Stripe Rust update in the Panhandle
Robert M. Harveson, Extension Plant Pathologist, Panhandle R&E Center, Scottsbluff
Reports of stripe rust in wheat, caused by Puccinia striiformis f. sp. tritici, were noted this fall throughout Panhandle wheat fields, particularly in Kimball and Banner counties.
Now, reports of additional epidemics ranging from Garden County in the east to the Wyoming border in the west and to northern Box Butte County near Hemingford have come in, since we requested local reports via the news media.
This is the third successive year that stripe rust has been found on fall-planted wheat in the Panhandle (2014-16). These findings have also coincided with disease outbreaks resulting in serious damage in 2015 and 2016 from numerous locations. The findings from October-November of 2016 suggest that we need to be attentive to the possibility of disease outbreaks again in 2017.
Because of the uncertainty of recommending fungicide applications on fall-planted crops, we implemented several very simple field experiments in mid-November with the assistance of crop consultants and wheat producers, in an attempt to gather preliminary data for evaluating the efficiency and importance for fall fungicide applications for future reference. These trials were begun at numerous sites throughout the Panhandle, in both commercial wheat fields and University of Nebraska-Lincoln research plots.
I also want to thank readers for their responses to requests for reports of rust occurring in home lawns. This concept has expanded beyond the North Platte Valley, and I have received phone calls and emails informing me of rust appearing in locations ranging from Chadron in the north, to Oshkosh and Lisco in the east, to Kimball in the south, and Scottsbluff-Gering in the west. This indicates that rust has been identified throughout the entire panhandle before winter really set in.
At this point we are unsure of how this may affect wheat crops in 2017, but these widespread findings are very unusual. These infections in lawn grasses could serve as a reservoir for pathogen survival over the winter, potentially resulting in early infections of wheat crops next spring.
It also suggests that the same phenomenon could also potentially occur in some perennial grass weed if insulated with a layer of snow. Stripe rust was identified from jointed goat grass earlier this summer. It is something to keep an eye on this spring when lawns and wheat crops emerge from dormancy.