Susceptibility of various hybrid poplar clones to attack by Malacosoma disstria larvae was assessed. No-choice experiments were conducted on one week old foliage using first instar larvae. Performance of larvae on each hybrid was also determined. Clones 3389 (DxB), 3729 (NxM), 505508 (MxDT), 750316 (MxT), and 915320 (MxB) were found to be highly resistant to attack by first instar larvae. Susceptible clones were found to belong to the P. x euramericana and P. x generosa Henry crosses. Hybrids with a P. maximowiczii or P. balsamifera parent were found to be consumed at intermediate levels. Consumption was found to be positively correlated to survivorship and negatively correlated to instar duration; instar duration was negatively correlated to survivorship.