As grain sorghum acres increase across the central Great Plains, more producers are required to manage the insect pressure that can occur with this crop (Figure 1). Grain sorghum is generally planted in late spring or early summer and from the onset is susceptible to insect damage from a long list of pests. Wireworms, armyworms, grasshoppers, chinch bugs, green bugs, sugarcane aphids, corn leaf aphids, common stalk borer, sorghum midge, spider mites and head worms are species commonly observed during the growing season across the Plains. Many seasons, one or more of these pests result in economic injury to a sorghum crop in this geography.
Scouting all summer long is critical when producing grain sorghum, and this effort must start at emergence. Left unchecked, many of these insect pests can cause economic injury in a short time span. Insecticides that control sorghum pests have been available for years and most are labeled for many of the same species; however, correct identification of the pest and timing of application are required. Chinch bugs, aphids and green bugs are sucking pests, while grasshoppers, head worms and armyworms are leaf and head feeding insects. Mites and midge are in separate classes.
Often sorghum fields are close to wheat fields and as the wheat begins to ripen, pests in the wheat such as armyworms or chinch bugs leave the wheat and infest the sorghum. Therefore, scout wheat fields proximate to grain sorghum fields for the possibility of pest migration.
Sorghum planted into a cover crop can be subject to the insects that were feeding on the cover crop prior to the termination of the cover crop. Scouting in this case needs to be conducted in the standing cover crop. Two very good sources for grain sorghum information include:
- Grain Sorghum Production Handbook, Kansas State University, February 1998. (https://bookstore.ksre.ksu.edu/.)
- Grain Sorghum Production Handbook, University of Arkansas. (https://www.uaex.edu/.)
Vanderlip, R., Roozeboom, K, Fjell, D., Shroyer, J., Kok, H., Regehr, D., Whitney, D., Rogers, D. H., Alam, M., Jardine, D., Brooks, H. L., Taylor, R.K., Harner III, J.P., and Langemeier, L.N. 1998. Grain Sorghum Production Handbook. Kansas State University. C-687.
Espinoza, L., Kelley, J., Cartwright, R.D., Coblentz, W.K., Gardisser, D., Greene, J., Huitink, G., Kirkpatrick, T., McLeod, P., Phillips, J.M., Scott, R.C., Smith, K., Tacker, P., TeBeest, D.O., Vories, E., and Windham, T. Grain Sorghum Production Handbook. MP 297. Cooperative Extension Service, University of Arkansas.
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