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 24, 2024

Controlling Phytophthora blight in eggplant

Phytophthora blight, caused by Phytophthora capsici, can cause crown and fruit rot in eggplant. Unfortunately, most of New Jersey has been plagued by heavy rains and pop-up thunderstorms these past few weeks making conditions ideal for pathogens such as Phytophthora blight on pepper, eggplant, tomato, and cucurbit crops.

Control of Phytophthora blight is extremely difficult (even with the use of fungicides) in the very hot, wet weather conditions that most of New Jersey has been through during the month of July. In the past few years a number of new fungicides, with new active ingredients, have become commercially-available for use on multiple crops. Mefenoxam and metalaxyl, both once widely-used to effectively control Phytophthora blight have been hit by resistance issues around much of Southern New Jersey. Growers with a known history of mefenoxam-insensitivity on their farm should use Presidio or Ranman plus a Phosphite fungicide in rotation in their drip application programs for the control of the crown rot phase of Phytophthora blight. 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. Mefenoxam, metalaxyl, and the phosphite fungicides are the most systemic of the group and should readily be taken up the by plant via application through the drip. Orondis Gold (OXTP + mefenoxam) is also systemic. Presidio is locally systemic, and Ranman has protectant activity and can also be applied via drip.
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Filed Under: Vegetable Crops Tagged With: ,
May 23, 2024

Grape and Wine Science Certificate Program

Grape and Wine Science Certificate Program will be offered July 22-Aug 16, 2024. This program will provide foundational knowledge in three major areas of grape and wine science – grape growing, wine making, and business operations – following the path of grapes from the field to the winery to the glass. Students will gain competency in all three areas to prepare them for positions in the industry. The program will feature 4 weeks of classroom instruction, complemented by hands-on workshops. Then students will complete a 4-week winery internship where they can put their new knowledge and skills into practice. [Read more…]

Filed Under: Blueberry, Commercial Ag Updates, Cranberry, Fruit, Landscape, Nursery, & Turf, Nursery, Organic Production, Strawberry, Tree Fruit, Turf, Vegetable Crops, Wine Grape Tagged With:
May 23, 2024

Phytophthora and Pythium control during wet weather

Most of New Jersey has been wet making current conditions ideal for pathogens such as Phytophthora and Pythium. Unfortunately, Pythium cottony leak and 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 Phytophthora pathogen has an increasing host range that now includes snap and lima beans; and all crops, other than a few resistant bell pepper cultivars, lack any resistance to the pathogen. Under ideal conditions (hot, humid, and wet) Pythium cottony leak can develop on infected fruit.

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Filed Under: Vegetable Crops Tagged With: ,
May 22, 2024

Vegetable IPM Update 5/22/24

Sweet Corn

A few scattered European corn borer (ECB) moths have been captured in central and northern counties, and this insect is certainly active in southern parts of the state.  Numbers are very low, which is consistent with the last few seasons.   Whorl corn is the primary target for egg laying, but as yet, scouts have reported no signs of feeding injury in the few plantings that are of suitable maturity.  In northern and central counties, corn plantings that were started on/under plastic have reached a size that will support ECB larvae.  We expect to encounter some level of feeding over the next 2-3 weeks, although the majority of plantings have not required insecticide treatments for ECB prior to full tassel in the past several years.

European corn borerLook 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 damaged leafpyrethroids (IRAC Grp 3), spinosyns (including OMRI approved Entrust) IRAC Grp 5), and diamides such as Coragen or Vantacor (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 5/22/24 are as follows:

Asbury   1 Georgetown   1
Califon   1 Sergeantsville   1
Farmingdale   1 South Branch   1

*  No blacklight traps are in operation south of the Columbus (Burlington Co.) area this season.

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Filed Under: Organic Production, Vegetable Crops
May 22, 2024

Understanding and controlling angular leaf spot in strawberries

Often considered a minor pathogen, angular leaf spot caused by the bacterium, Xanthomonas fragariae, can cause serious leaf and calyx infections ruining the marketability of fruit if left uncontrolled. [Read more…]

Filed Under: Vegetable Crops Tagged With: ,
May 21, 2024

Identifying and controlling common leaf spot in strawberry

Strawberry leaf spot, caused by the soil-borne fungal pathogen, Mycosphaerella fragariae, can infect leaves, petioles, runners, fruit stalks (pedicels), and berry caps or calyxes. Small, dark purple to reddish-purple, round spots, 1/8 to 1/4 inch in diameter (3 to 6 millimeters), appear on the upper leaf surfaces. The center of the spots soon become tan or gray and eventually almost white, while the broad margins remain dark purple. Later in the season, dark specks (sclerotia and/or perithecia) may be seen in the older lesions. Tannish areas form on the undersides of infected leaves. The symptoms on the other plant parts, except the fruit, are almost identical to those that develop on the upper leaf surface. [Read more…]

Filed Under: Vegetable Crops Tagged With: , ,