The plants in the picture below were from one of the stripe rust hot spots found in a Lonoke County wheat field in December. The plants were dug up on January 9 and placed in a growth chamber for 2 weeks at a cool temperature favorable for stripe rust. The lower leaves that had stripe rust in December are dead or dying from the combination of rust and cold injury, but several of the upper leaves have fresh stripe rust lesions. The upper leaves with lesions were infected in the field, but the rust did not show up until plants were at a favorable temperature for several days. As the weather gets warmer, the same phenomenon is happening in wheat fields across the state, and additional leaves get infected when dew is on the plants for more than 6 hours.
Additional fields with stripe rust hot spots are being reported, and the time for early-season management is approaching quickly, especially in south Arkansas. Tank-mixing a labeled fungicide with a spring herbicide application for broadleaf weeds or ryegrass is the most cost-effective means of dealing with early stripe rust. All fungicides labeled for wheat will stop the epidemic for several weeks, so choose the least expensive option, but be sure the fungicide and herbicide are compatible as a tank mix. The best time to scout for hot spots is shortly before the planned herbicide application because this will allow more time for the rust to develop on upper leaves and make it easier to find. All wheat varieties are more or less susceptible to stripe rust at this time, and most develop adult-plant resistance as they mature. However, the adult-plant resistance can be overcome by new races of the stripe rust fungus, so it is important to control stripe rust early before it really gets going as it did in 2000.