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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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September 22, 2016

Organic potato growers in New Jersey not immune to Dickeya dianthicola.

As the season begins to wind down for many organic farmers in New Jersey and the rest of the mid-Atlantic region, the question now becomes where to get potato seed for next year? Using PCR testing and North American Certified Seed Potato Health Certificates to track lot numbers, 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’, ‘Atlantic’, and ‘Chieftain’.  A few of these varieties (Yukon Gold, Kennebec, and Chieftain) are grown organically in New Jersey and are bought through growers/distributors in Maine as well as other States.

Organic potato growers in New Jersey (and the region) who are currently looking for sources of seed for next season need to do their own due diligence and avoid those varieties and operations which have proven to be a source of Dickeya. Importantly, organic growers need to pay close attention and ask where their seed originated and for the accompanying North American Seed Health Certificate. This certificate will tell you where the seed was produced and by whom. As a note, organic seed suppliers who do not produce their own seed can purchase and re-sell seed from other seed growers. This seed may be organically or conventionally produced depending on whether there is a source of organic seed available or not. Checking the Production Environment Pedigree on North American Seed Health Certificate to know where the lot was grown in previous years and/or originated may also provide valuable information for potential Dickeya infestation since most of the seed bought in the region is year FY4 or FY5. Remember, a North American Seed Health Certificate with a 0% Blackleg reading does not mean the seed lot is necessarily free of Dickeya. The only way to know is to have the lot tested specifically for the pathogen using PCR and/or to cross check that lot with other seed from the same lot that may have or may not have been tested and sold to others. Organic potato growers need to follow the same best management practices as conventional growers.

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: , ,
September 21, 2016

Veg IPM Update: Week Ending 9/21/16

Sweet Corn

European corn borer (ECB) moth numbers have decreased this past week such that only a handful of moths were captured.  There are no particular areas of higher activity, and  no map will appear in this edition. It is unlikely that we will realize any further injury from this pest this season.

The highest nightly ECB catches for the previous week are as follows:

Cinnaminson   1 Milltown   1
Clinton   1 Pedricktown   1
Hillsborough   1 Sergeantsville   1

[Read more…]

Filed Under: Vegetable Crops Tagged With: , , , ,
September 20, 2016

Best management practices for reducing Dickeya dianthicola in potato in NJ.

As the potato season is winding down in New Jersey (and other states in the mid-Atlantic region), it is time to begin thinking about sourcing seed for next season. Below is a list of best management practices to help reduce the chances for Dickeya dianthicola in your potato operation.

  1. All potato growers are strongly encouraged NOT to purchase those varieties (with lot numbers) which are known to have Dickeya from any source.
  2. All potato growers are strongly encouraged not to purchase seed from those growers/brokers with a known history of Dickeya.
  3. Potato growers SHOULD NOT rely on Blackleg tolerance levels reported on the North American Seed Health Certificates or the Florida Test results for presence of Dickeya in ANY seed lot from ANY source.
  4. Ask the grower/supplier if the field of seed origin was rogued for “Blackleg”.
  5. Any grower which rejects a load of seed for suspect Dickeya should report information to your local Extension Agent, Extension Specialist, or Potato Growers Assoc.
  6. Request PCR testing for Dickeya dianthicola from supplier (directly from grower/or broker) using an independent lab. Reject any load if no Dickeya test results are available or those seed lots that have tested + for Dickeya.
  7. Growers are encouraged that each truckload brought to the farm operation be sampled and re-tested for Dickeya once delivered. All results should be reported to your local Extension Agent, Extension Specialist, and/or Potato Growers Assoc.
  8. All growers are encouraged to report every variety, lot number (North American Seed Cert), field (general) location, and testing results each spring so Dickeya can be tracked and that this information be publically available to all potato growers in and out of the state.
  9. Fields with a known history of Dickeya should not be planted back into potato for at least 3 years or longer. Avoid planting brassicas and onions in potato rotations, especially in fields with a history of Dickeya.
  10. Growers using surface water (pond or stream) should be encouraged to do monthly water testing for Dickeya, especially if water source is near field with known Dickeya infestation.
  11. Wash/dump water needs to be displaced in an area away from packing shed, particularly those sheds near any production field or source of ground water that may be used for irrigation.
  12. Culled fruit needs to be dumped away from any production field, source of ground water, or any area where contamination of equipment may occur.
  13. All potato growers with fields with Dickeya-suspect symptoms need to be sampled and tested during the growing season.
  14. Rogue or volunteer plants appearing in fields with known Dickeya infestation the previous year or any prior year need to be removed, and/or sampled and tested if “Blackleg” symptoms present.
  15. All equipment during seed piece cutting needs to be disinfested on a regular (daily) basis, and/or disinfested between lot numbers and/or varieties. Quaternary ammonium is a good option for this purpose.

Remember, after doing your due diligence if you as a customer are not satisfied with the seed or information regarding the seed you should seek another source. 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’. Tuber and water test results are still forthcoming. Known sources of infested seed have originated from New Brunswick, Canada and Maine in our state and region this summer. In some cases, multiple varieties of Dickeya-infested seed have originated from the same source. Potato growers, crop consultants, and Extension personnel in states which grow and are still harvesting 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. Thus, any seed originating from Canada or other regions in the US should be carefully vetted. 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 the US or Canada.

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: ,
September 14, 2016

Veg IPM Update: Week Ending 9/14/16

Sweet Corn

16ecb0914aEuropean corn borer (ECB) moth numbers increased slightly this past week.  At the present time, highest activity is in western areas from the Delaware Bay shore northward to Warren County (see ECB map). This partial third flight should not present much of a threat to host crops.  This is particularly true in light of the dominance this year of fall armyworm (FAW). FAW will probably remain the larger threat, and treatments for this pest will eliminate ECB in the process. See the 2016 Commercial Vegetable Recommendations Guide for insecticide choices.

 

 

The highest nightly ECB catches for the previous week are as follows:

Allentown   1 Lawrenceville   1
Crosswicks   1 Pennington   1
Downer   1 Phillipsburg   1
Georgetown   1  Sergeantsville   1

 

There has been little change in the fall armyworm (FAW) situation in the north and central areas.  Joe Ingerson-Mahar indicates that re-infestation rates in younger corn in the southern counties have declined somewhat.  Infestations continue throughout NJ, with damaging infestation rates in all parts of the state.  We should expect this pest to be with us for the remainder of the sweet corn growing season.  Treat when FAW alone or in combination with ECB damage exceeds 12% plants infested.  FAW do not respond well to pyrethroid insecticides.  The most useful products are those in the IRAC group 28 class (Coragen, Exirel) or the IRAC group 5 class (Radiant, Entrust), or combination products including these classes.  See the 2016 Commercial Vegetable Recommendations Guide for insecticides effective against FAW.

  [Read more…]

Filed Under: Vegetable Crops Tagged With: , , , ,
September 13, 2016

Vegetable Disease Briefs – 9/13/16

  • 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. 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.
Filed Under: Vegetable Crops Tagged With: ,
September 7, 2016

Veg IPM Update: Week Ending 9/07/16

Sweet Corn

16ecb0907aLow numbers of European corn borer (ECB) adults continue to be captured this past week.  At the present time, highest activity remains in the Cape May-Cumberland County border area (see ECB map). Earlier ECB catches were extremely low, and these moths, likely representing a partial third flight, will not present much of a threat to host crops.  This is particularly true in light of the dominance this year of fall armyworm (FAW). FAW will probably remain the larger threat, and treatments for this pest will eliminate ECB in the process.  As always, consider treating when the number of infested plants in a 50 plant sample exceeds 12%. 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. See the 2016 Commercial Vegetable Recommendations Guide for insecticide choices.

The highest nightly ECB catches for the previous week are as follows:

Green Creek  2 Hillsborough   1
Allentown   1 Lawrenceville   1
Crosswicks   1 New Egypt   1
Downer   1  Pedricktown   1

 

There has been no change in the fall armyworm (FAW) situation.  Infestations continue throughout NJ, with high infestation rates in all parts of the state.  This pest is devastating to small corn plants, and in fact the worst infestations are currently in shorter whorl stage plantings.  Fields down to seedling stage should be scouted weekly for signs of infestation. We should expect this pest to be with us for the remainder of the sweet corn growing season.  Treat when FAW alone or in combination with ECB damage exceeds 12% plants infested.  FAW do not respond well to pyrethroid insecticides.  The most useful products are those in the IRAC group 28 class (Coragen, Exirel) or the IRAC group 5 class (Radiant, Entrust), or combination products including these classes.  See the 2016 Commercial Vegetable Recommendations Guide for insecticides effective against FAW.

  [Read more…]

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