Vegetable Crops — Page 183 — Plant & Pest Advisory

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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May 31, 2019 Andy Wyenandt

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: Phytophthora blight

May 31, 2019 Andy Wyenandt

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.
[Read more…]

Filed Under: Organic Production, Vegetable Crops Tagged With: pepper, Phytophthora blight

May 31, 2019 Andy Wyenandt

Vegetable Disease Update – 5/31/19

Downy mildew in pea has been reported in southern New Jersey.
Bacterial leaf spot of parsley has been reported in southern New Jersey.
Cucurbit downy mildew has been reported as far north as southern Georgia.
Weather the past week has been ideal for downy mildew development on spring crops. Growers are advised to scout fields on a regular basis
The heavy rains and warmer weather have been ideal conditions for early-season damping off caused by Pythium root rot and Phytophthora crown rot. Growers should continue to scout on a regular basis and remain proactive in their fungicide programs as long as current weather patterns continue.
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

May 29, 2019 Kris Holmstrom and Joe Ingerson-Mahar

IPM Update 5/29/19

Sweet Corn

IPM Personnel are still capturing low numbers of European corn borer (ECB) moths, although even these captures are fairly sporadic, and extremely low in the northern counties (see map at left). Despite this, single digit feeding percentages were found on Middlesex county whorl stage corn on Wednesday of this week. It is likely that ECB injury has occurred on early plantings in most areas, although it is probably very light. Early plantings grown under plastic will be at risk first, followed by the first bare ground plantings. Growers should begin scouting whorl corn for injury.

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

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 5/29/19 are as follows:

Downer 2	Centerton 1	Hillsborough 1
Medford 2	Elm 1	Jones Island 1
Califon 1	Folsom 1	Oldwick 1

[Read more…]

Filed Under: Organic Production, Vegetable Crops

May 23, 2019 Rick VanVranken

Does My Business Need A Spotted Lanternfly Permit?

With the closing of the Purdue grain facility in Bordontown, field crops growers are sending trucks to southeastern PA to deliver grain, and produce shippers and others may be working/delivering to warehouses there too. Burlington County Agricultural Agent Bill Bamka shares the following information about shipping into or out of Spotted Lanternfly (SLF) quarantine zones (including some northwestern NJ counties):

Spotted Lanternfly adult with wings spread. Adults are about 1″ long

Spotted Lanternfly is an invasive insect recognized as a threat to agriculture in New Jersey and the United States. Multiple states in the Mid-Atlantic area have SLF populations and/or quarantines in place. Currently New Jersey has quarantines in Warren, Hunterdon, and Mercer counties. Pennsylvania has a quarantine area of 14 counties across the southeastern portion of the state. [Read more…]

Filed Under: Commercial Ag Updates, Field, Forage & Livestock, Fruit, Landscape, Nursery, & Turf, Uncategorized, Vegetable Crops

May 23, 2019 Andy Wyenandt

Controlling Septoria Leaf Spot and Bacterial Leaf Blight in Parsley

Septoria leaf spot (SLS) in Parsley can cause significant losses in fields where it has become established. Like other Septoria’s, the leaf spots produced on parsley look much like the leaf spots produced on tomatoes and other crops. Septoria leaf spot overwinters from year to year on infected debris so long crop rotations of 2 or more years are important to help reduce disease pressure. During the season, SLS will spread rapidly with each subsequent rainfall and/or overhead irrigation event. Therefore, early detection and preventative fungicide applications are key to successfully controlling SLS. Unfortunately, very few fungicides are currently labeled making control difficult.