Tolerance of cicer milkvetch (Astragalus cicer L.) seedlings to 2,4-DB [4-(2,4-dichlorophenoxy)butyric acid], 2,4-D [(2,4-dichlorophenoxy)acetic acid], and phenoxy-diclofop {2-[4-(2,4-dichlorophenoxy)-phenoxy] propanoic acid} mixtures was evaluated in greenhouse and field experiments. In the greenhouse, seedlings in the cotyledonary and primary-leaf stages of growth were more susceptible to 2,4-DB alone and to combinations of 2,4-DB plus diclofop than seedlings in the second- through the fifth-leaf stages. All rates of 2,4-D with or without diclofop (1.7 kg ae/ha rate) reduced seedling growth at all stages of development. In the field, 2,4-DB with or without diclofop did not reduce seedling growth. Seedling growth was suppressed by 2,4-D alone at rates of 1.02 and 1.36 kg ae/ha throughout the growing season. All combinations of 2,4-D plus diclofop suppressed seedling growth, but the suppression was particularly apparent at rates of 0.68 kg ae/ha or higher of 2,4-D.
