Weed management experiments with kidney beans were conducted at one irrigated site in 1991 and at two irrigated sites near Staples, MN during 1992. Green foxtail was the most difficult weed to control at the three research sites which agrees with survey results from dry bean growers regarding their worst weed problems. Hairy nightshade increased rapidly when weed management methods were reduced. Dry bean seed yields were highest in cultivated check plots on the farmer's field and in conventional practices plots at the Irrigation Research Center. Net economic returns, averaged over 1991 and 1992, for producing kidney beans at the Irrigation Research Center were $899/ha using conventional practices, $791/ha with cover crop practices, $734/ha with cultivated checks, $690/ha with herbicides only, and $208/ha on weedy checks. Kidney beans are an economical crop for North Central growers, but adequate weed management technologies are necessary for profitable production.

Various chemical and mechanical weed control treatments for kidney bean production were evaluated on irrigated, sandy loam sites from 1993 to 1995 near Staples, MN. Weed biomass can be controlled either mechanically or chemically, but a combination of the two gave the most effective and dependable weed control over years. Good weed control by either mechanical or chemical means reduced white mold infection of dry bean because of better aeration of dry bean plants and thus less favorable conditions for infection. Dry bean seed yields were inversely related to weed yields, and weed competition was similar from indigenous stands of either grass or broadleaf weeds. Row cultivation was more effective than rotary hoeing for controlling weeds, reducing white mold infection of dry bean, and increasing dry bean seed yields.