Agronomic Crop Disease Update – May 13, 2011

Bob Mulrooney, Extension Plant Pathologist; bobmul@udel.edu

Barley
Powdery mildew on ‘Thoroughbred’ is the most common disease at the present time. Fields with the top two leaves with mildew will have some yield reduction. After looking at the variety trials in Sussex County on Tuesday I could also find small amounts of leaf rust, barley scald and the spot form of net blotch. None of these should impact yield.

Wheat
Wheat is looking very good at the present time. There is very little disease present. A few unsprayed varieties have some powdery mildew that is confined to the lower leaves and leaf sheaths. A small amount of leaf rust was also spotted on one unsprayed variety on the lower leaves. Most of the wheat that I saw has flowered and with the dry weather in most of the southern parts of the state, it looks like head scab should not be a problem. In the northern areas of the state if we get showers this weekend we may have some opportunity for infection if wheat is flowering.

Barley scald

 

 

Barley scald

Soybeans and Soybean Cyst Nematode
It is still not too late to check for soybean cyst nematode especially if susceptible soybeans are going to be planted. Soil test bags with the submission form can be purchased at the Extension offices. If you need results quickly, test results can be sent via FAX or email if you provide the number or email address on the Nematode Assay Information Sheet. This information sheet can be found on the web at the Plant Clinic Website http://ag.udel.edu/extension/pdc/index.htm .