Toxicity of Chromolaena odorata (L) R.M. King & H. Rob to Hybrid Catfish Fingerlings

Abstract

Allelopathy plant such as Siam weed (Chromolaena odorata) could inhibit germination of other weed growth. However, integrated farming which rice propagation and fish culturing are combined; the use of Siam weed for weed control in rice paddy field should be considered for its toxicity to fish. This experiment aimed to determine acute toxicity of Siam weed crude extract on hybrid catfish fingerlings (Lctalurus punctatus × Lctalurus furcatus). Siam weed leaves were dried and ground before adding to ethanol in a ratio of 1:10. The liquid part was filtered and diluted in round glass aquaria at 0, 40, 400, 800, 1200 and 1500 ppm. Hybrid catfish fingerlings of 10 gram/fish were stocked into the aquaria not more than 1 fish/L and maintained in this condition for 96 hours. It was found that at the maximum concentration 1500 ppm, 100% mortality was observed within 3 hours. While the fish continued to die and stop dying at 24 hours at 1200 ppm. The acute toxicity of Siam weed crude extract LC₅₀ (96 hours) of this experiment was 1,111.09 ppm. This suggested that Siam weed, if using in high concentration, would be toxic to fish.