In summer of 2014, this new invasive pest of grain sorghum appeared in Georgia. We knew it would be back this season, probably earlier, and it has. The first documented 2015 appearance on sorghum was identified this past week in Brooks County and now Thomas County. Yesterday I checked waist high sorghum and found aphids and cast skins on a few plants. You can see the white cast skins on the leaf. The aphids are black, which is likely from a parasitic wasp. UGA Extension Entomologist Dr. David Buntin says Aphelinus sp. wasp is reported in the Delta and Texas region but was not seen here last year. We mailed the leaves to him to observe for this wasp. Wasps have hatched from some aphids that appear more brown. You can also see an exit hole.
We need to begin scouting and actively managing sorghum fields for the sugarcane aphid. SCA is difficult to manage cost effectively but planning and scouting are our best hope in managing this pest successfully and preventing losses. The sugarcane aphid can be identified by the pale cream to yellow color with no bumps or tubercles on the body, but with black feet and black cornicles (small tubes located on the end of the abdomen). A hand lens or microscope evaluation is most likely required to confirm physical characteristics and positive identification. The sugarcane aphid will feed on the sorghum leaves and stem, resulting in reddish colored lesions from the injury.
Management & Thresholds
To see recommendations on management from Dr. David Buntin, visit my previous blog post: Managing Sugarcane Aphids In Sorghum.