STUDIES ON BROMADIOLONE AGAINST THE PIKA AND THE ZOKOR

The work was carried out on the alpine meadow of Menyuan county , Qinghai (an elevation of 3200 m) between September 1984 and September 1985. This paper deals with a series of; experiments in which we used Bro-madiolone ( Maki ) to kill plateau pika ( Ochotona curzoniae) and plateau zokor (Myospalax baileyi) . Quantitative determinations were made for the acute oral toxicity of Bromadiolone (LD_(50)) to plateau pika and plateau zokor, which are 0.430?.215mg/kg (95% confidence limit) and 1,310 + 0.710mg/kg (95% confidence limit) respectively. Regression equations of lethal dose individualy are Y = 0.2813X+ 5.1030 and, Y = 3.500X +4.589 respectively. The results show that Bromadiolone can be a single-dose rodenticide. In the experiments most of rodents poisoned were killed within 4-6 days, ranging from 2-9 days. The LD_(50) of the cock and the stone marten (Martes foina) is nine times more than the lab rat. In field trials against the zokor, pieces of carrots were used as baits mixed with Bromadiolone at a ratio of 0.02% (200ppm). As a result, the population reduction was 74.46%. And the efficiency for whole-wheat bait with 0.01% (lOOppm) of Bromadiolone against the pika was 100.0%. All these poisoning baits are of good acceptance. In short, it has been showed clearly that a potential to replace Warfarin and other first-generation anticoagulants which require repeated feedings to kill target animals. It has a good safety margin to most non-target species. It is suggested by the authors that the poison may have merit as an alternative rodenticide over Zinc phosphide and Fluoracetamide often used on grassland for rodent control.