Rutgers Cooperative Extension
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Be sure to begin monitoring plantings for ECB feeding while they are still in the whorl stage. Consider treating when the number of infested plants in a 50 plant sample exceeds 12%. Feeding in the whorl stage will appear as numerous small holes (called “shot-hole”) on leaves, with damage present on consecutively younger leaves.
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The weather has been a double-edged sword of late throughout most of the mid-Atlantic region. The extremely hot weather with temperatures at or above 90 these past few days have been good for slowing disease development down. At those temperatures, its even too hot for pathogens to develop!
Unfortunately, the weather has also brought with it a lot of wind and rain these past few days and weeks. We all know what this leads to. Remember that bacteria need a wound or natural opening to enter a plant and cause an infection. The heavy winds and driving rains that beat up plants also help create the wounds that allow this to occur so its not unlikely to see an uptick in bacterial problems across a number of crops, such as in the case of bacterial leaf spot in tomato and pepper, after the weather we’ve had this past week.
Growers need to be proactive with copper applications and/or disinfestant applications prior to and/or after such events. Growers should also avoid working in fields when foliage is wet, if possible. This is extremely important if a bacterial problem is already present in the field!
The wet weather, along with the high humidity and prolonged leaf wetness also makes nice for many fungal pathogens, both leaf and soil-borne. Phytophthora blight in cucurbits, pepper, eggplant and tomato; Early blight in tomato; Alternaria and Anthracnose in cucurbits; and downy mildews just to name a few are favored by our current weather conditions, especially after temperatures cool down after todays weather front passes through the region.
During these conditions, all growers need to remain diligent and keep up with their protectant fungicide programs as long as field conditions allow and be proactive instead of reactive. After today, we get a few hours of dry weather before potential rains return on Thursday night into Friday.
Click to View | Download Report 6-23-15
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 New Jersey. An early season application of a protectant fungicide such as mancozeb (Dithane, Manzate, Penncozeb) or Bravo (chlorothalonil) as soon the field is accessible is suggested. Please be vigilant and keep a look out 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 chose 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.
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.
Cranberry beds are in full bloom. If insects have been effectively managed prior to bloom, we recommend no sprays at this time. A reminder: when bees are present, your only choices of insecticides are insect growth regulators (IGRs) such as Intrepid 2F or Bt products such as DiPel.
During bloom we recommend monitoring insect populations using pheromone traps. Pheromone traps should be used particularly to monitor activity of Sparganothis fruitworm and blackheaded fireworm, two key pests in New Jersey.
Sparganothis Larvae
Sparganothis Adult
Click to View | Download Report 6-19-15
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 New Jersey. An early season application of a protectant fungicide such as mancozeb (Dithane, Manzate, Penncozeb) or Bravo (chlorothalonil) as soon the field is accessible is suggested. Please be vigilant and keep a look out 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 chose 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.
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.
