Studies on the toxicity of tartar emetic to the Mexican fruit fly and the effects of applications of tartar emetic on citrus tree
Plummer, Charles Carlton
Ohio State Univ Abst Of Doctor S Dissert 35: 117-122
Various factors affecting toxicity tests in the laboratory were controlled. A detailed description is given of the standardized exptl. procedures adopted. They involve observations on the mortality of flies at equal logarithmic intervals, conversion of % mortality to probits, and analysis of variance of data recorded from 16 or more cages mcluded in each expt. Flies lived longer in expts. started at 6 P. M. than in those started at 6 A. M., 12 M., and 2 P. M. The av. mean length of life of flies tended to be less as the size of the cage was reduced. When flies were starved for 24 hrs. and this was followed by access to food for 3, 6, and 12 hrs., respectively, previous to the start of an expt. it was found that flies having access to food for 3 hrs. succumbed most rapidly while those that were exposed to food for 12 hrs. lived the longest. No significant difference was shown between the mean length of life of flies exposed to concs. of tartar emetic ranging from 1 to 6 lbs. in 100 gal. of aq. soln. containing 20 lbs. of granulated sugar. In another expt. differences between 6 lbs. and 1 and 5 lbs., respectively, were highly significant. A 3d expt., however, showed no significant differences between 8 lbs. of tartar emetic and 1, 2, 4, and 6 lbs., respectively. Differences between 8 lbs. and 0.125, 0.25, and 0.5 lb., respectively, were highly significant. In a 4th expt. differences between 0.75 lb. and 0.25 and 0.125 lb., respectively, were highly significant. Tartar emetic at a conc. of 4 lbs. in 100 gal. of aq. soln. containing 20 lbs. of granulated sugar was, as determined by [chi]2, no more toxic to one sex than to the other. No damage to citrus foliage was noted when sprays prepared with tartar emetic were applied as a mist. Detn. of soluble solids and citric acid in the juice of citrus fruit showed that the composition of the fruit was not injured. Fruit tested included Marsh seedless grapefruit picked from trees that had received 44 applications of tartar emetic sprays during 2 seasons and Valencia oranges from trees that had received 41 applications during the course of 3 consecutive seasons.