Glyphosate in the control of kikuyugrass, and its effects on associated native and nonnative plants in Hawaiian National Parks

Abstract

Kikuyugrass (Pennisetum clandestinum) is an important range and pasture fodder grass in Hawaii, but is also a troublesome weed invading Hawaiian National Park Service areas. Kikuyugrass growth is significantly reduced by 0.05% Roundup (0.0205% glyphosate). This grass is eradicated (except for escapes shielded from spray contact in the matted grass) by 0.5% or greater concentrations. Sensitivities of other nonnative and of native plants associated with kikuyugrass varied according to the species, extent of coverage plant size, and herbicide concentration. Selectivity against kikuyugrass while preserving most associated native species was generally possible with 0.5 to 1% Roundup, especially if care is taken in application to avoid undue exposure to native plants. Control of kikuyugrass with glyphosate in natural areas is therefore a feasible and practical management approach.