Dothistroma Needle Blight

Dothistroma Needle Blight (DNB) is a disease that can be caused by the two fungal pathogens, Dothistroma septosporum and Dothistroma pini. The disease has been present in Great Britain since the 1950s and is now a very significant disease of pine species there. The disease was found in Northern Ireland in 2011 on Corsican pine. The disease is present in most other EU Member States and in many other countries outside the EU.

Pine tree species are the primary host of DNB.  In Britain, Corsican pine has been the most severely affected pine species but severe damage to lodgepole pine has also been reported. To date Scots pine has been less severely affected in Britain. There are other less susceptible conifer hosts.

In September 2016, DNB was found in Ireland for the first time. It was identified as being present on Scots pine trees at two privately owned (grant aided) forests, one in southwest Limerick and one in northwest Cork. Samples taken from Scots pine trees at the two forests in early August were analysed and laboratory results confirmed the presence of D. septosporum in early September. 

Symptoms

Dothistroma Needle Blight was previously referred to as red band needle blight because of the red and colourful bands displayed across the infected needles.

Trees with severe DNB infection will appear with mostly just the current years foliage intact. Due to the loss of the previous season’s needles, a 'bottle brush' appearance to the trees can result. The lower branches closer to the ground are often more affected. 

Further information

• Forest owners should be vigilant for unusual ill-health in trees and report any concerns to forestprotection@agriculture.gov.ie or by using www.treecheck.net.