Late varieties appear to be more susceptible than early ones, but aphids aren't expected to be an annual problem. When they are, effective insecticides are now available whenever favorable crop conditions warrant use.
Lilly, J. H.
"What About Aphids on Sorghum?,"
Iowa Farm Science: Vol. 13
, Article 5.
Available at: https://lib.dr.iastate.edu/farmscience/vol13/iss1/5