Former graduate research assistant. Current address: Winstrip, Inc. Rt. 2, Jeffress Road, Fletcher, NC 28732.
Received for publication 30 Nov. 1987. Paper no. 11200 of the Journal Series of the North Carolina Agricultural Research Service, Raleigh, N.C. From a thesis submitted by R.R.M. in partial fulfillment of the requirements for the PhD degree. We acknowledge the Fred C. Gloeckner Company and the Fred C. Gloeckner Foundation, Inc. for their support in this project. Use of trade names in this publication does not imply endorsement by the NCARS of the products named, nor criticism of similar ones not mentioned. 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.