Identify Annona and observation on the Sugar apple borer.

[CTMIAMI]

I have been observing Annonas for the last few months.

1. The Picture below are from a tree in a friend's orchard.  He does not know what it is, it was there before he got there. Is a very dark mauve color almost black. Can you guess if it can be identified?

2. The other green squamosas on the premises have a small winter crop, but about 40% of the fruit got mummified by the borer.  I have been noticing this a few times I have seen this mauve tree, it has no mummified fruit.  Are the people growing mauve squamosas notice less incident of the borer in them vs the greens?  Or this is just a fluke?