Sugarcane aphid update
(Note: The following is from the K-State Department of Entomology blog site, dated August 2, 2016. See: http://blogs.k-state.edu/kansasbugs/2016/08/02/sugarcane-aphid-expanding-to-other-counties-in-kansas/ – Steve Watson, Agronomy eUpdate Editor)
Sugarcane aphid has been confirmed in the following counties in Kansas: Marion, Sedgwick, Sumner, Cowley, Labette, Meade, Haskell, and Ford. Populations first reported in Sumner and Cowley counties have reached threshold levels (30% of plants infested with visible signs of honeydew on leaves) and are being treated with insecticides. Scouting fields early will help determine the need for an insecticide application before losses occur. Treating too soon may increase the need for additional insecticide treatments later, as populations can rebound based on immigration events. Scout often, as densities can change quickly. Report any infestations in new counties to your local agent or by using http://myFields.info.
Figure 1. Counties in Kansas confirmed with sugarcane aphid in green, as of August 2.
Recommended treatment options for SCA control are either Transform (Dow AgroSciences) at 1 oz per acre, or Sivanto prime (Bayer CropScience) at 4 oz per acre, applied in 15 – 20 gal of water from a ground rig. Application from the air will be more costly and less effective, as it will not permit application of these materials in sufficient volume to obtain the coverage necessary for good efficacy. The cost per acre is lower for Transform, and this material is also the least toxic alternative for aphid natural enemies.
If headworms are present in damaging numbers (1-2 per head or more, the majority still less than 1 inch long), Blackhawk (Dow AgroSciences), Prevathon (Dupont) or Belt (Bayer CropScience) are alternatives that can be considered for controlling them. Note that Belt registration has just been revoked by the EPA, but existing stores may be used. Of the materials labelled for headworm control, these are the ones likely to have the lowest impact on beneficial species assisting with aphid control.
We have found Prevathon to be compatible with Transform in a tank mix; all other combinations should be tested first for compatibility by mixing small amounts in a jar to ensure no precipitate forms. Read the label carefully before you spray.
For more information, see “Sugarcane aphid scouting and management on sorghum for 2016” in the July 22, 2016 issue of the Agronomy eUpdate, No. 581.
Brian McCornack, Extension Entomologist
Sarah Zukoff, Entomologist, Southwest Research and Extension Center
Jeff Whitworth, Extension Entomologist
J.P. Michaud, Entomologist, K-State Agricultural Research Center-Hays