Question
I have an arizona cypress that is beginning to turn brown at the top. I found a place near the top that looks like some kind of critter has bored in to the trunk. Can I save the tree?

Answer
Sounds like an insect called a tip moth. The adult moth lays its eggs on the tip bud of a branch and the egg hatches and the small larvae bores into the tip and down into the stem. It feeds there and completes it life cycle. The tip of the branch dies. The tree will put out a new leader causing the tree to bush out at the tip. I would treat the tree with an insecticide called Bayer Advanced Tree and Shrub Insect Control. This is applied to the spoil and the roots take it to the foliage and stems killing the feeding insects when the feed on the plant juices with the insecticide. The old dead tips can be cut off and then destroyed removing the insect in the twig. Sprays of insecticide can be used but they must be applied before the moth larvae enters the twig or the insecticide will not work. This timing is difficult to get right so the soil applied insecticide is best in this situation,. Here is a web link to more information on this product. Check with your local garden type or nursery for this product. http://www.bayeradvanced.com/insects-pests/products/12-month-tree-shrub-insect-c...