Abstract
Laboratory tests were carried out on several single dose and anticoagulant rodenticides as a tracking powder against white mice and rats. In order to examine an attachability of the powder to a body surface, five 100 mesh powders, such as rice powder, starch, soybean powder, talc and silica gel were tested. Among them, rice powder attached to mice best, following starch, soybean powder and talc. The average powder weight attached was 0.5-0.7g per mouse in 15 second exposure. The tendency of effectiveness among the different powders containing 0.05% scilliroside which was contacted to the mouse coincided fairly with the order of attachability to the body mentioned above. In the test to examine the effect of rodenticides in the rice powder, the chemicals which gave the complete mortality in a time as short as 15-60 second were 0.05% scillirocide and 5% ANTU. The other chemicals also showed comparatively high mortality with the exception of 1% thallium sulphate. When powders containing single dose rodenticide were treated on a short runway which was made of tin plate, the mortality of rats was lower than that of mice exposed to the same powder. On the other hand, coumatetraryl, an anticoagulant rodenticide, showed 100% mortality in 3 to 7 days when 2g of 0.25% powder was treated on the runway in the area of 15×15cm.
