sweet Corn 
European corn borer (ECB) moth catches remain very low now. Only scattered individuals are now being captured, and growers are managing residual infestations. At the present, the highest adult activity is in Salem county, although it is quite low even there (see ECB map). Larval feeding ranges from single digits to above 20% in areas where IPM personnel are operating. 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%. [Read more…]
July 5, 2016 Andy Wyenandt
Dickeya dianthicola affecting potato growers throughout Mid-Atlantic region and elsewhere – Updated 7/11/16
In addition to Dickeya dianthicola being found in ‘Superior’, ‘Reba’, ‘Snowden’, and ‘Norwis’ on 3 farms in New Jersey this year, the pathogen has also been detected in fields with seed originating from Maine on 5 farms on Long Island in ‘Reba’, ‘Vivialdi’, ‘Superior’, ‘Norwis’, and ‘Waneta’. Other varieties such as ‘Yukon Gold’ have also tested positive for Dickeya. The pathogen has been detected in MA, DE, PA, MD, VA, NC, WV, and FL this summer on seed from Maine and New Brunswick, Canada (NJ and VA). Maine potatoes are currently shipped to over 20 states across the country (CA, CT, DE, FL, ID, IN, KY, MD, MA, MS, NH, NJ, NY, NC, OH, PA, RI, TN, VT, VA, WA, WV, and WI). Potato growers, crop consultants, and Extension personnel in states which grow Maine potatoes 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.
For more information on Dickeya please see the following articles posted online – source(s) of information:
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
June 30, 2016 Andy Wyenandt
Vegetable Disease Briefs – 6/30/16
- Basil downy mildew has been confirmed in southern and central New Jersey.
- Cucurbit downy mildew has been confirmed as far north as Maryland this week.
- Bacterial canker in tomato has been reported.
- Angular leaf spot of cucumber has been reported. Water-soaked lesions similar to cucurbit downy mildew appear on the bottom of the leaves at first. In the case of angular leaf spot, caused by a bacterium, no spores will develop on the underside of leaves.
- Reports and sampling for Dickeya dianthicola in potato across the east coast continue.
June 30, 2016 Andy Wyenandt
Basil downy mildew confirmed in southern and central New Jersey – ALERT 6/30/16
Basil downy mildew has been confirmed on field-grown basil in southern and central New Jersey on 6/29/16. This is the first report of the pathogen in New Jersey and the mid-Atlantic region this growing season. All basil growers are encouraged to scout on a regular basis and initiate a protectant fungicide program if one hasn’t been started.
June 29, 2016 Kris Holmstrom and Joe Ingerson-Mahar
Veg IPM Update: Week Ending 6/29/16
Sweet Corn
European corn borer (ECB) moth catches remain very low now. The first flight is over, and growers are now managing subsequent infestations, which are generally lower than normal. Present adult activity is too low to generate a map image (<0.5 moths/night in all traps). Larval feeding ranges from single digits to above 20% in areas where IPM personnel are operating, although many plantings still have no detectable feeding at all. 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. Insecticides that are acceptable in organic production include the spinosyn based material Entrust (IRAC-5) and Dipel (IRAC-11a). The 10G formulation of Dipel is particularly useful when granules can be dropped or broadcast such that they get into the whorls of corn plants. Other effective insecticides include Coragen (IRAC 28), and the synthetic pyrethroids (IRAC 3). See the 2016 Commercial Vegetable Recommendations Guide for a more complete list of insecticides.
The highest nightly ECB catches for the previous week are as follows:
| Denville 1 | Matawan 1 |
| Farmingdale 1 | New Egypt 1 |
| Lawrenceville 1 | Old Bridge 1 |
| Little York 1 | Pennington 1 |
In addition, several low-level infestations of fall armyworm (FAW) were discovered this week. These were in Hunterdon and Middlesex counties, but it is likely that there are other light infestations throughout the state. These infestations have not exceeded 4% in the whorl stage, and are likely the result of a few FAW moths arriving in advance of weather fronts. This is somewhat early for FAW infestations in NJ, and we would expect to see little injury until mid-July. FAW feeding is much more obvious than that of ECB larvae, with large ragged holes and conspicuous droppings found in the whorl. FAW is resistant to synthetic pyrethroid insecticides (IRAC 3), and can be effectively managed with insecticides such as Radiant/Entrust/Blackhawk (IRAC 5) or Coragen/Besiege (IRAC 28). Consider treating if damage from ECB and/or FAW reaches 12%. [Read more…]
