avocado tree showing a white powder like substance on branches

Hi, i have an avocado tree that is about 15 years old, healthy, the ground has good drainage and give fruits every year. The last week a couple of spots started to appear on some branches with a growth on thrm of white powder like substance that crumble under light touch. What can it be?

Hi Dan, welcome to the forum.

The symptoms look like shot hole borer infestation. If you look closely, you will find a tiny entry hole in the center. The beetles also carry the fusarium fungi that feed on the sap and wood around the wounds and give rise to the white circles spreading from the entry hole. Eventually the infected branches will die back. Are you in California? Maybe your local university extension office can offer advice on the treatments.

I cleaned one of the spots, i cant seem to find a hole created by a bug. Im in israel

Is there something gumming in the center of the crack? Dusty stuff can be the frass of the pest. If it is a soft bodied larvae,  maybe you can poke in the crevices with a wire to kill it.  Disinfect the area and see how the tree's recovering.