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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June 12, 2019

IPM Update 6/12/19

Sweet Corn

European corn borer (ECB) moths catches have declined to nearly nothing over the past week (see map at left).  Feeding percentages have increased, and should peak over the next 5-7 days.  As of the weekend, feeding percentages as high as 24% in Cape May and 60% were found in whorl corn in Somerset County, but these numbers seem to be outliers. The majority of feeding is in the 2-14% range throughout much of the state.

 

 

ECB Tassel

Sweet corn emerging tassel with ECB droppings.
Photo: Kris Holmstrom

Growers should scout whorl and pre-tassel stage plantings weekly.  Look for the characteristic “shot-hole” type of feeding (photo below at right) and consider treating when infested plants exceed 12% in a 50 plant sample.  As plantings proceed to the pre-tassel stage, ECB larvae may be found in emerging tassels (see photo at left).  It is a good idea to treat individual plantings as they move into the full tassel/first silk stage one time.  This eliminates any ECB larvae that have emerged with the tassels as they begin to move down the stalk to re-enter near developing ears.

Useful insecticides for this particular application include synthetic pyrethroids (IRAC Grp 3), 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.

 

 

The highest nightly trap catches of ECB for the week ending 6/12/19 are as follows:

Califon   1 Milford   1
Hillsborough   1 Pedricktown   1
Medford   1 South Branch   1

[Read more…]

Filed Under: Organic Production, Vegetable Crops
June 12, 2019

Tomato Fruit Worm Found in Southern New Jersey

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Tomato fruitworm was confirmed in a tomato field in Gloucester County on June 12th. Tomato growers should be applying insecticides to control this pest when monitoring for eggs and small larvae result in seeing any signs of worm activity. There is no economic threshold for tomato fruitworm. When control is needed, it is essential to treat before large numbers of larvae enter fruit, where they are protected from sprays.

When there is fruit present, the tomato fruitworm will complete its larval development inside fruit. Early stage larvae enter the stem end of fruit when it is between 0.75 to 2 inches in diameter. During development, caterpillars may emerge from one fruit and enter another. Their feeding results in a messy, watery, internal cavity filled with cast skins and feces. Damaged fruit will ripen prematurely. Small larvae are difficult to detect and, thus, may be a problem to find. Any amount of feeding results in unmarketable fruit that will need to be culled at harvest or in the packing shed.

For insecticide recommendations see the 2019 Mid-Atlantic Commercial Vegetable Production Recommendations: https://njaes.rutgers.edu/pubs/commercial-veg-rec/tomatoes.pdf

Filed Under: Vegetable Crops
June 10, 2019

Vegetable Disease Update – 6/10/19

  • Phytophthora blight has been reported on pepper.
  • Southern blight was reported on tomato last week in southern New Jersey.
  • Bacterial leaf spot has been found on cabbage in southern New Jersey.
  • Cucurbit downy mildew has been reported as far north as South Carolina.
  • There have been no reports of late blight in the region to date.
  • 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.
Filed Under: Vegetable Crops
June 5, 2019

IPM Update 6/05/19

Sweet Corn

 European corn borer (ECB) moths catches have declined somewhat over the past week.  Overall this flight was very low, and appears to be on the way out.  The majority of moth activity at this time is along the Delaware Bay Shore (see map at left).  Feeding percentages should increase for the next 2 weeks, as eggs that have been deposited hatch.  As of this week, feeding percentages as high as 8-10% were found in whorl corn in Burlington County.  It is likely that feeding has exceeded the 12% threshold in many southern NJ plantings.

ECB Tassel

Sweet corn emerging tassel with ECB droppings.
Photo: Kris Holmstrom

Growers should scout whorl and pre-tassel stage plantings weekly.  Look for the characteristic “shot-hole” type of feeding (photo below at right) and consider treating when infested plants exceed 12% in a 50 plant sample.  As plantings proceed to the pre-tassel stage, ECB larvae may be found in emerging tassels (see photo at left).  It is a good idea to treat individual plantings as they move into the full tassel/first silk stage one time.  This eliminates any ECB larvae that have emerged with the tassels as they begin to move down the stalk to re-enter near developing ears.

Useful insecticides for this particular application include synthetic pyrethroids (IRAC Grp 3), 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.

 

 

The highest nightly trap catches of ECB for the week ending 6/05/19 are as follows:

Allentown   1 Crosswicks   1 Jones Island   1 Pennington   1
Califon   1 Folsom   1 Medford   1 South Branch   1
Centerton   1 Georgetown   1 New Egypt   1 Woodstown   1

[Read more…]

Filed Under: Organic Production, Vegetable Crops
May 31, 2019

Phytophthora blight control in wet weather

Most of New Jersey has been plagued by heavy rains and pop-up thunderstorms these past few days making conditions ideal for pathogens such as Phytophthora blight (P. capsici) on pepper, eggplant, tomato, and cucurbit crops. Now that the temperatures are starting to rise the threat of infection will only begin to increase. Unfortunately, Phytophthora blight can be found on most farms in the southern part of the state. Poor crop rotations with susceptible hosts only make matters worse. The pathogen also has an increasing host range that also includes snap and lima beans, and all other crops, other than a few resistant bell pepper cultivars, lack any resistance to the pathogen.

Control of Phytophthora blight is extremely difficult (even with the use of fungicides) in the extremely wet weather conditions that parts of New Jersey. In the past few years a number of new fungicides, with new active ingredients, have become commercially-available for controlling phytophthora on multiple crops. Mefenoxam or metalaxyl, both once widely-used to effectively control Phytophthora blight has been hit by resistance issues around much of Southern New Jersey the past decade. Growers with a known history of mefenoxam-insensitivity on their farm should use Presidio, Previcur Flex, or Ranman plus a Phosphite fungicide in rotation in their drip application programs. Importantly, if mefenoxam has not been used in particular fields on any crop for a number of years (more than 5+) the fungus may revert back to being mefenoxam-sensitive and control with these products may return. Orondis Gold, mefenoxam, metalaxyl, and the phosphites are the most systemic of the group and should readily be taken up the by plant via application through the drip. Presidio has locally systemic and has translaminar activity and offers protection of the root system via drip. Ranman has protectant-like activity and thus will offer root system protection.

For more information on these fungicides and specific crop uses, please see the 2020/2021 Mid-Atlantic Commercial Fungicide Recommendations Guide.

 

Filed Under: Organic Production, Vegetable Crops Tagged With:
May 31, 2019

Early-season Phytophthora blight control in pepper

Phytophthora blight typically develops in low-lying areas after a heavy rain and can spread quickly throughout the entire field. Fortunately, this spring in New Jersey has been really dry – too dry thus far, but that does not need you don’t need to prepare for potential phytophthora issues down the road. This is particularly important if are in fields with a known history of Phytophthora blight. Although the extended period of dry weather works against Phytophthora development, it can lead to Rhizoctonia root rot issues in newly transplanted plugs.

Cultural Recommendations

In general, planting on a ridge or raised, dome-shaped bed will help provide better soil drainage. In fields with known low-lying or wet areas, avoid transplanting in those areas all together. In fields with a known history of Phytophthora blight, plant ONLY resistant cultivars to help reduce plant losses. If mefenoxam-insensitivity is known to exist in a field/farm, plant only tolerant cultivars. Do not apply mefenoxam or metalaxyl in fields where insensitivity is known to exist.
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Filed Under: Organic Production, Vegetable Crops Tagged With: ,