Question
We live in the desert of Tucson, Arizona, and have a large, mature, African sumac tree. We recently noticed that a very large limb on the tree has all the bark removed in a ring around the limb that has been girdled by tiny, black-to-brown sap-producing holes. There are several similar holes lower on the limb, but nothing yet on the other limbs or primary trunk. There is plenty of literature on conifer bark beetle problems in the surrounding mountains, but do bark beetles attack sumac trees in the desert and what can we do about this? We'd hate to lose this tree. thank you.

Answer
The bark beetles in the conifers do not attack any other tree species. There maybe a bark beetle on Afc. Sumac but I could find no reference so if there is it causes no problems. bark beetles leave no holes in the bark so it does not sound like beetles.

Sounds like it maybe a woodpecker called the sap sucker. They make hole in the bark and when insects come to eat the sap the bird returns and eats the insects. Not a real large problem but the birds can be discouraged by spraying an insecticide on the area and this will will or prevent insect attack and the birds will go away. I would use an insecticide called Merit this will be absorbed by the bark and IF for chance there were insects in the bark the Merit would kill them.