- Cucurbit downy mildew has been confirmed on cucumber in New Jersey. To date, cucurbit downy mildew has been reported on cucumber and melon in the mid-Atlantic region. All cucumber growers need to add a downy mildew-specific fungicide to their weekly fungicide programs. All cucurbit growers need to scout on a regular basis.
- Dickeya dianthicola was confirmed in New Jersey on ‘Dark Red Chieftain’ originating from New Brunswick, Canada this past week. This is the third report of Dickeya on seed originating from Canada this summer. ‘Yukon Gold’ and ‘Reba’ from New Brunswick, Canada have also tested positive. In total, Dickeya dianthicola has been confirmed in 16 states to date. All potato growers are encouraged to scout fields and report any suspect plants/tubers. The best method for keeping your potato operation Dickeya-free is to adopt your own 0% Dickeya-tolerance policy.
- Pepper anthracnose is being reported in southern New Jersey.
- Cucurbit powdery mildew is active on all cucurbit crops.
- There have been no new reports of Late blight this this past week.
Archives for September 2016
September 6, 2016 Andy Wyenandt
Vegetable Disease Briefs – 9/6/16
September 1, 2016 A.Wyenandt, W.Kline, and J.Ingerson-Mahar
Potato | Tomato Disease Forecast 9-2-16
Click to View | Download Report 9-2-16
Potato Disease Forecasting Report
We will be tracking DSVs for Late blight development and calculating P-days for initiating the first early blight fungicide application.
The first late blight fungicide application is recommended once 18 DSVs accumulate from green row. Green row typically occurs around the first week in May in southern NJ. An early season application of a protectant fungicide such as mancozeb (Dithane, Manzate, Penncozeb) or Bravo (chlorothalonil) as soon as the field is accessible is suggested. Please be vigilant and keep a lookout for suspect late blight infections on young plants. No late blight has been reported in our region to date.
Remember the threshold for P-days is 300! Once 300 P-days is reached for your location, early blight fungicide applications should be initiated. Growers who are interested in using this model should choose the location above that is closest in proximity to their farming operation and should regularly check the Cornell NEWA website (http://newa.cornell.edu/) where this information is compiled from. Click on Pests Forecasts from the menu, select your weather station, and click on tomato diseases, set accumulation start date, and a table of daily and total DSVs will be generated.
Tomato Disease Forecasting Report
Disease severity values (DSVs) for early blight, septoria leaf spot, and tomato anthracnose development are determined daily based on leaf wetness (due to rainfall, dew) and air temperature.
On a daily basis DSV values can range from 0 to 4 where 0 = no chance for disease development to 4 = high chance for disease development.
DSVs are accumulated during the production season.Fungicide applications are based on an individually determined DSV threshold. The first fungicide application for the control of these three diseases is not warranted until 35 DSVs have accumulated from your transplanting date. After that, growers can base fungicide applications on different DSV thresholds.
Reports generated by Ryan Tirrell
Rutgers, The State University of New Jersey
