Any time now you should buy the Apple moth traps sold by most Garden centres
and hang one in your apple trees. We use one trap for every three trees. These attract the male moth who gets trapped in the glue in the trap and thus cannot fertilise the female so she does not lay her eggs. Also if you have a bad infestation it is worth spraying the tree in February with Winter wash. then again you could also look out for the insect trapping bandages which are fastened round the truks of the trees.