Good Growing Conditions Cause Problems in Winter Wheat

By Bruce Fickenscher

Extension Agent

November 5, 2004

Calls and visits with wheat producers in the last couple of weeks led to more investigation. Producers are concerned; as well they should be, about what is happening to their wheat fields. The moisture this year prompted many to plant winter wheat a bit earlier than "normal". Moisture along with relatively warm temperatures also enabled the wheat to attain more growth than we have seen for some time.

The blessings of moisture and nice fall weather have led to another problem. Some fields are starting to have a yellow appearance and in some cases leaf die-back. There may be several causes for this event. Initial response is that an infestation of brown wheat mite has led to the wheat being infected with Barley Yellow Dwarf virus or wheat curl mites carried in some Wheat Streak Mosaic. Samples sent in to the Plant Diagnostic Lab in Fort Collins and contacts made with the Kansas State Extension have indicated another problem that was more or less unsuspected and that is leaf rust.

K-State Research and Extension crop specialist Jim Shroyer says they usually do not see the problem this far west because of the more arid climate. Infestations usually do not harm the wheat unless infestation occurs early in plant growth. Negative impact on winter survival and final yield are usually negligible if any. The sooner wheat goes dormant due to cold temperatures the better.

We now have to hope for a cold winter as the leaf rust will probably not survive. If the winter is warm however, some rust spore may survive, getting an early start next spring. Bob Hunger, a long-time wheat researcher from Oklahoma State University, indicates he has never seen a fall leaf rust infestation affect the final yield and that fall fungicide applications are economically unwarranted.

If you have further questions, please contact your local CSU Extension Office for information or to get plant samples tested.