Red needle cast

Symptoms

Needle colouring:

• In initial stages, needles have distinct olive or olive-with-black resinous bands.
• In later stages, needles turn yellow then red-brown.

Needles remain rigid but are easily removed from branches.

Other identifying factors

• The entire tree crown may be affected.
• Symptoms may start anytime between March and September but are rare during summer.
• Peak disease occurs from July to September, depending on the region.
• Needles are cast or blown off the branch within a few months of symptoms. After the needles are cast, the tree crown appears very thin.
• Affects trees of all ages.

Spread

Red needle cast is abundant in parts of the Waikato, Central Plateau and Gisborne regions and is very common in Northland, the upper South Island and the Bay of Plenty.

It is uncommon in the greater Auckland region, Taranaki, the greater Wellington-Wairarapa region, Hawke's Bay and the area surrounding Abel Tasman National Park.

Treatment

Research by Scion shows copper fungicides may be effective in treating RNC. These fungicides are also used to control Dothistroma needle blight (DNB). The research is based on applying copper fungicide at the DNB rate.

Research is underway to find out the best timing and efficacy of copper against severe disease. Aligned research is also underway to find ways to forecast and measure how much disease affects tree growth. This will help with analysing the costs and benefits of disease control operations.

The Dothistroma Control Committee can help with options to treat DNB or RNC.