Declining root systems comprise one of the most serious problems in southern California in citrus production and fruit size. Therefore, a station-wide citrus rejuvenation project was initiated in 1953.

The above progress report is based on Research Project No. 1612, a station-wide project administered by R. C. Baines, Plant Nematolo-gist; H. D. Chapman, Professor of Soils and Plant Nutrition; J. C. Johnston, Farm Advisor, Riverside County; L. J. Klotz, Professor of Plant Pathology; R. L. Metcalf, Entomologist; P. W. Moore, Specialist in Citrus Grove Rejuvenation Research; S. J. Richards, Associate Irrigation Engineer; and W. B. Sinclair, Professor of Biochemistry—all of the University of California, Riverside.

Lewis H. Stolzy, Assistant Irrigation Engineer, University of California, Riverside, cooperated in the irrigation studies.

The application of the soil fumigant and evaluation of citrus nematode control were made by R. C. Baines, Plant Nematologist, University of California, Riverside.