Thirty-one species of Acacia were quantitatively evaluated in the field at San Jose, CA, for resistance to the acacia psyllid, Psylla uncatoides (Ferris and Klyver). This insect causes foliage necrosis and dieback of the tips of susceptible Acacia. A few species exhibited no infestation by the insect, many were found highly to moderately resistant, and several were confirmed highly susceptible. Propagation and use of horticulturally desirable species of Acacia, locally adapted and with high resistance to the psyllid, are recommended where this pest occurs.
2Present address: Moore Entomological Consulting, Berkeley, CA.
3Address: Saratoga Horticultural Foundation, Saratoga, CA.
4The authors are grateful for the assistance given by Thomas M. Kretchun, Superintendent, Deciduous Fruit Field Station, San Jose, CA, in the maintenance of the Acacia planting.