Red Needle Cast fight progresses
A TEN-YEAR BATTLE TO GET ON TOP OF the Red Needle Cast blight appears to be making significant progress, the 2017 Forest Growers Research conference was told in Christchurch last month.
Scion researchers, Nari Williams and Lindsay Bullman, told the conference their studies had tracked the original source of Red Needle Cast to Oregon, on the Pacific North West Coast, and it is believed to have arrived on either machinery or from tree material imported from the US.
The blight mostly hits pine trees in wetter, cooler months – and there was a particularly severe outbreak this year in the Wairarapa – turning needles red as they are affected and die, until they fall off.
It has become widespread throughout the North Island and has been discovered as far south as Otago since it was first detected in 2008, but the research by Dr Williams, Mr Bullman and their colleagues shows that the trees do recover the following season, with fresh growth seen after the dead needles die off. It still hampers the growth of the tree, however, and research is now focused on how to manage and possibly reduce its effects.
Red Needle Cast affects both of our major plantation species, Radiata Pine and Douglas-fir, and whilst spraying with copper can be effective in controlling it for up to six months, the use of chemicals does not sit well with FSC certification. So a programme is currently under way to see if trees can be bred that are resistant to, or less affected by the blight in future.
Dr Williams and Mr Bullman say Red Needle Cast is probably here to stay, but a combination of limited chemical use and breeding resistant pines could reduce its effects within a few years.
Fellow Scion scientist, Grant Pearse also demonstrated how the organisation is developing a suite of tools for detecting and monitoring Red Needle Cast and other diseases, from use of satellites to cover larger areas to drones for more locailised analysis. One aim is to come up with a system that automatically alerts forest managers and owners when diseases are detected.
NZL