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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Vegetable IPM Update 10/02/19

Note:  This is the last regular edition of the Vegetable IPM Update for the season.  We will provide additional updates on specific pest/disease issues as they arise.

Sweet Corn

Corn earworm (CEW) moth catches remain at moderate levels.  Overall, CEW numbers represent a normal early fall population.  Moth counts will decline with cool night temperatures (especially those forecast for the upcoming weekend), but look for rebounds when nighttime temperatures exceed 60F.   Economically damaging populations of this pest are present throughout the state, and all remaining silk stage plantings are at risk of crop injury if strict spray schedules are not observed.

 

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Vegetable IPM Update 9/25/2019

Joe Ingerson-Mahar and Kris Holmstrom

This is an abbreviated edition of the IPM Update.  The final IPM Update for the 2019 season will appear next week.  Pest alerts will appear as needed.

 

Sweet Corn

European corn borer (ECB) remains at very low levels across most of the state, with a few moths (1 per night) being found in the Hillsborough and Milltown areas this past week.  Late-season plantings are still at risk from ECB feeding but are likely to be minimal at this point.  In the late-season corn borers tend to lay eggs on many different crops, including apples and eggplant, so do not be surprised that you find ECB on unexpected crops.

Corn earworm (CEW) numbers have fallen somewhat across the state with the generally cooler night-time temperatures of the past week.  Counts in both blacklights and pheromone traps are highly variable across the state.

Blacklights – counts statewide range from 0 to 5 moths per night with larger numbers in the southern half of the state.  Spray schedules range from 4 to 5-day to 3-day.

Pheromone traps – counts have also declined somewhat, due both to cooler weather and aging sweet corn.  Plantings that are tasseling now will be the most attractive to CEW moths and these plantings should be on 3-day schedules, especially in South Jersey where despite declining numbers there is still a large reservoir of moths in the area.  Highest counts seen are at Eldora with 58 moths per night and Beckett with 48 moths per night.  The pheromone traps are showing a 4-day or 3-day schedule.

Fall armyworm pressure has been light in at least the southern part of the state.  Infestations of less than 10% are the norm.

Peppers

Corn earworm numbers have been high in pheromone traps placed at pepper fields.  Some injury has been found from these pests where insecticide applications have been backed off.

Beet armyworm continues to be a significant pest in the southernmost part of the state with counts at 73 per night at Jones Island and 32 per night at Pedricktown.  Traps in Hammonton record less than 10 per night.  Plant injury has occurred at counts under 5 per night.

Pepper weevil has become a widespread pest with now at least 8 farms infested in the Swedesboro, Glassboro, Hammonton and East V

Adult weevil on pepper

ineland areas.  It is hard to estimate yield loss to weevils but most of these farms probably have light to moderate loss.  Two of the farms had severe losses from weevils this year.  Farms that are located near, or do business with, processors should routinely have yellow pheromone traps placed in high traffic areas on the farm and in fields.  Weevils are most likely to be transported to the farm by hitchhiking on vehicles or on produce bins, though they are capable of spreading on their own to adjacent fields of solanaceous crops.

Other insect pests

Brown marmorated stinkbug has nearly become absent in blacklight trap catches.  At this time of year, they are seeking ov

Hawaiian beet webworm on spinach

erwintering sites and do not present much of a problem for vegetable crops.  Centerton had the highest nightly count of 2 for the past week.

Hawaiian beet webworm (HBWW) moths have been trapped in blacklights in South Jersey – Jones Island and Eldora.  Though the numbers are light, farmers with spinach, beets, and chard should check their fields for the presence of webbing and feeding injury.  These are small migratory moths usually occurring in mid-to-late summer.  Their favored host is the pigweed, Amaranthus sp., but they are capable of causing defoliation and contamination to crops.  Since they are migratory and have a short life cycle they can rapidly appear and cause extensive damage to crops unnoticed.  There were isolated highly-infested weedy areas last year on vegetable farms in South Jersey.

Twilight Meeting 10/10: Cleaning and Sanitizing Grading Equipment

Join us at the Rutgers Snyder Research Farm to discuss the cleaning and sanitizing of produce grading equipment.

October 10, 2019  from 4:00 p.m. to 7:00 p.m.

This event is free but please register through Eventbrite or call Brandi at 856-451-2800

Cleaning and Sanitizing Grading Equipment

Allium leaf miner update: 09/20/19

Allium Leaf Miner

Allium leaf miner (ALM) feeding/egglaying scars were detected in chives and scallions near Princeton (Mercer Co.), NJ on Friday of this week.  This indicates that the second (fall) flight of these flies is now underway, and damage is occurring.

Allium leafminer oviposition scars on onion

Photo: Sabrina Tirpak. Allium leafminer oviposition scars on onion

Growers should consider initiating the control method of their choice at this time.  Affected crops include chives, scallions, garlic, onions and leeks.

Floating row covers, kept on until the second flight ends will help minimize access to plants.  Insecticide applications targeting adults may be helpful as well, although frequency of applications is uncertain.  Spinosyn materials (Radiant, Entrust (OMRI approved)), pyrethroids (Mustang Maxx, Warrior), and pyrethrin materials (Pyganic (OMRI approved)), neonicotinoids (Scorpion, Venom) and the insect growth regulator Trigard are labeled for miner control.

Adult activity and observations of feeding will be reported on in the IPM Update as they occur.  At this time, all growers should respond to the second adult generation.  We will attempt to identify the end of the second flight so that growers know when the risk of infestation has abated.

 

 

 

Vegetable Disease Update – 9/17/19

  • All cucurbit growers are encouraged to scout their fields on a regular basis and continue to use a downy mildew specific fungicide program. Fungicides that are specific to CDM should be included in weekly fungicide maintenance programs for cucurbit powdery mildew control. To track the progress of CDM in the US please visit the CDMpipe forecasting website here.
  • Basil downy mildew has been reported in New Jersey on BDM susceptible and resistant sweet basil lines. All basil growers should continue to scout and follow a BDM specific fungicide program even when using DMR varieties. To track the progress of BDM in the US please visit here.
  • Downy mildew has been reported in turnip greens. Growers who have fall leafy greens and cole crops should scout daily and be proactive and initiate a regular downy mildew specific fungicide program. Although its been relatively dry, spotty showers, cooler nights, and longer periods of dew (leaf wetness) have made conditions ideal for downy mildew development across a number of susceptible crops.
  • Pepper anthracnose continues to be reported.
  • The 2019 Fungicide Resistance Management Guide for Vegetable Crops in the mid-Atlantic Region is now available for FREE online.
  • For more information on controlling these and other important diseases please see the 2019 Mid-Atlantic Commercial Vegetable Production Guide. The guide is available for FREE online by following the links on the Plant and Pest Advisory website. Hardcopies of the 2019 guide can be purchased through your local county Extension office.

Vegetable IPM Update 9/18/19

Sweet Corn

European corn borer (ECB) moth captures remain scattered and very low, and no map will appear in this addition.  There are very few plantings not yet silking.  Silk sprays for corn earworm (CEW) control will serve to manage ECB larvae as well.  Reminder:  Useful insecticides for worm control in the silk stage include  spinosyns (including OMRI approved Entrust) IRAC Grp 5), and diamides such as Coragen (IRAC Grp 28) or materials such as Besiege which include the active ingredient in Coragen.  Synthetic pyrethroids alone should NOT be used for corn earworm (CEW) protection on silking corn.  Control with these materials is very inconsistent.

 

Corn earworm (CEW) moth catches have changed little in NJ this past week.  Overall, CEW numbers represent a normal late summer population.  While moth counts will decline somewhat with cool night temperatures, look for strong rebounds when nighttime temperatures exceed 60F.  The green area on the blacklight map (left) represents a 3-day silk spray schedule zone.  Blue and white areas within the overall green zone are outliers, and corn growers in or near those areas should also adhere to 3-day silk spray schedules.     Economically damaging populations of this pest are present throughout the state, and all areas are at extreme risk of crop injury if strict silk spray schedules are not observed.   Red areas on the on the pheromone trap map (below at right) indicate a 3-day silk spray schedule, while green indicates a 4-5 day silk spray schedule.  Currently, the black light network is indicating a more conservative spray regime statewide, than is the pheromone network.  Taken together, blacklight and pheromone traps are indicating 3-day silk spray schedules throughout the state.  There are far fewer CEW pheromone traps than blacklights, and the resulting map has much broader color bands as a result.  It should also be noted that the pheromone traps are much more sensitive than blacklights.  Therefore, the number of moths caught in pheromone traps required to generate a specific spray interval is much higher than the number caught in blacklight traps.   It must be stressed that there is high variability in these catches, and growers should consult with their IPM practitioner on recommended spray schedules.

 

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