redcThe hills have been dry for a long time, and the long dry fall is bringing animals into the avocado groves that normally stay out in the hills. They want the green cambium of trees and the moisture it provides. And especially rodents will have a field day in the well-maintained orchards.

Gophers are not usually a problem in mature avocados. They will often chew the bark below ground. Ground squirrels when they get hungry can go after just about any part of the tree, trunk branches and fruit. Voles or meadow mice will go after bark about 2 inches above ground.  Rabbits can take out bark up to a foot above ground.  This bark damage often leads to the yellowing of the canopy and if damage is extensive enough, wilting of the canopy.  Growers don't normally see the damage until they see the wilted tree and start looking for the problem.  If healing along the margins of the damage is occurring, it means it was damage that was done previously.  If margins are still ragged, it means the beasts are still enjoying the tree.  Trapping, poisons and a busy Jack Russell terrier are all effective, especially if used together.  Voles especially like mulch around the base of the tree, and should be pulled away a foot to 18 inches.  They make tunnels thought the mulch which then becomes a diagnostic for identifying the cause. 

It's not just avocados that are ravaged by these animals. Citrus is like candy to them and then there's all those acres and acres of almonds that have been planted.

Avocado canopy collapse.  Why?  Check the tree out.  See the red squirrel feeding stations in the background?

Damage that is healing over.