Cucurbit powdery mildew (CPM), caused by Podosphaera xanthii, is one the most important diseases of cucurbit crops throughout the world. The pathogen is an obligate parasite, just like cucurbit downy mildew, meaning it needs a living host in order to survive. In northern regions that have a killing frost in the fall the pathogen will die out when the crop freezes. Not being able to overwinter, the pathogen must be re-introduced each spring or summer in the mid-Atlantic region. The pathogen accomplishes this by re-infecting cucurbit crops in the spring as they are planted up the east coast starting in Florida, then the Carolina’s, Virginia, and so forth. By late May, as soon as cucurbit crops begin to germinate in the mid-Atlantic region, the potential threat for potential powdery mildew infections begin. [Read more…]
Cucurbit Downy Mildew Alert – Cucumber – 6/11/22
Cucurbit downy mildew has been confirmed on cucumber 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. CDM was last confirmed on June 1 on cucumber in central North Carolina and on watermelon on June 9 in south central Georgia. Remember, some CDM isolates fall into Clade I which predominately infect watermelon, pumpkin, and squash, where other 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 important fungal diseases in Asparagus during the summer.
Asparagus growers should consider scouting their fields during the summer months for foliar disease development. Important pathogens that growers need to scout for on a regular basis include Purple spot, Cercospora, and Rust. [Read more…]
Vegetable Disease Update: 5-27-22
- Neopestalalotiopsis on strawberry has been reported. Please click here to see the report from Penn State University Extension.
- Dickeya dianthicola has been reported in potato in Virginia.
- Botrytis and Anthracnose fruit rot is being reported in strawberry. For more information on controlling these two important diseases please click here.
- Cucurbit downy mildew has been reported on cucumber only as far north as Bamberg, County, GA (south central part of the state). To follow CDM reports in the U.S. please click here. Recent research has shown that oospores of the pathogen can overwinter in the southern US (North Carolina), but overwintering oospores were unable to germinate and cause infection the following spring. For more information please click here.
- Suncald has been reported in newly transplanted pepper fields. For more information please click here.
- Timber rot has been reported in tomato. For more information please click here.
- White rust has been reported in spinach.
- 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.
Anthracnose and Botrytis Control in Strawberries for 2022
Dr. Mengjun Hu, University of Maryland, and Kathy Demchak, Penn State University, have written an extensive article on effective strategies for Botrytis and Anthracnose fruit rot control for the 2022 season.
Managing gray mold (Botrytis) on strawberries is increasingly challenging because of fungicide resistance development, plus a new Botrytis species that is less susceptible to fungicides is becoming common in the mid-Atlantic region. Resistance to certain fungicides is also a problem in management of anthracnose fruit rot. This article describes disease management strategies designed to slow further resistance development, while also providing specifics for managing our two most common fruit rots.
The rest of the article can be accessed and downloaded as a PDF file by clicking on the following link: Botrytis and Anthracnose Mgt Strawberries final.
Anthracnose and Botrytis Control in Strawberries for 2022
Dr. Mengjun Hu, University of Maryland, and Kathy Demchak, Penn State University, have written an extensive article on effective strategies for Botrytis and Anthracnose fruit rot control for the 2022 season.
Managing gray mold (Botrytis) on strawberries is increasingly challenging because of fungicide resistance development, plus a new Botrytis species that is less susceptible to fungicides is becoming common in the mid-Atlantic region. Resistance to certain fungicides is also a problem in management of anthracnose fruit rot. This article describes disease management strategies designed to slow further resistance development, while also providing specifics for managing our two most common fruit rots.
The rest of the article can be accessed and downloaded as a PDF file by clicking on the following link: Botrytis and Anthracnose Mgt Strawberries final.
