Insects and disease organisms are a continuing threat to cottonwood (Populus deltoides Bartr.), especially during the tree's first 5 years. The danger is intensified in large plantings of a single species and age because rapid buildup of damaging agents can occur. This booklet, will help forest nurserymen and plantation managers identify and control pest problems. The major insects and diseases are illustrated; and information on their importance, signs of infestation, biology, and natural control is presented. Brief mention is made of other pests which may be of local or sporadic concern. A list of registered chemical controls is also provided. This list is subject to change as new materials are approved, and revisions will be made available at periodic intervals.