Feasibility Study of a Dry-Liquid Insecticide Employed in a Coniferous Forested Environment.
DESERET TEST CENTER FORT DOUGLAS UTAH
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The U.S. Forest Service and Deseret Test Center DTC conducted a test in the Nezperce National Forest, Idaho June 1971. This test demonstrated the feasibility of controlling the spruce budworm by disseminating a dry-liquid insecticide from an aircraft. The test also showed that a diurnal drainage wind is an effective transporter of small aerosolized particulates when released below the inversion layer. The rotorod sampler was effective in collecting the dry-liquid particulate of Zectran and defining the area covered. The predicted below-canopy dosage generally exceeded observed values, suggesting the need for additional information about the below-canopy environment. It is hypothesized that the low budworm mortality resulted from a low impaction efficiency of the small particles and insufficient amount of Zectran being released over the target. To achieve a 90-percent mortality rate, an estimated 10,700 to 34,700 particles in the 3.5-micron size range would be required, compared with only 3 to 10 particles in the 35-micron range. Author