Ovipositional behavior, viability of eggs, and growth and survival of the young larvae of Oulema melanopus (L.) were adversely affected by the density of pubescence of wheat leaves. Gravid females were reluctant to lay eggs on densely haired leaves, and the number of eggs laid was significantly reduced by greater density of pubescence. Eggs laid or placed on leaves with dense pubescence were susceptible to desiccation, and less than 10% hatched. Only 20% of the first-instar larvae restricted to densely pubescent leaves were alive after 3 days. Also, young larvae restricted to wheats with dense, moderate, or slight pubescence, or glabrous wheats, gained significantly less weight as the number of hairs increased. Third-instar and fourth-instar larvae used wheats with greater pubescence more efficiently than did younger larvae.