Wednesday, July 6, 2022

Bristle grass spreads causes concern

There is 10 times the amount of yellow bristle grass (YBG) in the Waikato compared with when it was first noticed, according to AgResearch weed specialist Trevor James.

The invading summer growing grass can significantly damage pasture quality and ultimately reduce milk production.

“We have also found it in the South Auckland region now and it’s moving down through Taranaki at a huge rate of knots,” James told a recent field day at Patarangi.

It has also spread to three areas of the South Island, with Canterbury being a prime environment.

YBG thrives on warm temperatures and will typically germinate at 20-35 degC during November and December, flowering in February. It continues to reduce the pasture quality in late summer and autumn and once it dies off leaves open pastures which mean further re-infestation as well as an opportunity for other weeds to establish.

James said it’s the first grass weed of significance in pasture but there is a new spray on the market for management and control.

Bayer’s Puma S should have a 90-95% strike rate if applied at the right time, which is after germination but before YBG seeds.  

For further information visit to see a copy of The Ute Guide on Yellow Bristle Grass.

More articles on this topic