Received for publication 24 Mar. 1988. The use of orchards belonging to Jerry C. Hockman, William H. Kilmer, and Virgil Maphis is gratefully acknowledged. The research reported here was supported by the West Virginia Agriculture and Forestry Experiment Station and is published as scientific article no. 2111. The cost of publishing this paper was defrayed in part by the payment of page charges. Under postal regulations, this paper therefore must be hereby marked advertisement solely to indicate this fact.