When eggs laid on the leaf stem hatch, emerging larvae tunnel through the leaf down into the stem. Working their way down the stem nearly to the soil line, the larvae girdle the stem and build protective plugs of frass, a sawdust-like material. This feeding damage so weakens the plant stem that wind can knock the whole plant to the ground. Harvesting soybeans from horizontal plants is nearly impossible. Dectes larvae overwinter in soybean stubble beneath their plugs of frass.
Adults emerge in summer to lay more eggs, beginning the cycle anew.
In Delaware, this innocuous-looking little bug has defied control efforts. Also, cultural practices that are effective in controlling other types of bugs don't work on Dectes. Biocontrol is not an option because Dectes has no known natural enemies. Although crop rotation is effective, droughty soils without irrigation preclude growing other crops such as field corn. Plowing an infested crop under in the fall kills the larvae, but invites soil erosion, a serious problem in this area.