Big Yields, Tiny Aphids in Crosshairs

April 23, 2016 02:42 AM
Big Yields, Tiny Aphids in Crosshairs

Kansas sorghum grower strokes benchmark bests in 2015

Ear to the ground, Kent Winter knew an army of millions was set to roll across his Kansas farm.

In late July 2015, the invasion began. Waves of white sugarcane aphids settled across his grain sorghum, threatening to destroy yield and turn the fields into a sticky honeydew mess capable of clogging combines. He steadied his nerve, placed chemical crosshairs on the aphids and waited for a clear shot. When Winter squeezed the trigger, he didn’t know he was protecting the best sorghum crop of his life.

Similar to many areas in the Midwest during the 2015 planting season, Winter’s Sedgwick County fields were pounded by extreme rains at the end of May and into early June. Typically, he begins planting grain sorghum 
June 10, but the heavy moisture pushed planting to June 20. With plenty of Kansas heat units bearing down in midsummer, the late planting wasn’t a negative issue. Winter bumped his planting population to 45,000 seeds per acre on 30" rows, protected by a Concep III treatment.

Winter used a single sorghum variety, Pioneer 85G0, across full-season, dryland acreage in 2015. Limited double-crop acres were no-tilled with Pioneer 86G32 behind wheat stubble. 

Winter treats grain sorghum as a first-rate provider, no different from any other crop. “We try to manage sorghum just as aggressively and effectively as other crops,” he says. On fertility, Winter adheres to 1.2 lb.of nitrogen per bushel of expected yield and adjusts the application rate according to carryover nitrogen found in soil tests. Usually, he puts on anhydrous ammonia with a chisel in mid-spring, but the rains forced a change and he chose to spread urea the week before planting.

   The white sugarcane aphid can destroy   yields and clog combines.

Timing of nitrogen is a huge key to grain sorghum success, says agronomist Michael Speer, Farmers Co-op Elevator Co., Mt. Hope, Kan. “Two weeks before Kent’s grain sorghum headed out, we hit it with another 35 lb. to 40 lb. of nitrogen. When he plants, he’ll put down 6 gal. or 7 gal. of 28% liquid UAN,” Speer describes. “On double-crop grain sorghum, he’ll also come back later and top-dress with urea.”

As the growing season headed into July, Winter kept seeing favorable skies carrying buckets of rain. Most years, Sedgwick County is battered by a hot and dry punch combo, but timely moisture was available much of the summer. Winter knew the rain could translate to substantial yield gains. “I looked out my window at the surrounding countryside several times and said to my wife, ‘I don’t think we’re in Kansas anymore.’”

Yet, there is no crop management without wrinkles. Sugarcane aphids jumped into Louisiana grain sorghum in 2013 and spread to surrounding states at a quick march. Winter had been given ample warning by Kansas State University (KSU) Extension personnel to be on the lookout for sugarcane aphids blowing in from the south. 

Zach Simon, KSU Extension, watched the map light up south of Sedgwick County as aphids advanced into Kansas. Simon hosted an early August meeting for growers. “We tried not to cause panic, but we still wanted to emphasize the severity of the situation,” he explains. “We told growers to scout, figure the percentage of a field’s infestation and then treat.”

When the aphids reached Winter’s farm, 100°F summer temperatures enhanced their rate of reproduction. Sticky shiny residue was beginning to form in fields as Winter held back until colonies were 20% infested. Then he unleashed a ground-rig sprayer at the beginning of August with 4 oz. of Sivanto and 20 gal. of water per acre to ensure adequate coverage. His timing was spot-on, and the single application carried the day. 

“Kent did well,” Simon recalls. “Other growers got smoked. Due to aphid damage, a few fields weren’t harvested, period.”

“We jumped on sugarcane aphids earlier than others and it worked,” Speer says. “I don’t know about this year. Experts tell us we needed a hard winter to keep them south, but we had mild weather. We’re a little nervous the infestation might be worse in 2016.”

   Kansas producer Kent Winter never     dreamed he’d grow the best grain    sorghum of his career and battle a    brand new pest all in the same year. 

When the smoke cleared after the aphid battle, Winter’s November fields were waiting with the best sorghum yields of his career. Even after moisture shrink, he hit dryland milo yields of 150 bu. per acre, compared with his typical yields in the 90-bu. to 105-bu.-per-acre range. His double-crop sorghum was also outstanding, tallying 127 bu. per acre. “I attribute the big yields to God’s blessing with timely, beneficial rains during the growing season,” Winter explains.

Based on a lifetime of experience with grain sorghum, he stresses fertility as the premier agronomic factor for strong yields. “Never cheat on fertility,” Winter says. “You’ve got to have adequate nitrogen to get strong bushels. It doesn’t matter which form, but it must be timely.”

On the heels of fertility, he emphasizes weed control. A clean first month of growth is vital, until the canopy closes. Anything less and weeds will dog sorghum until harvest. 

Resistant pigweed troubles began on some of Winter’s fields in 2013, and the problem has exploded. “With milo, get the pigweeds early or you’re in trouble, as there are very limited options to come back over the top of milo to control weeds,” Speer warns. “Resistance to Roundup has gone crazy. In 2015, we got barely any management out of Roundup at all.”  

Back to news


Spell Check

No comments have been posted to this News Article

Corn College TV Education Series


Get nearly 8 hours of educational video with Farm Journal's top agronomists. Produced in the field and neatly organized by topic, from spring prep to post-harvest. Order now!


Market Data provided by
Brought to you by Beyer