Wheat Disease Identification

April 17, 2012 in Uncategorized

Below are pictures of wheat diseases that are found in Delaware. The barley yellow dwarf pictures are from this year, all the other photos are from 2011.  Click on any photo to make it larger.

Wheat infected by Barley Yellow Dwarf Virus.  Note the yellow and red discoloration at the tip of affected leaves.  Photo by P. Sylvester.
Wheat infected by Barley Yellow Dwarf Virus.  Typically occurs in patches within a field. Caused by feeding of aphids which spread the disease.  Photo by P. Sylvester

Leaf Rust on Wheat.  Photo by P. Sylvester.

Wheat heads with symptoms of Fusarium Head Blight (scab).  Photo by P. Sylvester

Wheat heads with symptoms of Fusarium Head Blight (scab).  Photo by P. Sylvester.

Wheat heads with symptoms of Fusarium Head Blight (scab).  Photo by P. Sylvester.

Septoria tritici blotch (speckled leaf blotch) on wheat.  Note the dark reproductive structures produced by the fungus in the middle of the tan lesions.  Photo by P. Sylvester
Tan Spot on Wheat.  Note the tan lesions with a dark center surrounded by a yellow margin.  Photo by P. Sylvester.

Powdery Mildew on Barley.  Photo by P. Sylvester.

Phillip Sylvester, Extension Agriculture Agent, UD, Kent County.

Wheat Diseases

May 31, 2011 in Uncategorized

Disease resistance varies among commercial varieties and now is a good time to evaluate varieties to help make selections for next year.  While yield is the most important aspect of a variety, disease resistance or tolerance is another tool growers should keep in mind while making selections.  Knowing what diseases are in your field is important.  Below is an article from Bob Mulrooney, Extension Plant Pathologist, UD discussing diseases found in the small grains trial near Sandtown, DE.

The wheat in the Kent County variety trial has tan spot moving in rapidly on some varieties. Most of the varieties are in the watery ripe stage of development and will not likely be adversely affected. Leaf rust was easily seen on a public variety ‘Rumor’. Powdery mildew in general was low in most varieties but was in the upper canopy on SS8302, Milton, Bravo, and USG3770. There is a low level of scab in the trial as well. If scab is going to appear it should be evident now or very soon depending on location. Low levels of scab (less than 1% of the heads infected and most of the infected heads were only partially infected) were present in 8 out of 45 varieties (around 18%).There is some sort of physiological spotting that could look like a disease but is probably a resistance reaction by the variety in response to a fungal infection. This spotting was evident on the following varieties at this Sandtown location: Merl, Sunburst,USG3665, USG3409, USG3251, and Grow Mark FS627.

Photo 1. Fusarium Head Blight in Winter Wheat (Photo by Phillip Sylvester)

Photo 2. Fusarium Head Blight in Winter Wheat (Photo by Phillip Sylvester)

Photo 3. Fusarium Head Blight in Winter Wheat (Photo by Phillip Sylvester)

Article by Bob Mulrooney, Extension Plant Pathologist, UD in Weekly Crop Update Volume 19, Issue 10 – May 27, 2011 http://agdev.anr.udel.edu/weeklycropupdate/ Photographs by Phillip Sylvester, Extension Agent, Agriculture, UD, Kent County.