The Compatibility of Rhodamine B Dye with Herbicides for Common Crupina (Crupina vulgaris) Control

The compatibility of rhodamine B dye {N-[9-(2-carboxyphenyl)-6-(diethylamino)-3H-xanthen-3-ylidene]-N-ethyl ethanaminium chloride} with picloram (4-amino-3,5,6-trichloro-2-pyridinecarboxylic acid) or dicamba (3,6-dichloro-2-methoxybenzoic acid) was evaluated in the laboratory and field. Rhodamine B dye formulation (with or without a surfactant) did not affect dry weight of residue precipitated when mixed with dicamba. Formulated dye precipitated 11% more residue than nonformulated dye when mixed with picloram. Common crupina (Crupina vulgaris Cass. # CJNVU) field plant density was higher after applying a picloram spray solution with nonformulated rhodamine B dye compared to picloram alone. Common crupina density and biomass were higher after application with nonformulated dye and dicamba compared to dicamba alone.