Received for publication 21 February 1978. 1Broom's Barn Experimental Station, Higham, Bury St. Edmunds, Suffolk, England. 2 Department of Nematology, University of California, Riverside, California 92521. 3Farm Advisor, Cooperative Extension, Santa Maria, California 93456. 4 Farm Advisor, Cooperative Extension, El Centro, California 92243. Much of this work was done while the senior author was...
