Scouting wheat fields for rust is vital during this time as the weather conditions are favorable for the spread of foliar diseases in our area. Recognizing symptoms in a timely manner so that appropriate action can be taken will help prevent yield loss. Listed below are two types of rust that wheat producers should keep an eye out for.
Leaf rust is a destructive foliar disease of wheat and caused by the fungus Puccinia triticina. This disease is characterized by flaky, reddish-brown pustules that develop on the leaves and sheaths of the plant. Leaf rust can be found early in the growing season on the lower leaves but often appear in large numbers after the plant has flowered. With high humidity and temperatures ranging from 59 degrees F to 77 degrees F, it is the ideal environment for the development of leaf rust. Add in a few dry, windy days, and spores will easily spread from field to field.
Stripe rust, also known as yellow rust, is caused by the fungus Puccinia striiformis and is characterized by bright yellow to orange pustules arranged in rows on the leaves, leaf sheaths, glumes, and awns. Stripe rust develops at lower temperatures than other types of rust and favors cool, overcast and wet weather with ideal temperatures ranging between 50 degrees F to 60 degrees F. Spores from this fungus are dispersed through the air and can travel hundreds of miles.
There are several ways to prevent, manage, and treat rust in wheat. One prevention method is planting resistant varieties; however, there is a level of susceptibility involved as new races of the fungus can develop. It is also recommended that crop debris and volunteer plants be eradicated from the field as they can harbor inoculum over the winter. It is important to scout fields early in the season for rust so that timely fungicide applications can be made. Visit the 2021-2022 Georgia Wheat Production Guide for a list of rust resistant varieties and fungicides that can be used. https://grains.caes.uga.edu/content/dam/caes-subsite/grains/docs/wheat/Wheat-Production-Guide-2021.pdf