There has been little change in European corn borer (ECB) catches over the past week. We would have expected some increase throughout the state, but prolonged wet weather has likely slowed their activity. The highest catches remain in southern Hunterdon County (see map at left), although there have been low, but steady catches elsewhere, including northern Cumberland and central Morris counties. Feeding continues to be very limited, but should increase with drier conditions later this week. Check 5 plants each in 10 random locations for a 50 plant sample. Look for “shot-hole” injury (see photo at right), and consider treating when the number of infested plants in a 50 plant sample exceeds 12%. [Read more…]
Archives for May 2017
Late blight reported on potato in North Carolina
Late blight was reported in potato being grown in northern North Carolina on Monday May 29th. This is the first report of Late blight this growing season outside of Florida. No late blight has been reported in the mid-Atlantic region to date. All potato growers are encouraged to scout their fields on a regular basis. The latest Potato|Tomato Disease Forecasting Report can be found here.
Potato | Tomato Disease Forecast 6-2-17
Click to View | Download Report 6-2-17
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.
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
Weeds off to a Slow Start
Despite a quick start to the spring, soil temperatures remain low across the much of the state. Average soil temperatures (3-inch depth) have been hanging around the mid 60s in central NJ and many warm-season weeds such as crabgrass have hardly developed despite germinating over 6 weeks ago. This crabgrass at our research facility has not […]
Weeds off to a Slow Start
Despite a quick start to the spring, soil temperatures remain low across the much of the state. Average soil temperatures (3-inch depth) have been hanging around the mid 60s in central NJ and many warm-season weeds such as crabgrass have hardly developed despite germinating over 6 weeks ago. This crabgrass at our research facility has not […]
Weeds off to a Slow Start
Despite a quick start to the spring, soil temperatures remain low across the much of the state. Average soil temperatures (3-inch depth) have been hanging around the mid 60s in central NJ and many warm-season weeds such as crabgrass have hardly developed despite germinating over 6 weeks ago. This crabgrass at our research facility has not […]