Red Nee­dle Cast fight pro­gresses

New Zealand Logger - - Forest Growers Research -

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

Red Nee­dle Cast can af­fect both Ra­di­ata Pine and Dou­glas-fir, but sci­ence is work­ing on re­duc­ing its ef­fects.

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