–by Jeff Whitworth — Field Crops
Sugarcane aphids are still quite active throughout the eastern 2/3rd’s of Kansas in fields that still have some green leaves. These aphids are continuing to migrate in and almost as soon as they land on green leaf tissue, they start producing the tiny nymphs (see fig 1-just produced nymphs with winged female that produced them). These aphids are still infesting sorghum but, so far, have not caused any problems throughout northcentral Kansas. It is getting late enough in the growing season that they should not have enough time to increase to the point where they will be a problem.
Figure 1: SCA nymphs and mother (photo by Cody Wyckoff)
Figure 2 shows an area outlined by a marker, on the underside of a sorghum leaf that was infested by a substantial (200+) colony of sugarcane aphids in early September but was subsequently eliminated by natural causes-no insecticides. This has been typical for the last 3 years, i.e. sugarcane aphids migrate into Kansas, starting in about mid-July and continue until late October, and establish small isolated colonies but with very few areas actually developing significant populations that require treatment.
Figure 2: Underside of leaf previously infested by SCA colony (photo by Cody Wyckoff)