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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October 9, 2014

New Jersey Soils and Copper Fungicide Use

During my field visits to Mercer County organic farms, growers often express concerns about negative soil health impacts from copper based fungicides. In an effort to evaluate soil copper use and the resulting soil copper levels, soil was sampled at fifteen farms throughout the state.

NJ Sampled Soils

Soils sampled for copper levels.

Both conventional and organic farms participated in this study which was funded by The Phillip Alampi Fund. Two composite samples were taken from each farm, one where copper fungicides had been applied and one where copper fungicides had never been used. Total and soluble copper levels were higher on copper applied soils compared to the non-copper applied soils. Even though copper levels were higher in these soils, the levels were not high enough to cause plant toxicity symptoms, reduce plant growth, nor were the soils showing signs of reduced microbial activity.

Best management practices developed for copper based fungicides use:

[Read more…]

Filed Under: Commercial Ag Updates, Organic Production
October 3, 2014

Leaf blight in Dill

Leaf blight in Dill as shown up in the past week in some areas of southern New Jersey.

Leaflets on plants will appear wilted, often on the lower portion of the plant first. Up close, irregular lesions will appear scattered over the leaflets, girdling them, causing them to look wilted.

There have been a couple fungal pathogens associated with causing dill leaf blight. Options for controlling foliar pathogens in dill are extremely limited. Growers can apply Quadris (azoxystrobin, 11) at 15.5 fl. oz/A (O day PHI) alone or tank mixed with fixed copper on a 7 day schedule. Conventional growers can also apply a disinfestant, such as Oxidate, after overhead irrigation. Organic growers can apply OMRI-approved copper products. Other OMRI-approved products for leaf blight control may help suppress the pathogen.

Only overhead irrigate on sunny days in the in AM or early afternoon so planting can dry out.

Filed Under: Vegetable Crops Tagged With: ,
October 1, 2014

Vegetable Disease Update – 10/1/14

  • Cole Crops
  • Pumpkin
  • Spinach

Cole Crops

Downy mildew and Alternaria – Symptoms of downy mildew include purple to yellowish-brown spots on upper leaf surfaces. A grayish-white spore mass will develop and cover the underside of leaves under ideal temperatures (night temperatures of 46 to 61°F and day temperatures below 75°F). Downy mildew can kill young plants. Heavily infected leaves may drop providing entry points for bacterial infections (i.e., black rot and soft rot).

Symptoms of Alternaria on infected leaves include small, expanding circular lesions with concentric rings that may have a ‘shot-hole’ appearance as lesions age.  Heavily infected seedlings may result in damping-off.

Control of Downy mildew and Alternaria begin with preventative fungicide applications. Use one of the following at the first sign of disease and continue every 7 to 10 days (Please refer to the pesticide table on page F31 of the 2014 NJ Commercial Vegetable Production Recommendations to determine which fungicide is labeled for each specific crop.
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Filed Under: Vegetable Crops
October 1, 2014

Vegetable Disease Briefs – 10/1/14

Basil downy mildew remains active. The weather this time of year is ideal for downy mildew development across many crops. Growers should remain diligent going into the fall with regular scouting and preventative fungicide applications.

Cucurbit downy and powdery mildew remain active. Growers holding mature pumpkins in the field for the next few weeks should do their best to maintain the foliage for as long as possible to prevent potential sunscald injury. Late-season fungicide applications will also help keep powdery mildew off of the stems extending the pumpkin’s post-harvest longevity. Stems infected with powdery mildew will turn brown and dry out much quicker than healthier stems. Additionally, powdery mildew and downy mildew fungicide programs for all fall cucurbit crops should continue as along as harvesting continues.

There have been no new reports of Late blight this past week.  Growers with late-season tomato plantings should be diligent and scout on a regular basis. The cooler weather and prolonged dew periods are ideal conditions for Late blight development. All old plantings should be sprayed with gramoxone to burn the foliage down or mowed/disced under as soon as possible after the last harvest.

Filed Under: Vegetable Crops
October 1, 2014

Cold Injury in Cucumber

The effects of a cold night a few weeks ago are showing up in some varieties of cucumber around New Jersey. Symptoms on maturing fruit appear as brownish-tan areas on the epidermis of fruit. The fruit will also show cracking as if it has a dry rot. The effects are physiological where areas of young developing fruit got chilled by the cold night time temperatures.

Cuke_cold injury

Cold injury on cucumber fruit. The initial damage was done a few weeks ago while the fruit was very young.

Filed Under: Vegetable Crops Tagged With: ,
October 1, 2014

Veg IPM Update: Week Ending 10/1/14

Note: The backlight network is now being dismantled. Some traps will remain in operation for the next few weeks as crops continue. No maps will be produced for the remainder of the season, but pertinent pest information will be reported in subsequent weekly updates.

Topics for the Week

  • Sweet Corn
  • Tomatoes
  • Pumpkins and Winter Squash
  • Cole Crops

Maps for the Week
–Corn Earworm Moth Blacklight Trap Map
–Corn Earworm Moth Pheromone Trap Map

Vegetable IPM Report 10-1-14 – Click to View | Download | Print

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Filed Under: Vegetable Crops