The wheat crop in Kansas is now at the flag leaf emergence stage of growth in much of southern and central Kansas. The crop is at mid- to late-joining in the west central and northwest regions of the state. Stripe rust continues to be our primary focus this week with new reports from additional counties and further disease development in central Kansas. The disease is still limited to the lower leaves for the most part with occasional mid canopy leaves with trace levels. The incidence of stripe rust on the lower leaves of susceptible varieties ranges from 1-30%.
Leaf rust was observed at multiple locations in central Kansas this week also. As with stripe rust, leaf rust is also on the lower leaves. Only trace levels have been found so far in most plots. We did observe a few fields and plots in Reno and McPherson counties with incidence of leaf rust approaching 90% on the lower leaves. The severity of the infection was still low (<10%) in most cases. The dry conditions may be slowing the spread of leaf diseases temporarily, but growers should be watching this situation carefully. Be prepared to apply a fungicide if disease continues to progress.
By Ryan Flaming, KSU County Extension Agent, Agriculture & Natural Resources