Archives for August 2013

August 2, 2013

Tough Year for Summer Patch Disease

By Jim Murphy

Severe summer patch disease on hard fesuce at Hort Farm No. 2 in July 2013.

Severe summer patch disease on hard fesuce at
Hort Farm No. 2 in July 2013.

I have seen as much disease damage on turf this summer as any year since I began living and working in New Jersey. The weather has been ideal for summer patch and brown patch diseases. Summer patch disease is caused by a root infecting pathogen, Magnaporthe poae. I have observed more damage on hard fescue turf than Kentucky bluegrass. This is likely due to the fact that many people are growing varieties of Kentucky bluegrass with better tolerance of the disease than was the case 20 or more years ago.

There are some cultural techniques that can reduce the severity of summer patch disease including:

  1. Fertilize at no more than 1 lbs. of N per 1,000 sq. ft. per application and 2 lbs. annually)
  2. Use an acidifying N source (for example, ammonium sulfate)
  3. Reduce soil compaction (aerify)
  4. Maintain a slightly acidic soil pH (around 6.0); do NOT lime until pH reaches mid to low 5′s and do NOT attempt to increase the soil pH much above 6.0
  5. Use seed mixtures (rather than blends) that include tolerant species when seeding hard fescue or Kentucky bluegrass as a major component of the turf. Hard fescue and Kentucky bluegrass (depends on the variety) are sensitive to summer patch.
  6. Seed with tolerant species which includes tall fescues, perennial ryegrass, and Chewings fescue. Chewings fescue can be damaged by summer patch disease but it is more tolerant than hard fescue as you can see in the image below.
A range of hard fescue entries in an evaluation trial that were severely damaged by summer patch disease. Disease stops at the plot edge with Chewings fescue (line defined by plot signs at field day).

A range of hard fescue entries in an evaluation trial that were severely damaged by summer patch disease. Disease stops at the plot edge with Chewings fescue (line defined by plot signs at field day).

Links below open PowerPoints on summer patch disease prepared by Dr. Bruce Clarke.

Getting to the Root of the Problem; Biology and Management of Patch Diseases

BMPs for the Control of Summer Patch on Annual Bluegrass Turf

Source: Read More on the Rutgers Turf Blog

Filed Under: Turf
August 2, 2013

ACGA Preview: Research in Cranberry Entomology

Join us August 15 for the ACGA Summer Field Day to visit research bogs and discuss results.

Insecticide Trials against Sparganothis Fruitworm and Spotted Fireworm

We are currently conducting experiments to compare the efficacy of various insecticides (Delegate, Altacor, Intrepid, Lorsban, Imidan, and 2 unregistered insecticides) against Sparganothis fruitworm and spotted fireworm larvae in cranberries. [Read more…]

Filed Under: Cranberry
August 2, 2013

Controlling fungal leaf blights of Carrot

Powdery mildew, Alternaria and Cercospora are three important fungal foliar pathogens that can cause early defoliation in carrots, thus reducing yields and making harvest difficult. Each pathogen produces distinct symptoms. [Read more…]

Filed Under: Vegetable Crops Tagged With: , ,
August 2, 2013

Vegetable Disease Briefs – 8/2/13

Although conditions have been favorable, No Late blight has been reported in New Jersey this past week.

Basil

Downy mildew remains active – All basil growers should scout on a daily basis and should add a labeled downy mildew specific fungicide to their weekly fungicide program. Phosphite fungicides (FRAC code 33), such as Prophyt, K-Phite, and Rampart have shown the best efficacy in trials at RAREC. Actinovate (OMRI- approved) is also labeled for downy mildew control. Please remember, all abandoned basil fields should be worked under immediately after last harvest to kill the foliage! Abandoned fields left unattended after use will only serve as a source of inoculum for other fields. [Read more…]

Filed Under: Vegetable Crops
August 1, 2013

Tomato Disease Forecasting Report 8-2-13

8-2-13 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
August 1, 2013

Potato Disease Forecasting Report 8-2-13

Potato Disease Forecasting Report 8-2-13 – 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