URGENT: Wheat Stripe Rust Alert!

Wheat stripe rust has been found on a farm in southern North Carolina. It is unusual for us to see this disease. However, stripe rust is a serious threat to our wheat crop. It can do a lot of damage very quickly and should be controlled.


Stripe rust often gives a yellow look to the field. So you may look out across a green field of wheat and see a small area that looks yellow. Looking closer the leaves will have small yellowish rust pustules usually in a line. That is why it's called stripe rust! Pictures are left and below. .


The following varieties are the most likely to be infected and are the ones growers should check:


C9436, DG Shirley, NC Cape Fear, NC Neuse, NC Yadkin, P26R12, SS520, SS560, USG3209, USG3592, USG3665, and SS8404


If stripe rust is found it should be sprayed as soon as possible. Two possible products to consider are Folicur (Tebuconazole) and Prosaro. Both products can be applied up to 30 days before harvest.

 

The following excerpt of information comes from the North Carolina Guide To Leaf, Stem, and Stripe Rust. For the complete guide, please contact Christina Cowger USDA-ARS, Department of Plant Pathology (919) 513-7388 Christina.Cowger@ars.usda.gov OR  Randy Weisz Department of Crop Science (919) 515-5824 randy_weisz@ncsu.edu

Rust diseases are among the most widespread  and economically important diseases of cereal crops worldwide. Three distinct diseases, leaf rust, stripe rust and stem rust, occur on wheat and barley in North America.The fungi that cause these diseases are notorious for their ability to increase rapidly and overcome the resistance of wheat or barley varieties. The potential yield loss caused by these diseases depends on host susceptibility and weather conditions, but the loss also is influenced by the timing and severity of disease outbreaks relative to crop growth stage. The greatest yield losses occur when one or more of these diseases occur before the heading stage of development. Early detection and proper identification are critical  to in-season disease management and future variety selection. 

Stem rust 
Parts of plant infected: Commonly affects stems, leaf sheaths, and leaf blades; occasionally will affect parts of the head 

Shape and distribution of lesions: Oval-shaped or elongated blister-like lesions scattered on affected tissues, lesions visible on both sides of leaf 

Lesion color: Orange-red

Degree of damage: Tearing of outer layers of plant tissue that is visible without magnification 

Leaf rust 
Parts of plant infected: Commonly occurs on leaf blades, but may also affect leaf sheaths; infections of stems and heads are rare 

Shape and distribution of lesions: Round or slightly elongated blister-like lesions scattered on affected tissues 

Lesion color: Brown 

Degree of damage: Tearing of outer layers of plant tissue rare, visible with magnification  

Stripe rust
Parts of plant infected: Commonly affects leaf blades, occasionally observed on heads when disease is very severe; infection of leaf sheaths or
stems is rare

Shape and distribution of lesions: Small, round,blister-like lesions that merge to form stripes

Lesion color: Yellow-orange

Degree of damage: No tearing of outer layers of plant tissue

Identification of Rust Diseases
Differentiating the rust diseases can be difficult, but with practice they can be reliably identified. Begin by considering broad characteristics such as which plant parts are affected or arrangement of the blister-like lesions on plants.These characteristics will often separate one or more of these
diseases quickly. Continue by examining less obvious characteristics including lesion size, shape, and color to either confirm the diagnosis or separate the more similar diseases. For example,stripe rust is the only one of these diseases to have the blister-like lesions organized into stripes on the leaves (left). If the lesions are scattered on the affected plant parts, both stem rust and leaf rust are a possibility and additionalcharacteristics must be considered. Leaf rust typically causes small, round lesions on the leaf blades and leaf sheaths. In comparison, stem rust causes oval or elongated lesions and is capable of infecting nearly all aboveground parts of the plant, most notably the true stems

All three diseases have unique interactions with common varieties of wheat and barley.These interactions can modify the disease symptoms resulting in reduced lesion size and varying amounts of yellow or tan tissue surrounding the lesions (Figure 3). Becoming familiar with the range of
possible symptoms for these diseases will improve the accuracy of the diagnosis and the management of these economically important diseases.


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