Weed control studies in tomatoes, 1968–70
The development of selective herbicides has been basic to the profitable use of the mechanical tomato harvester. Weeds must be efficiently controlled if such machines are to operate effectively in California tomato fields. About 40% of California's tomatoes were treated with herbicides for annual preemergence weed control in 1965. Only five years later over twice this acreage was treated (87% in a 1970 survey). The most common weeds in tomato fields include barnyard grass, pigweed, nightshade, nutsedge, shepherd's purse, and many other broadleaf weeds and grasses.