Archives for May 2014

May 5, 2014

Potato Disease Forecasting Report 5-5-14

Potato Disease Forecasting Report 5-5-14 – Click to Download

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.

Filed Under: Disease Forecasting
May 5, 2014

Tomato Disease Forecasting Report 5-5-14

5-5-14 Tomato Report – Click to Download

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.

Filed Under: Disease Forecasting
May 2, 2014

Free, Updated Agronomic Crops Weed Control Guides

Available from the UD-REC website are weed management guides for assistance in weed control in corn, soybeans, or forages.
http://extension.udel.edu/ag/weed-science/weed-management-guides/

There is a separate guide for each commodity. The first half of the corn and soybean guides deal with soil-applied herbicides and the second half is for postemergence herbicides. These guides have pre-mixes and what is in the pre-mix, expanded weed control tables, information on application timing, comments for each of the herbicides, and much more. The forage guides cover alfalfa as well as grass forages.

Filed Under: Commercial Ag Updates
May 2, 2014

Herbicide Classification Chart Available

Working with the Delaware Soybean Board and the United Soybean Board, a herbicide classification chart is available at:
http://extension.udel.edu/ag/weed-science/weed-management-guides/

This chart groups herbicides by mode of action and site group numbers that are printed on containers and labels. The chart is designed to help diversify herbicide use by rotating effective herbicides with different sites of action to delay the development of herbicide resistance. The chart provides the number of resistant weed species in the US to each site of action, which highlight those herbicides for which we already have wide-spread resistance.

Filed Under: Commercial Ag Updates
May 2, 2014

No-Till Soybean Burndown Considerations

Due to the weather, a number of no-till soybean fields have not received a burndown treatment yet. As a result, many are asking about options for control. First a number of considerations:

2,4-D ester: Rate of 2,4-D may need to be adjusted. Most 2,4-D brands require a 4 week delay between application of 1 qt and planting soybeans. Rates less than 1 qt/A does not provide the same level of horseweed control. The interval between application differs with 2,4-D rates and brands. Be sure to read the label of the brand you intend to use.

Kixor products: These products have good activity on glyphosate and ALS resistant horseweed, but they have a number of restrictions due to crop safety: [Read more…]

Filed Under: Commercial Ag Updates
May 1, 2014

Strawberry Fruit Rots

Anthracnose fruit rot of strawberry

Anthracnose Fruit Rot of Strawberry

Fruit rots in strawberry can cause significant losses if not recognized early and controlled. The use of good cultural practices such as: keeping fields weed-free and promoting good drainage; long crop rotations, and preventative fungicide applications are critical.

Pathogens such as anthracnose, gray mold (Botrytis), and leather rot can become systemic problems in strawberry plantings once established. All three fungal diseases are soil-borne and once in fields can be difficult to manage over the lifetime of the planting.

The use of mulch (matted rows) to prevent/reduce soil splashing and keeping fruit from coming into direct contact with the soil surface can be beneficial in organic production systems where conventional fungicides cannot be used. Use of long crop rotations and staying away from areas of the farm with known instances of any of these pathogens is also important. Remember that same species of Colletotrichum that causes fruit rot in pepper and other crops can also infect strawberry.

[Read more…]

Filed Under: Vegetable Crops Tagged With: