DARD combats Japanese Larch tree disease
August 2010
DARD COMBATS JAPANESE LARCH TREE DISEASE
A plant disease caused by a fungus-like pathogen known as Phytophthora ramorum (P.ramorum), has been diagnosed on Japanese larch for the first time in Northern Ireland.
DARD Forest Service Chief Executive, David Small, has confirmed three outbreaks of the disease in woodlands on the Antrim plateau. Around 200 hectares of public forest estate and a further four hectares of private woodland are affected.
The pathogen P. ramorum has potential to attack a wide range of woody plants and could cause significant damage to woodland and other habitat. It can be spread on footwear, vehicle wheels, tools and machinery, by the movement of infected plants and in rain, mists and air currents. The disease has also been recently confirmed in Japanese larch woodland in England, Wales and the south of Ireland.
Forest Service Chief Executive David Small explained: “This is the first time the disease has been confirmed on Japanese larch in Northern Ireland. It is important that DARD does everything it can to minimise the risk of the disease becoming established in our woodlands as it has the potential to cause significant damage to larch trees and the wider environment.
“The Department has taken appropriate steps to contain these outbreaks and based on scientific advice, infected Japanese larch on both public and private land will be felled. This is the best method for controlling this disease and preventing further damage. Bio-security precautions will also be put in place to prevent the further spread of the disease. Forest visitors are asked to observe any signage indicating the action they can take to help prevent spread of the disease, such as keeping to forest roads, keeping dogs on leads and removing soil and mud from shoes and boots before leaving the woodland.
Mr Small added: “I would urge all woodland owners and managers to remain vigilant for symptoms of the disease in Japanese larch and report suspicious symptoms to Forest Service.”
The first indication of the disease on Japanese larch trees, is a visible wilting of young shoots and foliage, or later in the growing season, withered shoot tips with yellowing needles which then become blackened. The infected shoots shed their needles prematurely. Trees may also have bleeding cankers on their upper trunks.
Forest Service can be contacted on telephone number 028 90524480.
Notes for Editors
- P. ramorum has a potential to attack a wide range of woody plants and could cause significant damage to woodland and other habitat if it were to become established. It poses a threat to certain tree species and other ecologically important plants. It is a non-indigenous pathogen in the UK and Ireland. Between 2002-2009 the diseases was found at 34 sites in N. Ireland, mostly on Rhododendron and other ornamental species at sites which included plant production/retail premises, private gardens, private estates and public parks. All these findings and outbreaks were successfully controlled, and on one site, containment and eradication of the disease is ongoing.
- The disease was first discovered to have infected Japanese larch in autumn 2009 by Forestry Commission in GB. Subsequently Forestry Commission has identified 55 confirmed infections and 237 suspicious sites across England and Wales. Recently Forest Service in the Republic of Ireland has reported one confirmed site and another site under suspicion.
- Suspected infections should be reported to: Forest Service on telephone number 028 90524480 .
- P. ramorum infection has been confirmed in Japanese larch trees (Larix kaempferi) in woodland managed by Forest Service and on a privately owned forest on the Antrim Plateau.
- P. ramorum can be spread on footwear, vehicle wheels, tools and machinery, by the movement of infected plants, and in rain, mists and air currents.
- Infected plants such as Rhododendron are usually destroyed by burning or deep burial. Infected trees are usually felled to kill the living plant tissue on which the pathogen depends.
- P. ramorum is a ‘quarantine’ organism under European Union Plant Health legislation and its presence on trees or woodland plants must be notified to the relevant authorities (DARD).
- Infected Japanese larch trees produce particularly high levels of inoculum that spreads the disease – five times the level produced on rhododendron - meaning the disease can quickly affect a large number of trees and shrubs.
- P. ramorum has not been found infecting any European larch (Larix decidua) or hybrid larch (Larix x eurolepsis) trees, but these species will be kept under close surveillance.
- There are approximately 2,500 hectares of Japanese larch or woodland with a Japanese larch component in DARD woodland in N Ireland which represents about 4% of DARD woodland area.
- P. ramorum causes the disease known as “sudden oak death” in the USA, where it has killed millions of American native oak and tanoak trees in California and Oregon. However, that populist term is not appropriate for here, as laboratory tests have shown that UK’s two native species of oak, sessile and pedunculate oak are much more resistant to it than their American cousins.
- The Plant Health Order (Northern Ireland) 2006 requires the containment and eradication of plant material infected by listed pests and diseases. DARD Forest Service inspectors have the power to serve Detention or Destruction Notices and to take steps to ensure that the infection is contained, eradicated or treated. If the owner of the premises in question fails to comply with such a notice, under Article 37 of the Plant Health Order the inspector is permitted to take such steps as are necessary to ensure compliance with the requirement of the notice. This includes destruction or removal of infected plant material.
- Pictures of symptoms of P.ramorum infection on Japanese larch can be found at:
- Further information on the disease is available on the internet at:
- All media enquiries to DARD Press Office, tel: 028 9052 4619. Out of office hours please contact the Duty Press Officer via pager number 076 9971 5440 and your call will be returned.
