Hi Tim,

This almost looks like bird damage. Most bugs don't create such big wounds in fruit. Are many apples affected?

If you have worms, they're likely apple maggots. Preventative measures are discussed here:

https://extension.umn.edu/yard-and-garden-insects/apple-maggot

If you choose to bag, do so when the apples are grape-sized. Here's how it works

1. Cut the bottom corners of the baggies off. This will allow moisture and rain water to drain.

2. Look for apples that have no scars or marks. If two or three apples are growing in a cluster, choose the best one and pull off the others.

3. Open a baggie, and slip the apple inside, taking care to keep leaves out of the bag. Press the seal on the bag closed from either side of the apple.

4. To make sure the baggie doesn't fly off the tree over the summer, secure it by stapling the closed bag at the top on either side of the fruit stem.

Hope this helps. Good luck!