'Sudden oak death' disease found in trees here


“SUDDEN OAK Death” disease, which killed off considerable numbers of native trees in north America, has been identified here for the first time, in Tipperary and Waterford.

Only a year after it was found in Britain, the disease, Phytophthora ramorum, has been found in Japanese larch trees in the Tipperary/Waterford area by Department of Agriculture scientists.

The disease is caused by a fungus-like organism and has also been identified in beech trees and two noble fir trees growing in proximity to the infected larch trees here.

“Sudden Oak Death” disease causes “bleeding cankers”, or oozing lesions, on the trunks of infected trees, necrosis (dieback) of leaf tips, and stem wilt and stem lesions on infected shrubs and plants, and some trees.

It is spread through the air, probably in rain-splash and mist-laden winds, or via watercourses. It can also be spread through human and animal movements.

In a statement yesterday, the department said that following findings of the pathogen in Japanese larch trees in Britain last autumn, the department had initiated a survey here of Japanese larch growing adjacent to areas where rhododendron infected with P ramorumhad already been detected.

Scientists in Britain who have been working to prevent its spread believe the key lies in the removal of rhododendron host plants, and the timely eradication of infected plants capable of producing inoculum.

This reduces the number of spores produced that could be spread to surrounding trees by rain-splash or the movement of infected plants.

The department said it was taking all necessary measures to establish the extent of the infection and to control the spread of the disease, as it had also been found in Northern Ireland.

Japanese larch trees represent some 3 per cent of the total forest tree population in Ireland. The bulk of the wood from infected trees can be used in the normal way provided the necessary hygiene measures are taken at felling and in sawmills.

According to the forestry commission website in Britain, P ramorumgot its nickname in the United States because it has killed significant numbers of North American native oak ( Quercus species) and tanoak trees ( Lithocarpus densiflorus, which are not true oaks at all).

“However, Britain’s two native oak species have proved to be much less susceptible than their American cousins,” it stated.