Photos please. Sounds like Phytophthora Canker to me, but we would need photos to be able to correctly ID the issue. Where on the trunk are you seeing this lesion? Down towards the soil line? If you can take a few photos, both a bit aways from the tree for perspective, then close up, that would be helpful.

Patty S.

Here is a link that might be useful: UC IPM: Canker, Crown Rot

Thanks Patty. S i will get photos up ASAP.

Tree is along my fence line next to a rose bush and boganbillia

Scab

I rotated the picture.

I would say this does look like canker to me. Joe, does your avocado's tree trunk get sprayed by your lawn sprinklers by chance? If so, adjust your lawn sprinklers so they do not hit your tree. You'll want to eliminate any possible causes of canker. And, follow the directions from UCIPM in how to treat it. You can also call your local ag agent or, if you have a good orchard supply store near you, they should also be able to advise you and have the proper products to treat this. I'm not sure where in S. Calif. you live, but if you're in N. San Diego county, Grangetto's would be the place to go for further advice and products.

Patty S .

Im in the south bay area near eastlake. Ill check my local nursery. Thanks for the help. I appreciate it.