Andy Wyenandt

This is an archive of Dr. Wyenandt's posts on the Plant and Pest Advisory.

Vegetable Disease Update – 6/29/21

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/

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.

Cucurbit Downy Mildew Alert – Cantaloupe – 6/22/21

Cucurbit downy mildew has been confirmed on cantaloupe in southern New Jersey. This is the first report of CDM on cantaloupe and the second this growing season. CDM was confirmed on cucumber on 6/16/21. All cucumber and cantaloupe growers should scout on a daily basis and initiate a preventative fungicide program. CDM has also been confirmed on cucumber in Ontario, Canada this week. 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 Alert – Cucumber – 6/16/21

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 has also been confirmed on cucumber in Ontario, Canada this week. 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.

Important resources for pepper disease control

Pepper production is in full swing in New Jersey and the mid-Atlantic region. Below are links to useful resources for the identification and management of important pepper diseases.

Early-season Phytophthora and Pythium control

Preparing for pepper anthracnose

Phytophthora-tolerant and -resistant bell pepper variety trial reports

Survey continuing for bacterial leaf spot and copper resistance in 2021 growing season