Early season stalk tunneling in sorghum may cause lodging later in the season. Which insect is responsible?

• A. sorghum midges
• B. chinch bugs
• C. sugarcane rootstock weevils
• D. sorghum headworms

Answer: (C)

Early season stalk tunneling weakens the stem’s structural strength, so as the plants grow taller and face wind or heavy grain load, they are more likely to lodge. The insect responsible for this kind of damage in sorghum is the sugarcane rootstock weevil, whose larvae bore into the stalks and create internal tunnels that girdle and weaken the stem. That internal damage is what sets up lodging later in the season, even if the external symptoms aren’t obvious early on. Other insects listed cause different problems—sorghum midges target developing panicles, chinch bugs feed on sap at the base and stunt plants but don’t create internal tunneling, and sorghum headworms feed on the grain heads rather than weakening the stalk—so they’re not the ones linked to later lodging through stalk tunneling.