Growers throughout the southern U.S. are trying to ward off a new crop pest as sugarcane aphids make their way to fields of grain sorghum in Alabama for the second year in a row.
The pests were first found in the U.S. in 1977 in Florida and appeared in Louisiana in 1999. New research indicates that the aphids in Florida and Louisiana came from Hawaii. Sugarcane aphids can be found anywhere sugarcane and sorghum is grown, but are known to feed on a variety of grassy hosts.
With approximately 60,000 acres of grain sorghum planted in Alabama this year — three times the planted acres in past years — knowledge of these pests is imperative for farmers looking to maintain high crop yields.
Alabama Extension entomologist Dr. Kathy Flanders said these aphids were only found on sugarcane in the U.S. before 2013.
“Something happened in 2013 such that there were sugarcane aphids that could feed on grain sorghum in Louisiana and Texas,” Flanders said. “Researchers are still testing to determine what caused the host switch.”
Sugarcane aphids were first found in Alabama in July 2014. Christy Hicks, Alabama Extension’s regional crops agent serving east Alabama said although there was damage last year, producers in the 12 counties she serves have planted more than 1,500 acres in grain sorghum this year.
Kimberly Wilkins, a regional crops agents based in southwest Alabama said lots of aphids have been found in Baldwin County. In spite of the potential pest problems, farmers in her area have nearly tripled the acres planted in grain sorghum since last year.
“Farmers are working to find the best chemicals to get control of sugarcane aphids,” Wilkins said. “They are also trying to protect beneficial insects since we believe the beneficials could help with the aphid problem. The aphids come on so fast. It is a battle to find and treat them fast enough.”
Flanders said routine scouting is the best way to stay ahead of pest problems in the field. She recommends checking weekly from emergence until aphids are found and twice a week after finding aphids. Aphids feed on the underside of lower leaves on sorghum plants, so thorough checks of plants are essential. If populations are too high, pesticide applications will be a necessity.
Flanders also said it is important to ensure the spray reaches lower leaf layers, since the aphids feed on the undersides of leaves — especially the lower leaves.
“The more water used, the better the penetration down into the canopy,” Flanders said. “It is also important to use a high sprayer pressure and nozzles that deliver small sized spray droplets.”
Flanders said the best way to stay abreast of the problem is to be proactive. Log on to www.aces.edu for more information, timely information sheets, and recommended practices, or contact your local Extension agent.