The effects of the imidazolinone herbicide AC 263,222 on crops that may be rotated with soybean were studied in the greenhouse and field. Corn, grain sorghum, cotton, rice, wheat, soybean, and Italian ryegrass were planted directly into treated soil after AC 263,222 was incorporated. In the field, AC 263,222 at rates as high as 35 g ai ha–1 did not reduce shoot weight or emergence of these species. Some visual injury occurred, but was 20% or less 28 d after planting for all crops. Crops were more sensitive in the greenhouse, where reductions in both shoot and root dry weight were observed. AC 263,222 at 13, 13, and 7 g ha–1 reduced corn, grain sorghum, and Italian ryegrass shoot weights, respectively. Cotton, rice, and wheat tolerated rates from 27 to 55 g ha–1. Biomass reduction occurred with all crops at 55 g ha–1 and above. Because AC 263,222 will be registered for use in soybean at 9 to 18 g ha–1, and potential rotational crops were planted immediately after soil treatment, problems with injury to these crops are not expected.
