Our river birch has been attacked fiercely by caterpillars. We've never had this problem before (in the 3 years we've had it). They are defoliating the tree fast! Is there anything we can do about it at this time of year? Is there a preventative we can do next spring? It's in a breezy spot and is getting quite tall, so spraying could be difficult. But we want to hear all solutions! Thanks. Barb R
