Apples

The poster formerly known as... says...
Looks to be codling moth damage. There will be a big worm inside eating the fruit and then pooping this stuff out the hole in the side of the apple... You can get traps for them, but at this late stage you've probably lost most of your crop. Unaffected ones can be covered in paper bags, pantyhose lengths or whatever to exclude the moths from laying their eggs in the fruit.