2013 Wheat Disease Updates
Stripe Rust Update (5/11/13)
The wheat is heading and flowering in southeastern and south central Kansas this week. Wheat in central Kansas is mostly in the boot stages of development with the most advanced fields beginning to head this weekend. The wheat in southwestern KS continues to struggle with drought and freeze damage and growth stage varies widely among fields.
Disease scouting this week suggests the risk of severe rust epidemics remains low in Kansas this year. I had a few more reports of trace levels of stripe rust in southeastern KS where the wheat is flowering. The levels of stripe rust are very low at this time. Temperatures are forecast to reach the upper 80's early next week with low temps at or above 60 F. Temperatures in this range often slow the development of stripe rust but farmers in these areas should monitor the disease carefully.
I was able to find a single pustule of leaf rust in Stafford county Kansas this week, but the wheat at this location was thin from recent dry conditions. I suspect the leaf rust will not increase rapidly at this location. Other fields that I checked in southwest KS (Finney and Kiowa counties) show significant drought stress and no sign of rust. In south central and central Kansas (Pratt, Reno, and McPherson counties), the wheat is in better condition with thick canopies and good moisture recently. I found no leaf rust, stripe rust or stem rust in these areas; however, several fields had moderate levels of powdery mildew. Symptoms of barley yellow dwarf remain low or absent in all fields I have checked to date.
-Erick De Wolf, Kansas State University Extension Plant Pathologist
2013 Wheat Disease Update
Early Season Wheat Disease Update for Kansas (3/22/13):
March is an important month for wheat disease development in Kansas. This statement may surprise some of you, because the wheat is only just greening up in some areas of the state.
As it turns out, February and March are important because we often receive our first reports of disease activity from states to our south. This is particularly relevant for the rust diseases, which often survive the winter in these southern climates.
So far this year there are several reports of rust developing in Texas, Arkansas, Louisiana, and Mississippi. Stripe rust has been observed in all four states and appears to be spreading beyond the initial foci of infection. Leaf rust has been reported in Texas but not the other states.
The reports of stripe rust and leaf rust from Texas are the most important for us, because weather systems often transport the rust spores from these regions into Oklahoma and Kansas. Varieties such as Everest, Armour, and TAM 111 are being affected in Texas this year. This is similar to what was observed in 2012 and there are no reports of new races of stripe rust to date.
Bob Hunger, wheat disease specialist for Oklahoma State University, is reporting no finds of rust in Oklahoma as of March 21. Growers in Kansas should be monitoring the situation in Texas and Oklahoma. If the disease continues to develop in Texas or is reported in Oklahoma, we will need to evaluate the need for fungicides to suppress rust development in fields planted to susceptible varieties.
-Erick DeWolf, K-State Wheat Pathologist
Texas (12 mi west of San Antonio) (3/7/13): I toured our rust evaluation nursery located 12 miles west of San Antonio, TX on March 07, 2013. The crop stage varies from Feekes 4 to 10.5 depending on growth habit and source. The wheat crop is early by at least two weeks compared to long term average (spring and winter wheat).
Leaf Rust is also developing uniformly in the lower to mid canopy of 'TAM 110'. Consistent with previous years, there is more leaf rust in the observation head-rows as compared to the yield trials.
Stripe/yellow rust (Yr) is still developing in the lower to mid canopy of the spreaders, including 'Patton'. Both Lr and Yr (30S) are present on the same leaves of 'TAM 112'.
No indication of a leaf or yellow rust race change but it is early to tell at this point.
-Amir Ibrahim (Texas A&M small grains breeder)
Oklahoma (2/26/2013): Although still no confirmed reports of foliar disease in Oklahoma wheat, the recent moisture will facilitate foliar disease development as temperatures raise as we enter March. Symptoms of wheat soilborne mosaic/wheat spindle streak mosaic are evident in that disease nursery here at Stillwater and with the wet/cold weather of this and last week should become more prominent as we get into March.
Bob Hunger (OSU Extension Plant Pathologist)
Texas: Uvalde (West of San Antonio) (2/23/2013): The wheat crop is at Feekes 4-5. Leaf rust continues to develop uniformly at this location and is severe on susceptible cultivars such as "TAM 110". Stripe rust continues to develop but might be slowed by increasing temperatures at this location. It seems we have the same race that was virulent on "Everest" and "TAM 111" last year.
-Amir M.H. Ibrahim (Texas A&M Small Grains Breeder)