BIOLOGY AND CONTROL OF PYPGRASS

Pypgrass (Ehrharta villosa) is an invasive rhizomatous grass weed which is smothering the native dune flora at Turakina Beach, near Wanganui. A deep rhizome system, sunken stomata, in-rolled leaves and a mycorrhizal association contribute to the aggressive nature of this weed in the dune community. A field trial showed that haloxyfop will successfully control pypgrass; successive applications give best results. Several other monocotyledons from the dune community were shown in a pot trial to be unaffected by haloxyfop. Studies of pypgrass biology suggest that, although vegetative spread is aggressive, establishment from seedlings is poor. Eradication should be an achievable goal.