Herbicides: Combination Enhances Selectivity

The herbicides N-(3-chloro-4-methyphenyl)-2-methylpentamamide (solan) and 1, 1'-dimethyl-4, 4'dipyridylium dichloride (paraquat) were less toxic to tomato plants when applied together than either one alone. However, the combination was more toxic to crabgrass and eggplant. This phenomenon may result from the interaction of the herbicides with photosynthesis.