Strychnine Residue Studies and Their Implications in Rodent Control

Applications of 0.29, 1.0, 2.63, and 5.26% strychnine-impregnated grain baits were applied below ground to 10' x 10' plots of alfalfa to determine translocation of strychnine from the soil to plants. Four replicates of each concentration were made and the alfalfa analyzed for strychnine residues. Four 10' x 10' plots were utilized as controls. Plant samples were taken on Day 1, Day 9, and Day 14. Strychnine was not detected in any of the samples above the limit of detectability (0.02ppm). Apples from trees subjected to a normal, 1 x normal, and a 3 x normal gopher control strychnine bait application were sampled and analyzed for residues. Four replicates were used and samples were taken on Day 4, Day 14, and Day 28. Analytical methods were identical to those utilized for alfalfa with normal to 3 x normal application rates of strychnine baits. There was no detectable strychnine translocated from the soil to the fruit of the apple trees. When using an authorized application rate of strychnine-impregnated bait utilized in a gopher control program, there is apparently no translocation of strychnine from the soil to the harvestable crops involved in this study. Because of the strong sorption characteristics of strychnine, even on soils of low cation exchange capacity (6.8 meq/lOOg), mobility in soils was found to be minimal.