Received for publication 24 June 1983. Florida Agricultural Experiment Stations Journal Series No. 4455. Mention of a proprietary product does not constitute a guarantee or warranty of the product and does not imply its approval to the exclusion of other products that may also 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.