All of Ventura county's 2,900 acres of avocados is in the southern half of the county, with the majority in the Santa Clara Valley-Oxnard Plain and the Las Posas Valley-Camarillo areas. Most of the avocados are growing in 17 different soil series, but over 25 soil series are involved. Fortunately, avocado root rot has been found in only 21 locations and has damaged a total of only 21 acres. Since many avocados are growing on restricted or poorly drained soils, it is fortunate that the root rot fungus, Phytophthora cinnamomi, has not been spread very widely in the county.

W. A. Thorn, S. M. Mircetich and S. Hashimoto, U. C., Riverside; and R. M. Rust, Soil Conservation Service, Moorpark, also co-operated in this survey.