The Clutha Agricultural Development Board has begun work with AgResearch scientist Colin Ferguson on demonstrating to farmers the most up-to-date technologies to manage grass grubs on pastoral land in its latest Sustainable Farming Fund project.

Grass-grub is an intractable native pasture pest that causes significant production losses for sheep and beef and dairy farmers throughout the country.  A moderate grass-grub infestation (300/m²) will cause a 20% production loss. At higher levels, pasture grasses are destroyed, allowing inferior or non-palatable plants to invade which permanently reduces  pasture production and quality, and leads to costly pasture renovation.

Six farmers from across the Clutha district (Te Houka, Owaka, Hillend, West Otago, Clydevale and Hindon) have volunteered demonstration plots on their farms. They are out looking for last season’s grass grub damage of their pastures and making notes to inform this coming season’s management methods.

“Farmers know it’s no good waiting till the grub damage appears to get the best management in place, but they struggle to investigate and prepare at the appropriate times,” said Malcolm Deverson, Projects Manager for the Ag. Board. “ The annual management process, which involves an understanding of the grass grub life cycle, is what Colin is going to help farmers with.”

There is have been indications that the organophosphate insecticides that are often used to spray the grubs may not be available to farmers in the future.  AgResearch is keen to explain to farmers the new technologies that they have been developing which do not involve harmful chemicals and which avoid costly regrassing.  The project is also supported by Beef + Lamb New Zealand through the FITT fund.

“We are keen to show farmers these new ideas, so there will be short ‘neighbourhood-type’ meetings at two or three of the demonstration farms in November. We hope people can come along and work out how they can save time and money and avoid the nuisance value of these pests.”