As the summer heats up in New Jersey, the control of Phytophthora blight in cucurbit plantings can be extremely difficult (even with the use of fungicides) as hot, wet weather finally sets in. Mitigating losses to Phytophthora blight in cucurbit crops begins with long crop rotations, where recommendations suggest crop rotations longer than 5 years if possible. Other cultural practices include avoid planting in low areas of the field where water may persist after rain or overhead irrigation, rogueing out infected plants as soon as possible, cutting the plastic to help dry out the soil, proper weed control, and proper preventative fungicide programs.
May 24, 2024 Andy Wyenandt
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.
[Read more…]
May 23, 2024 Andy Wyenandt
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.
July 29, 2023 Andy Wyenandt
Vegetable Disease Update: 07-29-23
- Basil downy mildew has been reported in New Jersey.
- Rhizoctonia root rot has been reported in tomato and other vegetable crops.
- Phomopsis and Phytophthora fruit rot has been reported in eggplant.
- Collar rot has been reported on tomato. For more information please click here.
- Pythium cottony leak has been reported on pepper. For more information on controlling Pythium and Phytophthora please click here.
- Pepper anthracnose has been reported in southern New Jersey. For more information on controlling anthracnose fruit rot please click here.
- Cucurbit downy mildew has been reported on cucumber and cantaloupe in New Jersey with more being reported on the East Coast and Ontario, Canada. For more information on CDM control please click here.
- Blackleg has been reported on potato in New Jersey.
- There have been no reports of Late blight in potato or tomato in the region to date. Late blight has been reported in Ontario, Canada. To follow the progress of Late blight in the US please click here.
- Bacterial leaf spot has been reported in pepper. More more information on BLS control please click here. Rutgers is surveying tomato and pepper fields throughout the state this summer to help determine the makeup of the bacterial population and for copper resistance development.
- Powdery mildew has been reported in cucurbit crops. For more information on the control of CPM please click here.
- Southern blight has been reported on pepper.
- Bacterial canker has been reported in tomato. For more information on diagnosing important tomato diseases please click here.
- For information on diagnosing important diseases in pepper, tomato, and cucurbit crops please click on links.
- 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.
July 27, 2023 Andy Wyenandt
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.
[Read more…]
July 22, 2023 Andy Wyenandt
Vegetable Disease Update: 07-22-23
- Collar rot has been reported on tomato. For more information please click here.
- Pythium cottony leak has been reported on pepper. For more information on controlling Pythium and Phytophthora please click here.
- Pepper anthracnose has been reported in southern New Jersey. For more information on controlling anthracnose fruit rot please click here.
- Cucurbit downy mildew has been reported on cucumber and cantaloupe in southern New Jersey with more being reported on the East Coast and Ontario, Canada. For more information on CDM control please click here.
- Blackleg has been reported on potato in New Jersey.
- There have been no reports of Late blight in potato or tomato in the region to date. Late blight has been reported in Ontario, Canada. To follow the progress of Late blight in the US please click here.
- Bacterial leaf spot has been reported in pepper. More more information on BLS control please click here. Rutgers is surveying tomato and pepper fields throughout the state this summer to help determine the makeup of the bacterial population and for copper resistance development.
- Powdery mildew has been reported in cucurbit crops. For more information on the control of CPM please click here.
- Southern blight has been reported on pepper.
- Bacterial canker has been reported in tomato. For more information on diagnosing important tomato diseases please click here.
- For information on diagnosing important diseases in pepper, tomato, and cucurbit crops please click on links.
- 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.
