Wheat on the Cooksey farm south of Roggen had taken on a coppery sheen but owner Jerry Cooksey wasn’t happy to see it.

Wheat on the Cooksey farm south of Roggen had taken on a coppery sheen but owner Jerry Cooksey wasn’t happy to see it.

“I don’t like that color,” he said.

The reddish gold hue wasn’t due to ripening but rather to a severe infestation of stripe rust, an unusual problem in Colorado but one that is widespread this year due to wet, cool conditions the past two months.

Diseases and late freezes are casting a shadow of uncertainty over the crop’s yield potential.

When harvest arrives in about three weeks, Cooksey guessed yields would range anywhere from 20 to 70 bushels per acre. He said his best looking varieties are Antero, a white wheat, and Byrd, both developed by Colorado State University. Along with K-State’s Denali, those varieties have been top performers in CSU’s recent yield tests.

Rain has continued to hamper the harvest as it moves from Oklahoma into Kansas. While head scab and low protein have been less of an issue than expected so far, rain on ripened wheat combined with high rust levels have lowered test weights in many fields, according to harvest reports from Oklahoma and Kansas.

In its most recent monthly estimate, the National Ag Statistics Service reduced yield expectations for Oklahoma and Texas, but raised them in Colorado and Kansas. With cool weather aiding the grain fill period, Colorado Wheat Executive Director Darrell Hanavan said he would not be surprised to see the state’s estimate of 85.5 million bushels go up even more.

“The estimators are being conservative because we’re dealing with conditions we’re not used to seeing,” he said.

Farmers say they have all the moisture they need to finish off the crop, so the arrival of hot, dry conditions should be advantageous. Hanavan said the crop was maturing about three weeks ahead of normal earlier this spring but has since slowed to fit a more normal time frame.

After wheat tour stops across the state, Hanavan said the best wheat appeared to be along the Front Range, which is a bit unusual. Beneficial snow cover during spring cold snaps probably helped, he said.

Meanwhile, the rains came too late to make up for winter drought stress in southeastern Colorado. Even so, prospects there are better than they have been in recent years, he said.

Rain fell heavily while the tour was visiting the Stulp Farm south of Lamar, and the plot at Walsh, which was scheduled for touring the following morning, was completely hailed out the night before. Overall, however, Hanavan didn’t think hail losses were out of the ordinary for this time of year.

According to CSU Director of Seed Programs Rick Novak, the healthiest wheat on the tour was at the Wickstrom farm, located north of Wiggins.

As Novak walked through the Cooksey plot, he noted that cool weather was masking tissue damage likely to intensify with hotter weather. Even so, plenty of injury from disease and freeze was already evident. He pointed to heads blackened by smut and others that were filling unevenly or only partially. He demonstrated how the stripe rust had migrated up into the wheat head and even onto the milk-stage kernels, something rarely seen.

“This is what happens when rust moves in early enough. With favorable temperatures, it continues to evolve,” he said.

CSU wheat breeder Scott Haley said he could remember fewer than a handful of times in the last 15 years that rust influenced variety trial outcomes. “Our number one breeding objective is drought,” he said. “This is really an outlier year.”

For that reason, he said farmers should base their variety selection on three-year averages rather than on data from this year’s test.

Novak has been fielding calls from growers concerned about the viability of next year’s seed in light of current conditions. In addition to controlling volunteer, he urged farmers to consider treating their seed.

Seed treatments are a given for many crops, such as a soybeans, but have never been a commonly accepted cultural practice among wheat farmers. This year could change that.

A variety of treatments, including insecticides, are available ranging in price from $2.50 to $10 an acre, Novak said. They protect against seedling stage diseases including viruses and head scabs, smuts and bunts. Foliar diseases like rust, on the other hand, strike plant tissue during the growing stage and are best controlled with field level or aerial application of fungicides. Such applications were common this spring, but timing was critical. Some infestations overwhelmed fields even after they’d been sprayed twice.

Rust doesn’t affect germination rate but it can impact the vigor of the seed, Novak said, another reason to consider seed treatments this fall.

The multi-generational Cooksey farm, which sells around 100,000 bushels of seed wheat annually, purchased seed treatment equipment last year.

“I think with this type of year and with the stinking smut problem we had last year in northeastern Colorado it will be an easier sell this season,” Jerry Cooksey said.

“The thing that’s working against us is the wheat price,” he added. Average cash price for wheat is currently in the $5 per bushel range after peaking at over $9 in late 2007.