Rauschkolb and Mikkelsen (“Survey of Fertilizer Use in California- 1973,” UC Division of Agricultural Sciences bulletin, forthcoming) estimated common fertilizer application rates and percentages of land fertilized by area for individual crops in 1973. We derived weighted statewide application rates from these estimates. Thus, our estimates of application rates are based on the cropping pattern existing in 1973. A significant change in the location of crop production in California could produce a substantial change in fertilizer use without any change in fertilizer prices or planted acreage.

The authors thank John Yoakley, Entomology student, UC, Berkeley, for assistance during this field study and Fred Charles, Pest Management Consultant, West Point, California for providing the pheromone trap records. Part of this project was supported by the Extension Service and the Animal and Plant Health Inspection Service (APHIS) of the United States Department of Agriculture.