For 2017, growers and agronomists are being urged to monitor and report the aphids’ progression throughout the season using pest scouting apps like MyField.info, a tool developed by Kansas State University in cooperation with the U.S. Department of Agriculture, which collects scouting reports and generates real-time maps of where infestations are occurring.

Sorghum growers across the Southern Plains this spring were urged to plant sugarcane aphid tolerant hybrids to stem the migration and quick proliferation of the sticky pest, which tends to follow a northward seasonal path similar to rust infestations in wheat.

The National Sorghum Producers compiled a list of more than 30 sorghum hybrids from more than a dozen different seed companies that are independently verified to be aphid tolerant. The list includes white food-grade sorghum as well as conventional grain.

Industry leaders emphasized that growers who plant these hybrids aren’t just improving yield prospects and potentially minimizing spray applications in their own fields, they are also helping the industry collectively combat the problem.

“If we can plant resistant varieties over a wide area, we are hoping we can slow the aphids’ growth rate and then the natural predators can come in and help us,” summarized Norm Elliott, a research biologist with the Ag Research Service based at Stillwater, Oklahoma.

One of the things that make the aphids so damaging is their explosive reproductive capability.

“Their natural enemies can’t keep up with the aphids because they reproduce at such a fast rate,” he explained. “Their reproductive rate is twice the rate of greenbugs.”

Elliott and his team won a grant to study an area-wide management approach. Sugarcane aphids are migratory; they overwinter in South Texas before working their way northward and fanning out across Oklahoma and Kansas.

They’ve made it as far northwest as Baca County in southeastern Colorado, where they arrived late in the season last year but still prompted the need for pesticide applications, according to Kevin Larson, superintendent at the Plainsman Research Station at Walsh, Colorado.

“These little bugs were tougher than I expected,” he said. “They caused a lot of harvest problems for us.”

They also emerged in troublesome numbers for the first time last year around Clovis, New Mexico, where most of that state’s sorghum is grown.

ARS research will examine when, where and how fast the aphids migrate so that better predictions can be made about where they are headed next.

Their migratory habits are still not well understood. One rain can fuel a population explosion overnight. They also appear to favor lush fields. Larson said at the Walsh station hail-damaged sorghum outperformed the undamaged sorghum because the aphids were so thick on the healthy plants.

Because infestation levels can vary so much even between neighboring fields, growers are urged to always scout thoroughly across multiple locations.

It’s also not entirely clear why the aphids prefer some hybrids to others, but the differences are enough to slow their growth and stem yield losses. Tolerance should not be mistaken for immunity, however. Agronomists say tolerant varieties might still need to be sprayed, just fewer times.

Currently there aren’t many short-season hybrids on the tolerant list, so Larson is looking for more options that will work for growers in southeast Colorado, he said.

Most of the tolerance is coming from a single genetic line, but new strains of resistance are in the breeding pipeline, according to Tim Lust, NSP executive director.

“With the new gene-mapping technology we have now, when desired traits are found in the lab, as soon as they find it they can go straight into elite germplasm with it very quickly and easily,” he said. “By 2018 or 2019, we’ll have some stuff coming out that is the first wave of that, and then we can start stacking these genes, and get a better resistance level.”

For 2017, growers and agronomists are being urged to monitor and report the aphids’ progression throughout the season using pest scouting apps like MyField.info, a tool developed by Kansas State University in cooperation with the U.S. Department of Agriculture, which collects scouting reports and generates real-time maps of where infestations are occurring.

So far, the sorghum check-off has invested around $1 million in researching remedies and providing producer education.

“I heard from some of my colleagues down at Corpus Christi that some of their fields last year didn’t need to be sprayed, and that’s where it showed up first,” noted Tom Royer, an Oklahoma State University entomologist. “So there’s light at the end of the tunnel in managing this pest.”

“We may learn some really interesting things down the line. We may see some changes and some shifting due to plantings of tolerant hybrids over a large area,” he continued. “In the meantime we have two pesticide options that are effective (Transform and Sivanto) and there are some other products that would work if the companies sought registration for that.”

Brent Bean, NSP’s on-staff agronomist, urged growers to rotate their pesticides to prevent resistance from building and to make careful, thorough application of the chemical to insure maximum effectiveness.

“We’ve faced the onslaught of the aphid, and we’re at the point now it is manageable,” Royer said. “But it’s going to take some serious oversight. We can’t just put the crop out there and ignore it like we used to.”