Pesticidal Activity of Methyl Isoxathion

• Published in: Fish Pathology Vol. 13; no. 2; pp. 109 - 113
• Main Authors: NAKAJIMA, Kenji, KITANO, Noritoshi
• Format: Journal Article
• Language: English
• Published: The Japanese Society of Fish Pathology 1978
• ISSN: 0388-788X; 1881-7335
• DOI: 10.3147/jsfp.13.109

Several kinds of insecticides have been applied in eel ponds in Japan to eliminate unfavorable zooplanktons for fish. Among these organisms, Ostracoda (Crustacea) is strongly resistant to the chemicals so far adopted. In the present study, methyl isoxathion, a new organo-phosphorous compound developed by Sankyo Co., was confirmed to be highly effective against the Ostracoda, Candonocypris assimilis SARS, 1895 and Heterocypris incongruens (RAMDOHR, 1808) subsp. attenuata (GAUTHIER, 1938), when applied in the water. A 50% emulsion of the compound killed the pests in clean water at levels of 0.1 to 0.2 ppm during 3 days at room temperature, but the effectiveness of the chemical was found to reduce at a low temperature and by the concomitance of phytoplankton and/ or the mud. The drug was not harmful to the young fishes of Anguilla anguilla, A. japonica, Carassius auratus and Cyprinus carpio, at concentrations below 2.5 ppm of the emulsion.