Louisiana’s grain sorghum acreage has dwindled in the past few years to a tiny fraction of what was grown just a decade ago — a shift driven by a shrinking market and problems with an insect called the sugarcane aphid.
Still, LSU AgCenter experts said at a Nov. 7 meeting, grain sorghum, which also is known as milo, deserves a fresh look. It is an ideal crop to rotate with cotton and soybeans, they said, and good management practices can result in higher yields and less insect damage.
The meeting was at the AgCenter office in Avoyelles Parish, where more than half of Louisiana’s 5,000 acres of grain sorghum were grown in 2018. In the mid-2000s, acreage was about 250,000.
“The sugarcane aphid ran a lot of our farmers out of production, along with price,” said AgCenter entomologist Sebe Brown. “What this insect can do is shocking.”
Severe aphid damage essentially sterilizes sorghum grain heads, and the insects leave behind a sticky “honeydew” that can jam harvesting equipment. Left unchecked, the aphids can cause entire fields to fail, Brown said.
But, he added, “we can still grow grain sorghum economically in Louisiana.”
Farmers should select hybrids that are tolerant of aphid damage and use insecticide-treated seed, he said. Planting as early as possible, usually in the first part of April, lets plants begin developing while temperatures are still cool, and insects are less active.
During the growing season, it’s important to diligently monitor fields and spray them with insecticide if there are 50 or more aphids per leaf on 20 percent of a field. Spraying must be done in a timely manner, Brown said, before the aphids take the crop beyond the point of rescue.
“Treating at 50 aphids per leaf is a lot easier that treating at 10,000 aphids per leaf,” he said.
Farmers also need to give the same attention to sorghum as their other crops.
“A lot of times, we treat sorghum like a stepchild,” said AgCenter grain sorghum specialist Dan Fromme.
Manage the Crop
Sorghum is not a major crop in Louisiana, so it is sometimes relegated to lower-quality land, he said. Many farmers cut corners on inputs and don’t apply the appropriate amount of nitrogen, potassium and phosphorous to sorghum.
Those decisions lead to yields — and profits — much lower than the plant’s potential, despite Louisiana having far more abundant rainfall than the leading sorghum-producing states — Texas, Kansas and Oklahoma.
“You very much get a response from nitrogen,” said Brent Bean, director of agronomy for the United Sorghum Checkoff Program. “It’s a common mistake. People just don’t fertilize their sorghum. It needs about the same amount as corn.”
Bean also spoke at the meeting about the sorghum market. Between 75 and 80 percent of U.S. sorghum had gone to China in recent years, but that has changed since tariffs were imposed on American commodities amid trade tensions, he said.
Michael Deliberto, an AgCenter economist, said U.S. sorghum exports are down about 27 percent since last year. But the supply has increased due to greater productivity, and sorghum is being used more domestically for livestock feed and ethanol.
That means farmers could get slightly better prices — perhaps about $3.30 per bushel, a few cents higher than last year’s prices — in the coming year, he said.