Field experiments were conducted during 1981 to 1984 to evaluate paraquat for weed control in alfalfa established for less than one year. Treatments were applied in March to alfalfa up to 4 cm tall and/or after cuttings to alfalfa up to 10 cm tall. Weeds were up to 20 cm tall. Paraquat applied in March controlled common chickweed and shepherd's-purse in some experiments. It did not control birdsrape mustard when applied after cuttings. Paraquat suppressed growth of perennial broadleaf weeds and grasses and reduced pressure from annual grasses in some experiments. March treatments generally did not increase, but sometimes decreased alfalfa yields. Paraquat applied after cuttings did not affect alfalfa yields in the majority of the experiments.

Wettable powder and granular formulations of pronamide [3,5-dichloro(N-1,1-dimethyl-2-propynyl)benzamide], applied at 1.7 kg/ha to the soil surface or incorporated to depths of 1.3 to 7.5 cm, controlled dodder (Cuscuta indecora Choisy and C. campestris Yunck.) completely in the greenhouse for periods of 6 to 16 weeks. Seedlings emerged in pronamide-treated soil, but did not elongate normally and did not twine. Pronamide had very little activity as a vapor. In the field, the same rate applied to the soil surface and sprinkler irrigated or mechanically incorporated with the soil usually controlled dodder for about 1 month longer than did the standard herbicide, chlorpropham (isopropyl m-chlorocarbanilate) at 6.7 kg/ha. Pronamide at 6.7 kg/ha did not injure established alfalfa (Medicago sativa L.).

Chloramben effectively controlled weeds in lettuce and endive grown on muck soils better than thiobencarb and chlorpropham. Chloramben at 1.1 kg ai/ha controlled two weeds economically important on muck soils, livid amaranth and oakleaf goosefoot. Chloramben applied preemergence at 1.1 kg/ha and higher caused early stunting of lettuce which the lettuce outgrew by harvest. Field-seeded endive was stunted severely at these same rates, severely reducing yield. Transplants improved tolerance of all crops. Effective use rates on muck soils were 25% to 50% of those typically used on mineral soils.