Applications of iron to the soil, or in the irrigation water, have generally not been commercially satisfactory for treating iron deficiencies in lemon trees. Foliar sprays of available iron materials presently show the most promise. In one large-scale trial on mature lemons near Oxnard, yearly low-volume sprays of three iron compounds have shown increases in yield and fruit size. Leaf analysis for iron was found to be a poor indicator of response. A completely satisfactory method of correcting iron deficiency in lemons is still not available.

Kenneth Gray, ITT Rayonier, Shelton, Washington; James Davis, Lefingwell Chemical, Santa Paula; James McKelvie, Niagara Chemical, Santa Paula; Robert Austin, Geigy-CIBA, Los Angeles, and Robert Needham, Pacific Pest Control, El RW, California, supplied chemicals and assisted with these trials. U.C. Agricultural Extension Soils and Water Specialist Roy Branson assisted with the manuscript, and Farm Advisor Robert Brendler provided statistical assistance.