I have been getting some calls from farmers asking if their grain sorghum has sugarcane aphids in it? After going and looking I am glad to report that they are not sugarcane aphids. It is an aphid.
The corn leaf aphid, frequently infests sorghum at the whorl stage. This aphid ranges in color primarily from dark-green or bluish. Key identifying features are the dark legs and cornicles, relatively short antennae, and feeding on the upper leaf surfaces exclusively, preferring the upper parts of the plant.
Sugarcane aphids (SCA) on the other hand feed on the underside of leaves. They can be confused with other aphids especially when the aphids are young. They are pale yellow and have light colored legs with dark feet. They have dark colored, short cornicles (tail pipes) with no shading at the base of them as on the corn leaf aphid.
Both aphids do produce a sticky honeydew substance, for that matter any aphid or greenbug does, because they all have piercing-sucking mouth parts and are sucking the plant juices for nourishment. Corn leaf aphids do not have such a high reproductive rate as sugarcane aphids and therefore are not considered an economic treat to sorghum. Any aphid will attract beneficial species that will feed on them. The corn leaf aphid is rarely a cause for concern on sorghum unless larger numbers persist into heading and migrate up into the heads to continue feeding.
Monitoring your grain sorghum fields for the corn leaf aphid is advised at this time since the sorghum is heading out to ensure they don’t migrate up into the heads in large numbers. If they do there is an increased chance that reductions in seed weight might occur, but also keep in mind that corn leaf aphids do attract and even help to multiply populations of aphid natural enemies that contribute to their control.
A good resource to have or refer to is the “Sorghum Insect Management Guide” by K-State Research & Extension, it can be found on our web site at www.cottonwood.ksu.edu or simply type into your internet browser - sorghum insect management guide, ksu.
If you have any questions, please give me a call or email me.
Stacy Campbell is an Agriculture and Natural Resources agent for Cottonwood Extension District. Email him at firstname.lastname@example.org or call the Hays office, 785-628-9430.