The toxicity to bluegill sunfish, Lepomis macrochirus, Rafinesque, of granular formulations of ten commercial herbicides is presented. The following chemicals are included: three esters of 2,4-dichlorophenoxyacetic acid; potassium salt of 2- (2,4,5-trichlorophenoxy) propionic acid; disodium salt of 3,6-endoxohexahydrophthalic acid; a mixture of the latter two materials; 2,3,6-trichlorophenylacetic acid; 2-methoxy-3,6-dichlorobenzoic acid; isopropyl n- (3-chlorophenyl) carbamate; and 2,6-dichlorobenzonitrile. The difference in the median tolerance limit of bluegill sunfish to liquid and granular formulations is discussed. Of the ten herbicides tested, most proved less toxic as granular formulations than as liquid formulations. The difference in toxicity as affected by granule size and type is also discussed.
