Yellow bristle grass: a recent weed incursion in Waikato dairy pastures

Abstract

Yellow bristle grass (Setaria pumila) is a summer growing annual grass with a C4 photosynthetic pathway. It is now becoming a serious weed in pasture where it is highly competitive with perennial ryegrass (Lolium perenne)/white clover (Trifolium repens) and is avoided by stock when at the seed head stage. On severely infested farms, it is estimated to cause production losses in the order of $100 000/100 ha unit, mostly due to stock not grazing areas where the yellow bristle grass is seeding. Keywords: yellow bristle grass, Setaria pumila, pasture, grass weed