WOOSTER, Ohio — While most wheat in Ohio is at the early grain fill stage of development, growers should still scout for stripe rust, because some farmers have reported finding the disease in their fields.
For those who do find the disease, there still may be time to apply a fungicide to fields planted with susceptible varieties, said Ohio State University Extension wheat researcher Pierce Paul, who is also a plant pathologist with the Ohio Agricultural Research and Development Center.
Wheat crops can be affected by three types of rust: stem, stripe and leaf rust, with leaf rust being the most commonly found in Ohio. While levels of leaf rust and other diseases have been low thus far this season, some farmers have reported that stripe rust is developing in their fields, Paul said.
Symptoms of stripe rust include pustules that are small and round and usually occur in groups, forming yellowish-orange stripes on the leaf surface, hence the name.
“Only fields planted with highly susceptible varieties are being affected,” Paul said.
“Unlike leaf rust, which prefers warmer conditions, optimum of 68 to 77 degrees, stripe rust develops best under cool conditions similar to those we have experienced over the last few weeks.”
The issue is significant, considering stripe rust is a disease that attacks the leaves of the wheat plant. The disease reduces a plant’s ability to absorb sunlight and reduces grain fill.
Paul said farmers need to read fungicide labels and pay attention to pre-harvest intervals before making a decision to apply a fungicide.
“Fungicides with full head emergence (Feekes 10.5) as the harvest restriction should not be applied, whereas other products cannot be applied later than 30 to 40 days before harvest.
“With harvest likely to begin somewhere between mid- and late June, most available fungicides are either already off-label or will soon be off-label.”
This latest bump comes as the U.S. Department of Agriculture forecasts a yield of 47.6 bushels per acre nationwide, as of May 1, an increase of 40 percent from last year’s drought-ravaged harvest and the best since 2003.
In Ohio, the forecast is for a yield of 63 bushels per acre, an increase from last year’s 58 bushels per acre, said Charlie Russell of USDA’s National Agricultural Statistics Service Ohio field office.
The agency estimates the Ohio wheat crop will total 33.3 million bushels this year.
“Occurring this early during grain fill, stripe rust may still affect yield if high levels develop on the flag leaf,” Paul said.
“However, the warm, dry weather forecasted for the next few weeks will likely slow this disease down considerably.”