Cyclaneusma needle cast
Symptoms, identifying factors, spread and treatment for Cyclaneusma needle cast (CNC).
Symptoms
Needles:
- turn mottled yellow then brown
- often develop transverse (horizontal) bands during the later stages of disease development
- remain rigid and are very easily removed from branches.
After the needles are cast, the tree crown appears very thin.
Other identifying factors
- The entire tree crown may be affected.
- Disease is not uniform in a stand unless the trees are genetically identical – affected trees are scattered amongst unaffected trees.
- Symptoms start September or October, with a second (usually less severe) cast occurring around April.
- Trees aged between 6 and 20 years are most affected.
Spread
CNC is abundant in the Waikato and Taranaki regions and very common in Northland and on the east coasts of both the North and South islands.
It is uncommon in Otago and the greater Wellington-Wairarapa region.
No areas in New Zealand are known to be free of CNC.
Treatment
No treatment is believed to be economically viable.
Farm Forestry New Zealand has more information on the diagnostic features, including pictures, and disease location.