SYNERGIE HERBICIDAL AGENT

1466634 Plant growth regulator AMERICAN CYANAMID CO 28 April 1975 [28 May 1974] 17633/75 Heading C1B [Also in Division A5] A synergistic herbicidal and plant growth regulating composition comprises a mixture of (a) a 1,2-dialkyl-3,5-diphenyl-IH pyrazolium salt of the formula wherein R 1 is methyl; R 2 is alkyl C 1 -C 4 ; X is an anion; Y, Y1, Z and Z1 are each hydrogen, halogen, methyl or methoxy; and m is an integer from 1-3; provided that only one phenyl ring can be substituted on the carbon parato the pyrazolium ring with a substituent other than hydrogen; and (b) a compound of the formula: R-N(CH 3 ) 3 Y where R is a lower aliphatic radical (C 1 -C 4 ) selected from haloalkyl, alkylene, haloalkylene, cyanoalkyl, mercaptoalkyl, alkoxyalkyl and epithioalkyl; and Y is non-phytotoxic anion, the cation of I and II compounds being present in a weight ratio of from 1 : 1 to 1 : 16 respectively. Suitable anions for compounds I and II include chloride, bromide, iodide, acetate, citrate, succinate, formate, sulphate, hydroxide, bisulphate, methyl sulphate, benzene sulphonate, C 1 -C 3 alkoxy benzene sulphonate and C 1 -C 3 alkyl benzene sulphonate. A particularly preferred composition comprises (a) 1,2-dimethyl-3,5-diphenyl-IH- pyrazolium chloride, bromide, methyl sulphate or bisulphate and (b) (2-chloroethyl)-trimethylammonium chloride, bromide, fluoride or iodide. Surfactants, spreaders and stickers may also be added. The composition can also be used for the concurrent control of relative stem growth of crops, e.g. wheat, barley and rye.