Cicada Damage to Ash Trees May Be Confusing

Q.  Several years back my father and I planted two Raywood ash trees in each of our yards. Now both of trees have longitudinal gashes along the stems that kill many of the smaller branches. Last year I  found the same problem on one of my rose bushes. Per the recommendation of the nursery I sprayed a systemic containing imidacloprid and clothianidin on the trees.

My picture showing cicada damage to small stems on Acacia.

A.  This sounds like egg laying damage by the Apache cicada; those high-pitched insects you hear buzzing in about July. The insecticide you are spraying will not correct this problem so stop using it.

This female cicada is not laying eggs...yet..

            Apache cicadas make that buzzing noise so they can mate. Once they have mated, the female lays eggs in a slit she creates on the branches. If these slits cause enough damage, the twig dies. The eggs then hatch, and the insect drops to the ground where they burrow into the soil and feed on plant roots. Lots of different trees are favorites, your ash trees (sounds like the roses, too) being among them.

Cicada empty skin or exoskeleton left behind on anything they can find when they emerge from the ground.

            Spraying the tree with an insecticide, or drenching the soil with one, is not a good idea. I think your best bet is to give your trees as much chance to heal themselves, after the damage is done, as possible. Their best chance of healing from this type of damage is the presence of fertilizer in the soil and adequate water during the heat. Of course, scaring these insects off to other trees during mating time would help.

            Make sure these trees are fertilized in the spring and bump up the amount of water applied when you start hearing the buzzing noise. You might even try watering every other day during this period to help the tree recover from cicada egg laying damage.