There are several genera of native bees which may be observed in alfalfa fields in Arizona. Their populations in recent years have been reduced as their nesting sites have been eliminated by the more thorough cultivation of fence rows and ditch banks and by the use of highly toxic insecticides. Observations made in Arizona alfalfa fields over the past eight years have indicated that, except in a few isolated cases where small acreage has been involved, native bees have never been present in sufficient members to assure adequate pollination of the alfalfa.
Butler, George D. Jr., "Observations of Native Bees in Maricopa County Alfalfa Seeds Fields" (1961). Bu. Paper 60.
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