Adapting to the Land by John F. Freeman & Mark E. Uchanski

Author:John F. Freeman & Mark E. Uchanski [Freeman, John F. & Uchanski, Mark E.]
Language: eng
Format: epub
Publisher: University Press of Colorado

Figure 5.4. Flood irrigation, Longmont, 1963. Courtesy, Agricultural and Natural Resources Archive, Colorado State University Libraries, Fort Collins.

As with inorganic minerals used for fertilizer, natural herbicides and insecticides had long been used by agriculturists. Recall that early Greeley-area farmers used Paris green (arsenic) against potato beetles; Bordeaux mix—copper sulfate and lime—helped protect cantaloupe vines in the Arkansas Valley. Plant-based rotenone, also developed in France but recently banned, had been used as a pesticide by farmers against cabbage worms and other leaf-eating larvae. In addition, the practice of rearing “good bugs” in captivity and then releasing them in orchards to control “bad bugs” had been known for centuries. In the early 1940s, the Colorado Department of Agriculture had established the Palisade insectary, which over time became a significant source of information for agriculturists seeking to reduce their reliance on chemicals. Strategically located in orchard country, the insectary began by growing the plants for and then raising the insects that feed on pests such as the fruit moth, expanding to insects that feed on noxious weeds such as leafy spurge and field bindweed. To date, biological products alone remain insufficient in supply and too costly to control weeds and pests on the more than 36 million acres of the state’s cropland and rangeland.

DDT had emerged postwar as the insecticide of choice, although quantities were limited and costs remained relatively high. As a result, to cope with grasshopper infestations in Baca County, agent James E. Hughs spent more than a month in the spring of 1949 operating a mixing station. He reported using 20,000 pounds of sodium fluorosilicate, one railcar load of bran, and three loads of sawdust. Great care had to be taken in handling the white granular powder, which irritated eyes on contact and caused breathing problems when ingested. Ranchers whose properties adjoined the national grasslands asked Hughs to intervene on their behalf by requesting that federal officials bait the grasslands. Government officials declined the appeal on the grounds that the offending grasshoppers were identified as native; the density of 10 to 15 grasshoppers per square yard was less that the officially set epidemic level of 24 or more per square yard. Officials did, however, assign personnel and spray equipment to areas invaded by migrant grasshoppers at the epidemic level. As drought conditions worsened, epidemic levels reached up to 300 grasshoppers per square yard in Cheyenne County, which became the site of the first massive aerial spraying of DDT. Decommissioned four-engine B-17 bombers conducted early morning runs over 271,000 acres. In 1958 state and federal agencies collaborated with local agencies and ranchers in spraying more than 3 million acres statewide, considered the largest spraying project in the world to that date.27

Just as DDT had become the preferred choice of insecticide, dichlorophenoxyacetic acid (2, 4-D) became the leading herbicide, introduced commercially in 1945 by the Dow Chemical Company. Known as a synthetic auxin, 2, 4-D is a chemical compound that causes plant cells to divide and grow without stopping, burning more energy than they can make by photosynthesis and killing plants by over-stimulating them.

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