Graduate Research Assistant. Present address: 309 Creeks Edge, Chapel Hill, NC 27514.
Research Plant Pathologist.
Received for publication December 4, 1982. Published as Technical Paper No. 6594 of the Oregon State University Agricultural Experiment Station. The authors gratefully acknowledge the support of the F.C. Gloeckner Foundation. Mention of a trade name does not constitute a guarantee or warranty of the product by Oregon State University or the U.S. Dept. of Agriculture or an endorsement over other products 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.