In 2004, cucurbit downy mildew re-emerged in the US with a vengeance causing significant losses in cucurbit production. In most years prior to this, concern for CDM control was minimal, since the pathogen arrived late in the growing season (in more northern regions), or the pathogen caused little damage, or never appeared. After 2004, with significant losses at stake, and with very few fungicides labeled for its proper control, CDM became a serious threat to cucurbit production. Importantly, at the time, cucumber varieties with very good levels of CDM resistance were no longer resistant, suggesting a major shift in the pathogen population. Research done over the past 19 years has led to a better understanding of the pathogen. Recent research has determined that the CDM falls into two separate clades: Clade I and Clade II. [Read more…]
Cucurbit Downy Mildew Alert – Pumpkin and Summer Squash – 8/21/24
Cucurbit downy mildew (CDM) has been reported on pumpkin in central New Jersey (8/18) and on yellow summer squash and zucchini in southern New Jersey. These are the first reports of CDM on pumpkin and summer squash in the state and region this growing season. All cucurbit growers should scout on a daily basis and initiate a preventative CDM fungicide program immediately. CDM was confirmed on cucumber in New Jersey on 6/19/24. Remember, some CDM isolates fall into Clade I which predominately infect watermelon, pumpkin, and squash, where CDM isolates in Clade II predominately infect cucumber and cantaloupe.
For more information on CDM, the clades, and CDM control please click here.
Cucurbit Downy Mildew Alert – Cucumber – 6/19/24
Cucurbit downy mildew has been confirmed on cucumber in Salem County in southern New Jersey. This is the first report of CDM in the state and region this growing season. All cucumber and cantaloupe growers should scout on a daily basis and initiate a preventative fungicide program immediately. All other cucurbit plantings need to be scouted on a regular basis. CDM was last confirmed on cucumber in central North Carolina on 6/4/24. Remember, some CDM isolates fall into Clade I which predominately infect watermelon, pumpkin, and squash, where CDM isolates in Clade II predominately infect cucumber and cantaloupe.
For more information on CDM, the clades, and CDM control please click here.
Cucurbit downy mildew sporulating on the underside of an infected cucumber leaf.
Preparing for cucurbit downy mildew in 2024
In 2004, cucurbit downy mildew re-emerged in the US with a vengeance causing significant losses in cucurbit production. In most years prior to this, concern for CDM control was minimal, since the pathogen arrived late in the growing season (in more northern regions), or the pathogen caused little damage, or never appeared. After 2004, with significant losses at stake, and with very few fungicides labeled for its proper control, CDM became a serious threat to cucurbit production. Importantly, at the time, cucumber varieties with very good levels of CDM resistance were no longer resistant, suggesting a major shift in the pathogen population. Research done over the past 19 years has led to a better understanding of the pathogen. Recent research has determined that the CDM falls into two separate clades: Clade I and Clade II. [Read more…]
Vegetable Disease Update: 08-24-23
- Cucurbit downy mildew has been reported on pumpkin, butternut squash, spaghetti squash, cucumber, and cantaloupe in New Jersey. For more information on CDM control please click here.
- Pepper anthracnose is being reported in New Jersey. For more information on controlling anthracnose fruit rot please click here.
- Basil downy mildew has been reported in New Jersey.
- There have been no reports of Late blight in potato or tomato in the region to date. 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.
- 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.
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.
