Q.avocado tree losing its fruit
My tree looks healthy and starts to get small pea-sized fruit then inside of a week all the fruit are gone, not fallen off…. gone. Do birds, squirrels etc. get it? How do I prevent animals from taking it? Also, what kind of insecticide should I use for the bugs? I live in so. California. Thank you for your help.
Tim

The kind of insecticide you use depends on which insects are afflicting your avocado tree. I would recommend you read the following article for insect identification and course of treatment:
https://www.gardeningknowhow.com/edible/fruits/avocado/avocado-pests-and-diseases.htm
Squirrels, raccoons, opossums, field mice and rats will chew avocado fruit in any stage of development.
You can try filling drawstring mesh bags with mothballs or wrap mothballs in a cheesecloth secured with a rubber band. Hang the mothballs on the branches of the avocado tree. Replace the mothballs when they lose their scent.
To deter squirrels in the daytime you can dangle CDs in the branches. You can also try giving the squirrels an alternate food source located away from your tree to minimize the number of snatched avocados.
Here is an article with ideas on how to squirrel proof your fruit tree:
https://www.gardeningknowhow.com/edible/fruits/fegen/squirrel-proof-fruit-trees.htm
An article on raccoons:
https://www.gardeningknowhow.com/plant-problems/pests/animals/getting-rid-raccoons.htm
...and one on opossums:
https://www.gardeningknowhow.com/plant-problems/pests/animals/possum-control.htm