Efficacy of a carbon monoxide gas cartridge against field rodents
Efficacy data of a gas cartridge are reported. The gas cartridge contains 50 g of potassium nitrate (27.5 g, 55%) mixed with sawdust (22.5 g, 45%). When ignited, it generates large amounts of carbon monoxide (avg. 23.46%) and carbon dioxide (avg. 26.26%). A mimic field trial was carried out on a winter day. The air temperature averaged 1.2°C, ranging from -3.3°C to +5°C. Sixteen adult albino rats were killed within 3 minutes exposure in a man-made burrow system, 200 cm long, with an inside diameter of 8 cm. Field trials were conducted in different parts of China, and there were no survivors in the 108 burrows treated. Upon excavation 144 dead rodents were recovered. The first test was carried out in Zhengding, Hebei Province. (The site was along a sunning ground where cereals are dried.) Each of 53 burrows was treated with a 50-g gas cartridge. When the burrow systems were excavated, 81 dead rodents were found: Cricetulus barabensis, 38 (46.9%); C. triton, 28 (34.6%); Mus musculus, 14 (17.3%); and Apodemus agrarius, 1 (1.2%). The second trial was carried out in a sugarcane field near a ditch in Zhangjiang, Guangdong Province. Fifty-five dead rodents were dug out of the 50 burrows treated: Rattus flavipectus, 26 (47.3%); Bandicota indica, 18 (32.7%); R. losea, 7 (12.7%); and Suncus murinus (Insectivore), 4 (7.3%). The third trial was conducted in a high mountain grassland pasture above 3500 m in Qinghae Province. Five marmot burrows were each treated with a dose of 600 g of gas cartridges per burrow. Eight dead Marmota hymalayana were found near the burrow entrance.