In a recent research article just published in Plant Disease, potato researchers in Maine and elsewhere examined 16 isolates associated with the Dickeya dianthicola outbreak in potato which began on the East Coast in 2015. This is a follow-up to an article published late last year looking into the origins of the outbreak. For more information on what was found in that study please click here. In their most recent study titled ‘Pangenomic analysis of Dickeya dianthicola strains related to the outbreak of Blackleg and soft rot of potato in the USA‘ eight distinct clades were distinguished based on phylogenomic analysis of 32 isolates with three clades (as previously reported) causing the outbreak on the East Coast in 2015, with the majority of isolates belonging to Clade I. Clade I strains were determined to be unique and homogeneous and the authors suggested they were a recent incursion from alternative hosts or environmental sources. The authors state the genomes of D. dianthicola isolates in Clade I possessed nearly identical genomics to that of isolate ME23 (previously identified in ME in 2015), and that each outbreak of the disease is typically caused by one predominant genotype due in part to contamination and spread of that genotype in one or a few widely used potato sources. The authors state that in the US, seed potatoes from a small number of sources in the northeast quarter of the US appeared to be important during the early stages of the outbreak, although, they (the authors) do not have enough evidence to explain how Clade I emerged and caused the outbreak. The authors suggested that while Clade I was predominant in causing the outbreak, other clades should not be ignored since these are present in the environment and additional outbreaks could occur since D. dianthicola has a wide host range and, clades currently not detected in the US could enter through trade in ornamental plants or seed.
July 12, 2021 Andy Wyenandt
Vegetable Disease Update – 7/12/21
- Pepper anthracnose has been reported in southern New Jersey. For more information on preparing for pepper anthracnose please click here.
- Cucurbit downy mildew has been reported on cucumber (6/16/21) and cantaloupe (6/22/21) in southern New Jersey. There have been no reports of CDM on other cucurbit hosts in the region to date. For more information on CDM and its control please click here. To track the progress of CDM please visit the CDM forecasting website.
- No reports of Late blight in the region. To track the progress of Late blight in the US please click here.
- Cucurbit powdery mildew has been reported on summer squash, butternut, and spaghetti squash as we are now headed into mid-summer. Please scout fields on a regular basis and initiate a preventative fungicide program if you haven’t already done so. For more information on CPM control please click here.
- Bacterial leaf spot (BLS) continues to be reported on bell and non-bell peppers in southern New Jersey. Rainfall is expected later in the week making conditions ideal for the spread of BLS. For more information on our continuing survey for BLS and copper resistance detection in tomato and pepper please click here.
- The 2020/2021 Commercial Vegetable Production Recommendations Guide is available for free online.
- 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 6, 2021 Andy Wyenandt
Vegetable Disease Update – 7/6/21
- Cucurbit downy mildew has been reported on cucumber (6/16/21) and cantaloupe (6/22/21) in southern New Jersey. There have been no reports of CDM on other cucurbit hosts in the region to date. For more information on CDM and its control please click here. To track the progress of CDM please visit the CDM forecasting website.
- No reports of Late blight in the region. To track the progress of Late blight in the US please click here.
- Cucurbit powdery mildew has been reported on summer squash, butternut, and spaghetti squash as we are now headed into mid-summer. Please scout fields on a regular basis and initiate a preventative fungicide program if you haven’t already done so. For more information on CPM control please click here.
- Bacterial leaf spot (BLS) continues to be reported on bell and non-bell peppers in southern New Jersey. Rainfall is expected later in the week making conditions ideal for the spread of BLS. For more information on our continuing survey for BLS and copper resistance detection in tomato and pepper please click here.
- Now is the time to start thinking about pepper anthracnose control, especially on farms or fields with a history of the disease. For more information on preparing for pepper anthracnose please click here.
- Southern blight has been reported on tomato in central New Jersey.
- The 2020/2021 Commercial Vegetable Production Recommendations Guide is available for free online.
- 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.
June 29, 2021 Andy Wyenandt
Vegetable Disease Update – 6/29/21
- Cucurbit downy mildew has been reported on cucumber (6/16/21) and cantaloupe (6/22/21) in southern New Jersey. For more information on CDM and its control please click here. To track the progress of CDM please visit the CDM forecasting website.
- No reports of Late blight in the region. To track the progress of Late blight in the US please click here.
- Bacterial leaf spot (BLS) has been reported on bell and non-bell peppers in southern New Jersey.
- Southern blight has been reported on tomato in central New Jersey.
- Northern corn leaf blight has been confirmed in sweet corn last week in southern New Jersey.
- Basil downy mildew has been reported from multiple locations in southern New Jersey. All basil growers are encouraged to scout their plantings on a daily basis. For more information on controlling BDM please click here. To follow the progress of BDM in the US please click here.
- Rhizoctonia and Pythium root rot have been reported in pepper. For a review of identifying and controlling root rots please click here.
- The 2020/2021 Commercial Vegetable Production Recommendations Guide is available for free online.
- 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.
June 26, 2021 Andy Wyenandt
NEWA Disease and Insect Forecasting System
The NEWA (Network for Environment and Weather Applications) website managed by the New York state Integrated Pest Management (IPM) program can be found at http://newa.cornell.edu/. The website is easy to use and offers weather data as well as insect and disease forecasting (e.g., P-days for Early blight and BlightCast for Late Blight in potato, and Tom-Cast DSV’s for Early blight, Septoria leaf spot and Anthracnose fruit rot in tomatoes. Just click on the map and scroll down to New Jersey and chose a weather station within the closest proximity to your operation. Once you choose a location a new webpage will appear with the different forecasting options to choose from. Clicking on the potato early blight will automatically generate daily and accumulative P-day values for you for that location. Remember once 300 P-days are accumulated, spray programs for early blight control should be initiated. Clicking on either tomato or potato Late blight will bring up a table which will provide daily rainfall, average temperature, hours above 90% RH and daily and accumulative DSV values for that location. One important thing to remember for the disease forecasting is to track the accumulation of DSV or P-day values based on when you transplanted tomatoes or when potatoes emerged on your farm.
To track the progress of Late blight in the US you may also visit http://usablight.org/
June 23, 2021 Andy Wyenandt
Vegetable Disease Update – 6/22/21
- Cucurbit downy mildew has been reported on cucumber (6/16/21) and cantaloupe (6/22/21) in southern New Jersey. For more information on CDM and its control please click here. To track the progress of CDM please visit the CDM forecasting website.
- No reports of Late blight in the region. To track the progress of Late blight in the US please click here.
- Bacterial leaf spot (BLS) has been reported on ‘Paladin’ bell pepper in southern New Jersey which has no resistance to BLS.
- Rhizoctonia root rot has been found in sugar beet in New Jersey.
- Northern corn leaf blight has been confirmed in sweet corn in southern New Jersey.
- Basil downy mildew has been reported from multiple locations in southern New Jersey. All basil growers are encouraged to scout their plantings on a daily basis. For more information on controlling BDM please click here. To follow the progress of BDM in the US please click here.
- Rhizoctonia and Pythium root rot have been reported in pepper. For a review of identifying and controlling root rots please click here.
- With the on and off again heavy rains we have been getting, along with warmer weather, all growers should consider applying at-transplanting fungicides for root rot control. Please click here to see these articles.
- The 2020/2021 Commercial Vegetable Production Recommendations Guide is available for free online! With many county offices running reduced hours or being closed this is the easiest way to obtain the newest recommendations.
- 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.
