Herbicidal Suppression of Bracken and Effects on Forage Production

Abstract

Nineteen herbicides in various formulations were tested preemergence and postemergence for control of western bracken (Pteridium aquilinum(L.) Kuhn var.pubescensUnderw.). Excellent suppression was obtained for 1 year with fall applications of granular formulations of 2,6-dichlorobenzonitrile (dichlobenil) at 6.7 and 10.1 kg/ha, 4-amino-3,5,6-trichloropicolinic acid (picloram) at 2.2 kg/ha, and 3,6-dichloro-o-anisic acid (dicamba) at 4.5 to 9.0 kg/ha. Bracken recovered rapidly after 1 year of suppression by dichlobenil, but other herbaceous species were killed. Bracken recovered considerably the second growing season after application of picloram or dicamba, although morphological effects were noticeable for 2 to 3 years, particularly from dicamba. No visual injury to grasses was apparent from picloram. Some injury to orchardgrass (Dactylis glomerataL.) was noted from dicamba.