Wheat disease update – 11 February 2015

Wheat disease updates are written by Dr. Bob Hunger, OSU Extension Plant Pathologist

Oklahoma: Reports of diseases in Oklahoma have been sparse (as expected for this time of year) but certainly more numerous than last year when drought curtailed foliar diseases.  Yesterday (10-Feb) I found wheat leaf rust at a low, but consistent level in guard strips of Jagalene planted around a large wheat breeder nursery here in Stillwater.  Susceptible-type pustules were on lower leaves at 15-25%.  As temperature increases and with moisture this rust will increase and spread.

Gary Strickland (Extension Educator – southwest Oklahoma) indicated to me that he had heard reports of some leaf rust in Tillman County and also has seen a few pustules here and there on wheat in Jackson County, but nothing severe.  He has seen no powdery mildew and no root rots to speak of.  He also indicated there were a lot of acres of “little wheat” with some looking good if moisture had been received but that the southwest OK was quickly drying out.

Symptoms of wheat soilborne mosaic/wheat spindle streak mosaic (SB/SS) have shown up in Dr. Edward’s variety demonstration as well as in my SB/SS evaluation nursery, but symptoms are not yet striking as the flush of spring growth has not yet started.

Wheat soilborne mosaic virus can cause yellowing in the spring in susceptible varieties such as the one on the left.

Wheat soilborne mosaic virus can cause yellowing in the spring in susceptible varieties such as the one on the left.


Reports/excerpts of reports from other states:

Louisiana; Dr. Stephen Harrison (Professor; Wheat & Oat Breeder, LSU AGCenter) 3-Feb-2015:  “Stripe rust has been reported in several commercial fields and nurseries around central and northeast Louisiana.”


Texas Dr. Amir Ibrahim (Prof, Small Grains Breeding and Genetics, Texas A&M AgriLife Research) 3-Feb-2015:  “Wheat stripe rust found in Texas Blacklands area:  On January 29th, Russell Sutton, Assistant Research Scientist with the Small Grains program at Texas A&M University and our anchor in the northern Blacklands area and northeast Texas, visited our research plots near Ennis Texas. Russell found a small hot spot of stripe rust on the susceptible variety ‘Patton’ that we use as a spreader. The spot was about three feet in diameter and the lower leaves where heavily infected. The wheat appears to have completed the tillering stage and ready to begin jointing.  Russell will return in two weeks and collect some spores and look for more infection sites.

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