Grain sorghum is resistant to corn rootworms, but may be attacked by corn earworms, aphids, and greenbugs. Combining time will depend on the fall weather and the availability of grain drying facilities. Sorghum grain can be threshed free of the head when the seed Moisture is 20-25 percent. The seed is physiologically mature at even higher moisture levels. Frost will generally kill the top of the plant and help to lower the moisture content.
Some hybrids have a loose, open type head which hastens field drying.
Sorghum seed is easily damaged in the threshing operation, especially when the grain is dry. The combine platform should be operated as high as possible to minimize the mass of stems entering the combine. If necessary, the cylinder speed can be reduced to one-half that used for wheat to prevent cracking the seed. However, grain moisture will normally be higher and faster cylinder speeds can be used. The recommended cylinder speed is 750-1300 R.P.M. but loss determinations should be made to refine the combine adjustments.