Phenology and Control of Common Broomweed on Texas Rangelands

Abstract

Common broomweed (Gutierrezia dracunculoides (DC.) Blake) were effectively controlled with 2,4-D at 0.125, 0.25 or 0.5 lb./acre applied during stem elongation around May 15. The same rates of 2,4-D were less effective when applied in early April prior to complete emergence of the common broomweed seedlings or in mid-June after initiation of floral branches. Picloram combined with 2,4-D at 0.063, 0.125 or 0.25 lb./acre of each herbicide controlled 94 to 100% of the common broomweed population regardless of application date. Dicamba was more effective when applied in early spring than were equal rates of 2,4-D. Control of common broomweed from applications of picloram or dicamba in early April was attributed to residual herbicide activity on seedlings germinated subsequent to treatment. However, no treatment prevented germination and establishment of common broomweed in the fall following application of herbicides in the spring.