In Britain, Dothistroma Needle Blight (DNB), also known as Red Band Needle Blight, is caused by the fungus Dothistroma septosporum. It has been found on a range of conifer species, but pine (Pinus) are by far the most common hosts, with Corsican pine, lodgepole pine and Scots pine all now affected.
Infected needles typically develop yellow and tan spots and bands, which soon turn red. The ends of the needles then turn reddish-brown whilst the needle base remains green. Needle symptoms are most apparent in June and July when the spore-containing fruit bodies are most abundant, after which the infected needles are lost and trees can have a typical ‘lion's tail’ appearance, with only a tuft of the current year's needles remaining at the branch ends. This defoliation can continue year on year and gradually weaken the tree, significantly reducing timber yields. It can also eventually lead to mortality. Experience in New Zealand and on Corsican pine in England suggests that the percentage of crown infection equates to the percentage yield reduction.
The disease has been found in all of the Commission's Forest Districts in England and Scotland, and three out of four Forest Districts in Wales. In 2006, 70 per cent of the Corsican stands inspected in Britain had the disease, and it is estimated that 44 per cent of these infected stands had crown infection levels greater than 30 per cent. Lodgepole pine is now also being severely affected in north and east Scotland. Although Scots pine has generally been considered to be of low susceptibility, an increase in the distribution and severity of the disease on this species is now being seen, particularly in Scotland. It is not yet known whether this will lead to mortality or extend significantly into the Caledonian pinewoods. The other main conifers used in British forestry continue to appear to have low susceptibility.
In 2010, the disease was found infecting pine plants in three forestry nurseries in Scotland. Further information about that is available in this position statement. In 2011 the extent of nursery findings has increased with this being the first time that both of the Forestry Commission's Delamere and Newton nurseries have been found to be infected in the same year.
Within the European Union the movement of pine plants intended for planting is regulated though plant passport arrangements. Our plant health authorities inspect growers of pine each year, and only grant authorisation to issue plant passports if a place of production and its immediate vicinity is free from DNB.
Management of Dothistroma Needle Blight is overseen by a Programme Board, (see Terms of Reference) set up in 2009. The Forestry Commission’s research programme includes: disease surveillance; monitoring of the disease’s extent, severity and impact; increasing our understanding of the fungal biology and disease epidemiology; and investigations into potential management strategies. (Updated 26 September 2011)
Forestry Commission Scotland (FCS) has established a forest tree nursery transition scheme which provides support for infected forest tree nurseries in Scotland, conditional on their setting out and implementing a Dothistroma needle blight resilience action plan for their nursery. Read details of the scheme. (Updated 2 February 2011)
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