Q:Β We have sweet acacia trees at the entrance of a property in Chandler that are having severe limb breakage and dieback lately. It looks like borer signs and Iβm wondering if there is a good alternative tree I can recommend to the HOA board. Would a Red Push Pistache work well here? There are also a few ash trees that are showing similar signs throughout the same neighborhood. Do you think this could be caused by the same borer/pest?
A:Β The acacia tree in your photos is indeed suffering but in this case the borers are likely only a symptom rather than the cause. The holes indicate flat-headed borers and most species in this family of beetles are attracted to dead and dying trees. I recommend checking the history of irrigation practices for these trees. The species you mentioned should be receiving water every seven to 14 days during the summer to a depth of 24 to 36 inches. You can back this off to once every 10 to 21 days in the spring and fall, and every 14 to 21 days in the winter. The red push pistache is a good substitute as long as there is space for its mature size. It would likely have the same issue with irrigation if that were the problem so it would be good to address that before replanting. Since different tree species have somewhat different pests, it would be difficult to say the ash trees are having the same problem without seeing them.
Peter L. Warren is the urban horticulture agent for the Pima County Cooperative Extension and the University of Arizona. Questions may be emailed toΒ tucsongardensage@gmail.com
