About Dothistroma needle blight (DNB)
DNB lives only on pine needles. DNB is caused by two distinct fungal species:
- Dothistroma septosporum – introduced to New Zealand
- Dothistroma pini – not present in New Zealand
Infection of both fungal species can occur together. Dothistroma septosporum and Dothistroma pini are both regulated in New Zealand.
Why this is a problem for New Zealand
DNB infects needles of all ages, killing pine needles and reducing the growth of the tree. Serious infections can kill a pine tree. The wood of the tree becomes denser, making it harder to process.
New Zealand has a highly suitable climate for the establishment of DNB.
The disease could cost the forestry industry millions of dollars each year in crop losses and disease control.
How DNB could get here
People bringing or sending plant material infected with DNB is the most likely way DNB could get into New Zealand. The fungus could also get here on pine nursery stock or pine needles.
Biosecurity New Zealand has strict measures in place to reduce the chance of pine diseases like DNB getting through the border.
How to identify DNB
Image: CC 2.0 US Department of Agriculture
- DNB is also called red band needle blight because of the red coloration of the bands on the needles.
- Needles remain rigid and are not easily removed from branches, even after they have died.
- Eventually, tiny dark brown or black fruiting bodies are produced and release spores.
- Symptoms are usually first seen at the base of the tree's crown.
- Symptoms start on the new flush of needles around December or January, with peak disease symptoms occurring around September.
- Disease development continues through to winter.
- Pinus radiata up to 15 years of age is most susceptible to DNB.
- The symptoms of Dothistroma septosporum and Dothistroma pini are the same.
Global distribution of Dothistroma needle blight
Global geographic distribution and host range of Dothistroma species.
Tell us if you find it
If you're a forester and you find similar symptoms:
- photograph it
- don't touch it as you could spread the fungus
- call 0800 80 99 66
- ensure you follow good biosecurity procedures to prevent the spread of disease.
Note: This information is a summary of this disease's global distribution and potential impacts on New Zealand.
