Technical Abstract: The hypothesis that larvae of Cerotoma trifurcata do not injure the roots of soybeans (Glycine max L.) was tested in the greenhouse. Pots containing individual plants were either not infested or infested at high (19 larvae per pot) or low (5 larvae) levels. After 3 wk, the plants were dissected and the fresh and dry weights of the roots and shoots were recorded. Also, the number of nodules, number of damaged nodules, and the area and volume of nodules were compared among the treatments. Nodules were the only root system organ visibly damaged by larval feeding. External nodule surfaces were scarred, and frequently the internal matrices of the nodules were completely excavated by the larvae. Significantly more nodules per plant were found in the infested treatments, and damaged nodules were significantly more abundant on plants in the high infestation compared with those in the low infestation treatment. Also, plants from the high infested treatment had significantly smaller nodules than the uninfested control, suggesting that the infested plants responded to larval damage by producing additional nodules. The implications for larval infestation to soybean production are discussed.