THE ECOLOGY AND CONTROL OF PERENNIAL PEPPERWEED (LEPIDIUM-LATIFOLIUM L.)

Field experiments were conducted for the control of perennial pepperwe ed with tillage and herbicides. Perennial pepperweed infests a wide ra nge of soils and plant communities. These studies were conducted in na tive hay meadows, with wild-flooding irrigation and saline/alkaline so ils. Such meadows are typical of livestock ranches throughout the Inte rmountain Area. Tillage with periodic disking over a 2-yr period resul ted in no permanent reduction in perennial pepperweed cover. Applicati ons of 2,4-D or glyphosate eliminated perennial pepperweed seed produc tion and greatly reduced top growth but had no permanent influence on cover of the weed by che second season following application. Applicat ions of chlorsulfuron in the spring at flowering, in late summer after hay harvesting, or in the autumn, were effective in suppressing peren nial pepperweed for 2 yr or more following application.