Weed costs for the state's 110,000 acres of almond orchards totaled $1,160,000 in 1964, according to estimates by the California State Chamber of Commerce Weed Control Committee. In the same year, a survey by the Agricultural Extension Service indicated that 88% of almond orchard weeds were annuals and 12% perennials. Most of the cost of control has been for machinery and hand labor necessary to control the weeds in the tree row. Continued disking has also frequently been injurious to both roots and trunks of young trees.

Assistance with these studies was also obtained from Clem Meith, Farm Ad visor, Butte County; and Don Rough Farm Advisor, Sun Joaquin County. The Geigy Chemical Co. contributed financial support to the project.