By John E. Preece, Paul Read
By Henry Hobhouse
By Haslam
By Honychurch, Penelope
By PETER DAVIS
By H. Smith
By John H. Dodds, Lorin W. Roberts
By Edward Knobel
By Agnes Chase
By B. Verdcourt, E.C. Trump
By Tompkins, Peter, Bird, Christopher
By Nicholas Harberd
By Richard H. Zimmerman, Robert J. Griesbach, Freddi A. Hammerschlag, R.H. Lawson
By Elgene E. O. Box
By James L. Brewster (Horticulture Research International, Wellesbourne, UK)
By Christian Broutin
By N.T. Gill, K.C. Vear
By G.Clifford Evans
By Food and Agriculture Organization of the United Nations
By Hazim S. Daoud
By Thomas, E., etc.
By P. S. Nutman
By RA Lelliott (Dunez, Head of the Plant Pathology Station, INRA, Bordeaux; D.), D. Stead
By W. Heydecker
By HARVEY MOTULSKY
By Hugh Johnson
By Keith Rushforth