Associate Professor. Present address: Coastal Research and Education Center, Clemson Univ., 2865 Savannah Hwy., Charleston, SC 29407.
Received for publication 9 Dec. 1985. Journal Article no. TA 21206 of the Texas Agriculture Experiment Station. Mention of a trade name or proprietary product does not constitute a guarantee or a warranty of the product by Texas A&M Univ. and does not imply its approval to the exclusion of other products that may be suitable. 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.