- Powdery mildew has been reported in cucurbit crops. For more information on the control of CPM please click here.
- Cucurbit downy mildew has been reported on cucumber in southern New Jersey and Eastern PA. For more information on CDM control please click here.
- Bacterial leaf spot has been reported in pepper. More more information on BLS control please click here.
- Bacterial canker has been reported in tomato. For more information on diagnosing important tomato diseases please click here.
- Early blight has been reported on potato.
- Phytophthora blight has been reported on pepper. For more information please click here.
- Dickeya dianthicola has been reported in potato in Virginia and Massachusetts.
- The 2022/2023 Commercial Vegetable Production Recommendations Guide is available for free online or for sale in hardcopy form at many County offices.
- For a quick review on managing fungicide resistance development using tank mixes and fungicide rotations, and information on FRAC group 4, FRAC group 7, and FRAC group 3 and FRAC group 11 fungicides please click on hyperlinks.
Vegetable Disease Update: 07-02-22
Phytophthora blight control in pepper in 2023
Phytophthora blight typically develops in low-lying areas after a heavy rain and can spread quickly throughout the entire field. Fortunately, New Jersey has been really dry this summer, 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 does not mean it will not show up eventually. [Read more…]
2021 Phytophthora and Bacterial leaf spot bell pepper variety trial reports
Phytophthora blight caused by Phytophthora capsici is one of the most economically important diseases in pepper, tomato, and cucurbit production in New Jersey. The pathogen was first identified in a pepper field in southern New Jersey in 1971. Each year for the past three decades Rutgers has evaluated new bell pepper cultivars and breeding lines for their resistance to P. capsici in field trials at the Rutgers Agricultural Research and Extension Center (RAREC) near Bridgeton, New Jersey, and in some years, at research trials on farms near Vineland, NJ. The pathogen, an oomycete – ‘water mold’ is favored by warm weather and wet soils during the production season and can survive between seasons in the soil as oospores. Once found in a field, the pathogen can establish itself, and be very difficult to control even with the use of fungicides because of resistance development. Fortunately, in bell pepper, highly resistant or intermediate resistant cultivars to Phytophthora blight have been commercially-available for over 20 years now and have been used extensively by bell pepper growers throughout the state. Each year, Rutgers also evaluates each cultivar for their fruit quality characteristics (e.g., color, wall thickness, number of lobes, and development of ‘silvering’) to make sure they meet the needs of growers. Unfortunately, phytophthora resistant cultivars such as ‘Paladin’ which have been used extensively in southern New Jersey for the past 20 years appears to be breaking down. Because of increasing reports of bacterial leaf spot and copper resistance in recent years, bell peppers grown in NJ at some point will need to consider growing those cultivars with X10R resistance and phytophthora blight resistance. Importantly, for organic bell pepper growers, if you have not already done so, you should be evaluating these new lines to see if they meet your needs. The easiest way to mitigate both diseases are to start with genetic resistance. Below are the bell pepper variety and bacterial leaf spot reports for 2021.
Click to access Rutgers-Pepper-Phytophthora-Blight-Final-Report-2021.pdf
Click to access Rutgers-Bacterial-Leaf-Spot-Final-Report-2021.pdf
For more information on recommended bell pepper cultivars please visit the Pepper Section in the 2022/2023 Mid-Atlantic Commercial Vegetable Productions Recommendations Guide.
By: Andy Wyenandt and Wesley Kline
With rainfall, so comes Phytophthora and Pythium
Most of New Jersey has finally gotten rain and pop-up thunderstorms making conditions ideal for pathogens such as Phytophthora and Pythium on spring-seeded and transplanted crops. Unfortunately, Pythium 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. [Read more…]
Early-season Phytophthora blight and Rhizoctonia root rot control.
Phytophthora blight typically develops in low-lying areas after a heavy rain. 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 extended periods of dry weather works against Phytophthora development, it can lead to Rhizoctonia root rot issues in newly transplanted plugs, especially if those plugs remain on the dry side too long before watering. Symptoms of Rhizoctonia root rot appear as brown lesions at the base of the stem with those lesions eventually girdling the stem and extending about an inch above the soil surface. If transplants haven’t been treated the the cell flat prior to transplanting, apply a fungicide through the drip system soon after transplanting. [Read more…]
Phytophthora and pythium control during wet weather
Most of New Jersey has been plagued by heavy regular rains and pop-up thunderstorms making conditions ideal for pathogens such as Phytophthora and Pythium. Unfortunately, Pythium 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.
Control of Phytophthora blight and Pythium are extremely difficult (even with the use of fungicides) in the wet weather conditions. In the past few years a number of new fungicides, with new active ingredients, have become commercially-available for use 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. Mefenoxam, metalaxyl, Previcur Flex, 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 should offer some protection of the root system via drip. Ranman has protectant activity and thus will offer some root protection where it comes into contact with. Orondis Gold (oxathiapiprolin + mefenoxam, 49 +4) is the newest fungicide available with a new active ingredient in a new FRAC group. Additionally, in past research trials, mefenoxam, Orondis Gold, Presidio, Previcur Flex, Ranman, Revus and the phosphites in rotation and/or tank mixes have offered very good control of the fruit rot phase of phytophthora blight.
[Read more…]