Senior Technical Representative, BASF Corp., Chemical Division, Parsippany, NJ 07054.
Assistant Professor, Dept. of Vegetable Crops, Cornell Univ., Ithaca, NY 14853.
Received for publication 21 May 1985. 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.