STUDIES ON THE BIONOMICS AND CONTROL OF THE BURSATE NEMATODES OF HORSES AND SHEEP: VI. ON THE LETHAL EFFECTS OF SOME NITROGENOUS CHEMICALS ON THE FREE-LIVING STAGES OF SCLEROSTOMES

Abstract

The effect of ten chemicals, containing a nitrogen radicle, on the free-living stages of Sclerostomes is discussed. Chloropicrin is the most lethal chemical yet tested; under the conditions of these tests, one part of chloropicrin will sterilize approximately 2,300 times its weight of fresh faeces, but its disadvantages weigh against its practicability for farm use. Aniline will sterilize about 525 times its weight of fresh faeces when undiluted and 800 or 900 times its weight as a very weak solution. Calcium cyanide, whose value is also limited by its danger, will sterilize 530 times its weight of fresh faeces. Pyridine is slightly more effective when applied undiluted or as a strong or medium strength solution; it will then sterilize about 400 times its weight of fresh faeces. Ammonium carbonate will sterilize approximately 50 times its weight of fresh faeces. Ammonium chloride, cupric nitrate, and ammonium nitrate will sterilize approximately 30, 25, and 21 times their own weight of fresh faeces respectively. They are, however, more effective if applied as medium strength solutions, and cupric nitrate in lesser amounts causes the death of many larvae after they have reached the third stage, although the chemical was added to the fresh faeces. Ammonium sulphide, as a 15% solution, will sterilize nearly 14 times its weight of fresh faeces. Saponin probably has no lethal value against Sclerostomes chemically, although physically it may affect them.