Pest description and crop damage Jointworm is the larva of a wasp resembling a small, winged black ant. Larvae live in stems and feed on sap, causing hard, woody galls usually above the second or third joints. They attack only wheat. They have not been observed as a pest for many years.
Follow practices which lead to vigorously growing, strong stands of wheat. Deep plowing in late summer or early fall is suggested in situations where this practice can be followed.
Insecticides have not been effective against this insect. Insecticide control is not recommended.