Frankly, we would prefer that you either let it die, or have it cut down. Please see this article from the Plant Conservation Alliance Alien Plant Working Group on Chinaberry. The Lady Bird Johnson Wildflower Center, home of Mr. Smarty Plants, is committed to the growth, propagation and protection of plants native not only to North America but to the area in which the plant is being grown; in your case, Pima County, AZ. In addition to being non-native, it is extremely invasive because of the proliferation of seeds from the tree, some airborne by birds who eat the berries and take the seeds somewhere else to be invasive. And, since it is non-native, we would have no information on diseases and disorders it might have.