Grain sorghum maturity ranges from milk to hard dough.  Sorghum fields that have not reached hard dough should be scouted for headworms and stink bugs.  And all sorghum should be scouted for sugarcane/sorghum aphids.

We have not found aphids in colonies greater than 20-40 feet in size.  Most of these are being consumed by beneficial insects such as lady beetle, lacewing, and syrphid fly larvae.

What was most noticeable this week was worms in younger sorghum fields.  The older sorghum in soft dough or beyond did not seem to have as many worms as the younger sorghum.  Fields in the milk stage or early soft dough had as many as 71 large worms (> 1/2 inch) in 100 heads.

For an economic threshold for worms, divide them into medium larvae (1/4 to 1/2 inch) and large worms (>1/2 inch). Treat when the field averages more than 1 medium worm on 1-2 heads or 1 large worm in 3 heads. Small worms under 1/4 inch no not need to be considered as they feed very little and natural mortality is very high.

Leaf-footed Bug Nymphs. Photo by S. Biles

Stink bugs and leaf footed bugs are being found in sorghum fields, but many of the fields we have looked at have either been treated or are below threshold. Treat a leaf-footed bug as a stink bug.

Sorghum Headworm Economic Threshold Calculator here: https://extensionentomology.tamu.edu/sorghum-headworm-calculator/