Effect of Flumetsulam Plus Clopyralid Soil Residues on Several Vegetable Crops and on Sweet Corn (Zea mays) Cultivars Grown in Rotation

Abstract

The effect of soil residues of flumetsulam plus clopyralid on several vegetable crops grown in rotation with field corn was investigated over 2 yr. The effect of soil residues of flumetsulam plus clopyralid on sweet corn cultivars of varying sensitivity to acetolactate synthase (ALS)-inhibiting herbicide was also investigated. Flumetsulam plus clopyralid was applied preemergence (PRE) to field corn at 0, 50 + 135, and 100 + 270 g ai/ha, respectively, in 1993 and 1994. Cucumber, tomato, cabbage, potato, pepper, pea, and sweet corn were planted each spring, both 1 and 2 yr following the herbicide application. Cabbage was very sensitive and showed visible injury symptoms and yield reductions both years following flumetsulam plus clopyralid application. Pepper showed a yield reduction only in 1995. All other crops showed no injury or yield reductions. Flumetsulam plus clopyralid was applied PRE and postemergence (POST) to six sweet corn cultivars in 1995. These six sweet corn cultivars were replanted into the same site 1 yr later. Flumetsulam plus clopyralid severely injured three of six sweet corn cultivars in 1995, the year of application. Soil residues 1 yr later, however, did not injure or reduce yield of any sweet corn cultivars, including cultivars sensitive to ALS-inhibiting herbicides.