Greetings Rhonda,

The most common condition by far that causes worms in apples is the codling moth. The best options for chemical control of codling moth are:

-Acetamiprid

-Insecticidal soap

-Kaolin

-Spinosad (Entrust)

-Cyd-X

All of the above are effective and non-toxic to bees. Follow the exact directions on the label of the product you decide to use for application.

You will want to spray 10 days after all of the flower petals have fallen off and you will likely need to spray multiple times, once every 7-14 day. The label of the product you select will specify how often. The goal is to spray when there are eggs and newly hatched larvae before they begin to burrow into the apple.

Another very effective method of prevention is to remove all fallen leaves and fruit from around your apple trees.

If you would like more information, there is a great OSU Extension article on fruit tree pest management you can read here:

https://extension.oregonstate.edu/gardening/berries-fruit/fruit-tree-pest-management

Happy gardening,