Pine needle diseases
There are 4 main pine needle diseases in New Zealand. Find out what the diseases are and how to recognise and treat them.
Blight in Radiata pine
Blight is a type of plant disease commonly caused by fungi. There are different sorts of fungi that can cause blight, including mildews, rusts and smuts.
If your pine trees look like they may be suffering from blight, check the table to narrow down the likely cause.
| | Cyclaneusma needle cast | Physiological needle blight | Red needle cast | Dothistroma needle blight |
|---|---|---|---|---|
| When | September to November | June to November | April to October | All year |
| Tree age | 6 to 20 years | 15 years + | Usually 3 years + | Planting to 15 years |
| Spread | No pattern Very severe |
Small area affected More than 50% of trees within the affected area |
Small to medium-sized area affected Almost all trees within affected area |
Widespread Almost all trees within affected area Wide variation between trees |
| Needles | Yellow Gold Brown |
Brown Red-brown Grey Olive (with or without black bands) |
Yellow Red Olive (with or without black bands) |
Brown Grey Red bands with black spots |
| Wilt | None | Only at later stages | None | Slight |
| Retention | Needles detach easily | Needles are retained | Needles detach easily | Needles are retained but die |
| Cambium & bark | No damage No lesions No resin |
No damage No lesions No resin |
No damage No lesions Some resin blobs may appear at base of affected trees |
No damage No lesions No resin |
Very severe
More than 50% of trees within the affected area
Almost all trees within affected area
Almost all trees within affected area
Wide variation between trees
Gold
Brown
Red-brown
Grey
Olive (with or without black bands)
Red
Olive (with or without black bands)
Grey
Red bands with black spots
No lesions
No resin
No lesions
No resin
No lesions
Some resin blobs may appear at base of affected trees
No lesions
No resin
Detailed disease descriptions
The 4 main diseases differ from each other in a number of small but important ways. See our pages for more information on their identifying factors, spread and treatment.
If you're unsure what may be affecting your forest, Farm Forestry New Zealand has a step-by-step identification guide that may help.
Scion's field guide has more information including identification, how to estimate the amount of current infection in a tree crown and the number of trees that should be assessed in a stand during inspections.