AgriLife Research, Extension Entomologists Respond to Invasive Sugarcane Aphids in South Texas

A colony of sugarcane aphids on a sorghum leaf. Submitted photo.

A colony of sugarcane aphids on a sorghum leaf. Submitted photo.

CORPUS CHRISTI – Entomologists and plant breeders with Texas A&M AgriLife Research and Extension within the Departments of Entomology and Soil and Crop Sciences partnered to take care of a large outbreak of a very invasive pest: the sugarcane aphid attacking sorghum.

The team included Michael Brewer, Robert Bowling, Mo Way, James Woolley, Gary Peterson, Bill Rooney, Stephen Biles, and David Kerns of LSU. Graduate students also worked on this project, including John Gordy and Erin Maxson of the Department of Entomology, and Lloyd Mbulwe of Soil and Crop Sciences.

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A close-up of two winged sugarcane aphids and many unwinged aphids on a sorghum leaf. Submitted Photo.

First reported in the summer of 2013 on grain sorghum by Way, the aphid decreased yield up to 50% and produced a sticky residue called honeydew that caused grains to stick to plants, causing additional harvest problems. Brewer said the aphids have infested between 25 and 50 percent of the fields in the South Texas region in 2014.

The aphids overwinter in remnant sorghum plants after harvest and Johnsongrass. He said that with no threshold or monitoring protocols, the growers have been forced to use insecticides before knowing whether aphid populations reach problematic levels.

A close-up of two winged sugarcane aphids and many unwinged aphids on a sorghum leaf.

A close-up of two winged sugarcane aphids and many unwinged aphids on a sorghum leaf.

The team conducted sampling, insecticide, threshold, cultivar screening, and natural enemy studies in several areas of south Texas and Louisiana. They were able to establish monitoring recommendations and economic thresholds that allow growers to manage the aphid while maintaining natural enemies in the field. According to Brewer, when the growers sprayed when aphids were at threshold, they were able to reduce populations to manageable levels with little to no damage to predator populations, and often needed only one insecticide application to control the pest.

Sugarcane Aphid Occurrence in Sorghum map in 2013. Photo by Robert Bowling.

Sugarcane Aphid Occurrence in Sorghum map in 2013. Photo by Robert Bowling.

Maxson, Woolley, and Brewer have found several natural enemies of these aphids, including syrphid flies, lady beetles, and green lacewings, as well as several parasitoids, such as aphelinid wasps, a minute stingless wasp that only attacks aphids.

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Sugarcane Aphid Occurrence map in Sorghum and Johnsongrass in September 30, 2015. Photo by Robert Bowling.

The end result of this project included better detection of aphids, which now have spread farther north into the High Plains and up to northern Kansas, and all the way to the eastern seaboard. This is a tremendous range expansion from the areas where Way and others first detected it in 2013.

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Sugarcane Aphid Occurrence map in Sorghum in September 30, 2015. Photo by Robert Bowling.

The outreach and research activities from this project has helped growers in the near term to effectively control the aphids with insecticides over about 400,000 acres of South Texas sorghum at a benefit of $25-$50 million for 2014. These savings are at least doubled, adding in prevented losses, Brewer said.

“We (entomologists and plant breeders, researchers and Extension specialists) are able to work together to address sugarcane aphid on sorghum as a team,” Brewer said. “We continue to work together to find the best insecticide use, biological control, and sorghum resistance to limit damage from this aphid.” Outreach publications and student and staff presentations can be found at http://ccag.tamu.edu/sugarcane-aphid/

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