No simple reason and I think not really well understood. But excessive heat and perhaps water stress seems to play a role. It doesn't seem like you would have much of either.

It's common in cherries in some areas. I haven't had much on anything except Flavor Supreme pluot. It has about 50%. Other pluots have none. So very variety specific.

This post was edited by fruitnut on Fri, May 23, 14 at 15:57

Thanks Fruitnut. The 'twins' are on my 'Now I don't know the variety Peach (thought was a Belle of Georgia' happy to know its not!). I've removed at least thirty so far. Will go out tonight and look for more. Thanks again, Mrs. G

Mrs. G,

In good years, doubles (siamese twins) are one of the first peaches to remove at thinning (that and peaches low in crotch angels).

However, when peaches are lean, we leave the doubles on. Later, after they get some size, you can carefully break off one of the doubles. The remaining peach will heal, if the separation is early enough. The peach won't be flawless, but will still look decently attractive and will taste as good as any other.