This subseries comprises materials relating to William McPherson’s involvement in the avocado industry. All but one folder consists of correspondence addressed to McPherson, both as a private individual--including receipts and accounts of McPherson’s participation in the California Avocado Growers Exchange / Calavo Growers of California--and in McPherson’s capacity as Secretary of the California Avocado Association in 1927/1928 - 1929/1930, and as Secretary of District 3 of the Calavo Growers of California in the early 1930s. The file for 1931 includes the manuscript and typescript of McPherson's talk on C. P. Taft, given before the Growers Institute, 9 June 1931, and published in the California Avocado Association Yearbook for 1931. The subseries also includes two notebooks with McPherson’s jottings on various matters relating to the avocado industry.