Farmers prep for summertime sugarcane aphid threat in Kansas

They’re tiny. They’re destructive. And they could be on the way to the Sunflower State again.

Farmers are trying to get ready for the sugarcane aphid and the damage it can cause.

It’s a pest that, as you’d expect from the name, plagued sugarcane farmers for years, mainly in the South. Recently, the aphids have developed a liking for grain sorghum. Kansas is the nation’s biggest grain sorghum producer.

They’ve swept from south Texas into Oklahoma and Kansas each of the past two years. And, after a mild winter, they could make an encore in 2016.

But it’s too early to tell how hard Kansas will be hit, Kansas State University professor Brian McCornack says.

“The eight-ball gets a little bit more murky,” McCornack told farmers at the Sedgwick County Extension Office recently.

It depends, he said, on when they come from the south.

Emerging pest

Sugarcane aphids are small, a little more than a millimeter long. They have:

▪ A smooth body with a light-yellow head

▪ Light-colored legs with dark feet

▪ Dark-colored, backward-pointing tubes called cornicles that resemble tailpipes

Farmers in southern states like Florida have long dealt with the pest in their sugarcane fields.

But a few years ago, sugarcane aphids decided they liked the taste of grain sorghum, also known as milo, a major feed grain for cattle. It also can serve as a substitute for wheat in gluten-free food products.

More than 3 million acres of grain sorghum were harvested last year statewide, according to federal data.

The crop made more than $755 million for Kansas farms in 2014, according to the Kansas Department of Agriculture.

Researchers in Kansas knew little about this type of aphid because of its southern origins and its traditional focus on sugarcane.

“I’ve worked with aphids for about 10 to 15 years, and sugarcane aphids scare me, mainly because of how fast it can reproduce,” McCornack said. “The kicker is it won’t even go back to sugarcane.”

‘Spread like wildfire’

In 2014, the bugs were spotted very late in the growing season in Sedgwick and Sumner counties. Farmers typically harvest in September, October or November. Last year, the bugs appeared in late July, much earlier than expected.

“To find them this early was kind of nerve-wracking for us,” said extension agent Zach Simon.

Sedgwick County was one of the first places in Kansas to see the aphids. They moved west and north, nearly reaching the Nebraska state line. A total of 36 counties in Kansas saw sugarcane aphids last year, according to Kansas State University.

“They spread like wildfire, but kind of the epicenter was here,” Simon said.

Neighboring counties also struggled with the pest.

“We got hammered pretty hard last year by them,” said Sumner County extension agent Randy Hein. “We had some the year before, but last year was the worst year.”

One obstacle to stopping their spread was the lack of knowledge in Kansas about them. Another challenge was how quickly they spread.

“They multiply so quickly that, you know, if you sprayed your field and the neighbor didn’t spray his at the same time, they’d jump across the road onto yours,” Hein said. “It was a mess.”

While some producers did suffer yield losses, it could have been worse. Sedgwick County extension agents ran tests to see what concentrations of insecticide would stop the advance and gave that information to farmers.

“I had my best harvest on record as a producer, and I give a lot of the credit to that to K-State Extension,” said Kenneth Winter, a farmer in the northwest part of the county.

The office is funded by Sedgwick County and grants from the federal government and K-State.

What’s next

Farmers now are watching to see when the aphids are going to get here.

“It really depends on … how much those fields down south of us are building,” McCornack said. “Those aphids get in the jet stream and literally rain out of the sky.”

Even though the official start of summer is almost two months away, the aphids are already busy in some parts of the South.

The Rio Grande Valley in south Texas is seeing its first spike in the sugarcane aphid population, said Danielle Sekula-Ortiz, an integrated pest management agent with Texas A&M AgriLife Extension.

“Sugarcane aphids are making flight and starting to move into commercial sorghum fields and start to reproduce. Currently, we’re seeing populations anywhere from 50 and 150 per leaf throughout the valley,” she said. “I have some growers that are starting to see a thousand sugarcane aphids per leaf.”

McCornack said the pest spent the winter as far north as the Dallas area, which was about the same area as last winter.

“We have some things that are pointing to a season similar to last year,” McCornack said. “(But) a lot can happen between now and the time they actually arrive.”

Some farmers in Kansas are moving away from growing grain sorghum because of the pest.

“I’ve talked to a few people that said they’re going to plant more corn and not as much sorghum, or they may not plant any sorghum at all because of the aphid problem,” Hein said.

‘We are down to one’

Predators like lady beetles can make a dent in a new invasive species like the sugarcane aphid. But Simon said that doesn’t happen overnight.

“It usually takes these predators several years to kind of come up to speed with this new pest,” Simon said.

Sedgwick County farmers used two insecticides last year to fight off the aphids. But a federal ruling put limits on one of the products, Transform. Some environmentalists cited the harm the product does to bee populations.

“We are down to one,” Simon says. “That will be a challenge for producers this year.”

The state applied for an exemption to use the insecticide to combat sugarcane aphids. Oklahoma and Louisiana have also applied.

They’re hoping the feds say yes, as they did for Texas by approving emergency use of the chemical.

“It’s always nice to have options,” said Robert Bowling, the Corpus Christi-based head of Texas A&M AgriLife Extension’s sugarcane aphid task force. “It was huge for Texas.”

Otherwise, they’ll have to use just the insecticide Sivanto. That could allow the aphids to develop a resistance to it, said David Kerns, a Louisiana State University professor doing research in northeastern Louisiana.

“We’d like to be able to rotate the products to be able to prevent resistance from developing as quickly,” Kerns said.

Three steps

McCornack told farmers to scout early and scout often for the sugarcane aphids in their fields.

He also said grain producers need to carefully consider when to spray insecticide. They need to make sure it doesn’t kill off too many “beneficials,” or insects that help producers by preying on the sugarcane aphid and other pests.

Farmer Nathan Kohls dealt with the aphids last summer. He said he’d come in from working in fields near Clearwater covered in the sticky honey dew that the aphids leave behind.

“We didn’t know how fast they were going to populate,” Kohls said. “I think we can control the aphids. It’s just expensive.”

That’s why producers will need to choose the right time to “pull the trigger” and spray their fields, McCornack said.

“It’s not cost-effective to do this multiple times,” he said. “But losing 70 percent of your field is not cost-effective either.”

This story was originally published April 27, 2016 at 8:40 PM with the headline "Farmers prep for summertime sugarcane aphid threat in Kansas."