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Effect of rodding tips and soil types on distribution of selected insecticides and a water soluble dye when applied for subterranean termite control
Abstract
Distribution patterns of three insecticides and the validity of using a water soluble dye to estimate insecticide distribution in two soil types after rodding were investigated. The effects of soil type (sandy loam (SL) and silty clay loam (SCL)), and four application tips on insecticide distribution were determined. Three insecticides (0.05% imidacloprid, 1.0% chlorpyrifos, 0.5% permethrin AI, 6.06 L application quantity) were applied with a rodding tool to a 1.22 m depth at a pressure of 172.4 kPa. Neither application tip nor soil type influenced insecticide distribution, which can be described as an inverted "T" pattern. The largest insecticide concentrations were located in soil within 0.15 m of the injection site at a depth of 0.0-0.61 m and 0.25-0.40 m from the injection site 0.61-1.22 m below the surface. Generally, smaller quantities were detected in soil more distant from the injection point. Spacing of rodding holes 0.15 m apart is necessary to provide a continuous soil insecticide barrier from 0.0 to 1.22 m beneath the surface along a structure's foundation. Spacings of 0.30 m will form a solid barrier 0.61-1.22 m below the surface but leave untreated soil areas between the soil surface and the treated soil. Pylam D&C Green #8 (0.5% AI) was easier to detect in the SL ($>$83 $\mu$g/g: 90% probability) than in the SCL ($>$143 $\mu$g/g: 90% probability). Dye and insecticide distribution patterns in the soils were similar. In the SL, dye and insecticide were distributed similarly in $>$70% of the samples. However, 21-24% had dye but not insecticide. In the SCL, dye and insecticide were distributed similarly in $>$55% of the samples. Insecticide without dye was detected in 27-41% of the samples. Visual presence of dye may be used as a conservative estimator of insecticide distribution in the SCL, but may over estimate insecticide distribution in SL soils.
Subject Area
Entomology|Soil sciences
Recommended Citation
Davis, Robert W, "Effect of rodding tips and soil types on distribution of selected insecticides and a water soluble dye when applied for subterranean termite control" (1996). ETD collection for University of Nebraska-Lincoln. AAI9623620.
https://digitalcommons.unl.edu/dissertations/AAI9623620