Hi there Bramblebee ... I don't know about your ant problem but found a site geared to orchard and fruit growers that may be of help to you.

http://forums2.gardenweb.com/forums/fruit/

I know nothing of growing fruit trees either, but I do remember coming across an article some time back about a bacterial blight of trees...

Other than the ants, do your trees appear healthy? It may have nothing at all to do with your own, but there was something about ants and other insects feeding on 'ooze' (for lack of a better word) created by the bacteria...Just a thought.

When you see ants on fruit trees they are usually after something. Sap that may be oozing out of a wound maybe caused by a sapsucker or the secretions left behind by aphids. Ants won't harm your tree. Cheers, Banana Joe

cut off a piece and bring it to your nursery.

you may just have to wash off the ants, and use some tangle foot at the base of each tree to keep the ants from climbing up it again.

you wrap some stretch tape (the stuff you use to train/tie climbing roses to a trellis) around the base of the tree, then paint on the tangle foot (its a sticky paste the ants can't climb past) on it. you have to reapply every year.

good luck.

Thanks for the help-- the tanglefoot worked wonderfully, keeping ants at bay.

Now we can all turn to the problem of aunts attacking apple trees.