Research associate Richard Townsend said the project has seen a reduction of pesticide costs as a proportion of milksolid revenues from 23% to 7% a year.
The project has been cost-effective with a return on investment of $10 for every dollar spent over three years.
“The manuka beetle has a sporadic history as a pasture pest, being recorded occasionally damaging pastures on newly developed, marginal land. Insecticides are hard to use effectively and they do not appear to keep up with its relatively high reproductive rate,” Townsend said.
“In this particular region, the flipping of soil to improve pastures has exposed sandy soil, which appears to be a perfect habitat for manuka beetle larvae.
“Most of the success in this project came from farm mapping. Farmers were encouraged to identify paddocks and areas within paddocks to identify damage-prone soil types. This enabled farmers to better target their insecticide applications and reduce usage by a considerable amount.”
Townsend said studies of the biology and lifecycle of the two species found that it would be economically impractical to try to control the adult beetles or eggs and that the larvae life-stages were susceptible to insecticides.
“We’re now also looking at integrated pest management strategies, such as modifying pasture establishment practices or planting tall fescue or chicory pastures that will hopefully reduce the impact of the beetle.”