Phytotoxicity of bispyribac sodium and other herbicides to rice

In studies on phytotoxicity of bispyribac sodium and 5 other herbicides to rice by pot tests in greenhouse, plant injury symptoms were described, poisoning process of rice by herbicides observed, and factors on the phytotoxicity assessed. Bispyribac sodium is more heavily phytotoxic to japonica rice than to indica rice and hybrid rice, and 1-3 leaf stage rice seedling is more vulnerable by bispyribac sodium and mefenacet than 4 leaf stage rice seedling. The higher dosage of bispyribac sodium, mefenacet and fenoxaprop p ethyl, the more serious the damage. Rice planted in different soil shows different degrees of pytotoxicity by bispyribac sodium, and it causes less toxicity to rice if there is a thin layer of water above soil during spraying, while the phytotoxicity occurs heavily at high temperature. The phytotoxicity of bispyribac sodium may be reduced by a safener.