Your tree has a scale insect, the small, brown, shiny, rounded bumps on the stems and twigs, most likley Lecanium scale. On young trees they can weaken the tree but generally don't pose a serious problem to large mature trees. They can be somewhat challenging to control due to the waxy shell they hide under. The best time to control them is when the crawlers are active. Other methods can be used to control the overwintering insects and the scales, such as the use of horticultural oils. Systemic insecticides can be somewhat helpful.

This link takes you to a document describing the insect and what to do to control it (scroll to the last couple pages) - https://extension.okstate.edu/e-pest-alerts/site-files/documents/2003/wheat-disease-update-may-23-2003.pdf. This link takes you to a fact sheet with additional insecticide recommendations for control - Ornamental and Lawn Pest Control (For Homeowners).

In addition to the scale insects, it might also have anthracnose affecting the leaves. Anthracnose is a fungal disease that usually ocurrs in the spring when weather is mild and wet. It can be controlled with fungicides labelled for anthracnose applied at the time of leaves emerging in the spring. Usually this disease does not pose a threat to healthy trees and it becomes inactive as we get into the hot summer months. Remove fallen, infected leaves, especially this fall and destroy. Be prepared to apply a fungincide next spring if we have mild, wet conditions. 

This fact sheets provides more information about anthracnose and other foliar diseases of deciduous trees - Anthracnose and Other Common Leaf Diseases of Deciduous Trees. If you want to confirm that the tattered leaves are due to anthracnose, you can submit samples to the Oklahoma County OSU Extension Center for diagnosis - https://extension.okstate.edu/county/oklahoma/.

Always read and follow all pesticide label directions.