A dairy industry advisor says plant scientists are still searching for a grass that will give farmers the best combination of pest protection and pasture durability.
Dairy NZ surveys have shown that pasture persistence, or the lack of it, has become a concern for dairy farmers.
The issue is one researchers, seed companies, farmers and contractors are tackling in an industry body called the Pasture Renewal Leadership Group.
Dairy NZ productivity team leader Rob Brazendale, who chairs the group, says the pasture persistence issue became more prominent following the 2007 drought in Waikato, where pastures suffered severe damage from black beetle.
That has been linked to a fungal endophyte in new lines of ryegrass.