The pest has developed an appetite for sorghum.
Sugarcane aphids moved into Kansas last year and despite their name, appear to have developed an appetite for the sorghum crop.
“The sorghum-loving sugarcane aphid populations now overwinter in Texas and are passively swept northward when the weather warms,” said Kansas State University entomologist Sarah Zukoff.
The pests can reduce crop yields and excrete a sticky substance called honeydew, which is left on the plant’s leaves, stems and heads and can interfere with grain harvest.
There’s a lot at stake for Kansas, which leads other states in sorghum production, often by a wide margin. Last year, Kansas produced nearly 200 million bushels of the total U.S. production of 433 million bushels. Texas was No. 2 at just more than 137 million bushels.
Sugarcane aphids have been a problem for sugarcane producers in southeastern states for years but were detected in sorghum in Texas in 2013. Since then, they’ve been found in states all the way to the Atlantic coast and as far north as Kansas. This year, they’ve been found in 36 Kansas counties, as far north as Cloud County and as far west as Haskell County, said Zukoff, who is based at K-State’s Southwest Research-Extension Center in Garden City.
The number of sugarcane aphids found in most counties this year has been large enough that sorghum growers in many cases have treated their fields at least once with insecticides labeled for use on the pests.
The aphid has a smooth body with a light-yellow colored head and light-colored legs with dark feet. They have dark-colored, short cornicles that look like tailpipes. They are sometimes called white sugarcane aphids, and they can be confused with yellow sugarcane aphids, corn leaf aphids or greenbugs, as they superficially resemble these other sorghum aphids.
The insects are found on the underneath side of sorghum leaves. Leaves below infested ones will be covered with honeydew and will appear shiny. These leaves become colonized with sooty mold after a short time in humid conditions.
Zukoff is encouraging growers to scout their fields once a week by walking 25 feet into the field and examining plants along 50 feet of row.
- If honeydew is present, look for sugarcane aphids on the underside of a leaf above the honeydew.
- Inspect the underside of leaves from the upper and lower canopy from 15 to 20 plants per location.
- Sample each side of the field, as well as sites near Johnsongrass and tall mutant plants.
- Check at least four locations per field for a total of 60 to 80 plants.
K-State entomologists have developed a guide for scouting for sugarcane aphids at http://myfields.info/sites/default/files/page/ScoutCard%20KSU%20reduced%20v3.pdf.
More information, including photos, is available at local K-State Research and Extension offices and online at http://blogs.k-state.edu/kansasbugs/.
