Keeping woodlands in Wales and Ireland healthy


Integrated Pest Management is paying off in the forests of Wales (26-05-2015)

Pest control measures within an Integrated Pest Management approach being carried out by forest scientists in Wales are paying off, helping to secure the future of the timber sector.
Pest control measures within an Integrated Pest Management approach being carried out by forest scientists in Wales are paying off, helping to secure the future of the timber sector.

That was the message from IMPACT, the EU-funded joint Ireland-Wales project which looks at tree pests and climate change, at an important international conference held at Bangor University.

Forest Research in Wales, which co-ordinates the project, has carried out a Wales-wide monitoring programme demonstrating that, even in some of the most far-flung forests of the principality, the battle against important insect pests to protect commercial forestry is being won.

"This proactive action, monitoring the forests to see whether some of the pests on our ‘not wanted’ list have migrated here, has given us a clearer understanding of what is happening on the ground ," said project leader Professor Hugh Evans of Forest Research in Wales.

"This knowledge enables us to provide advice to foresters to help them combat pests, old and new It is vital work which will help with planning any possible counter-measures, and is essential to the future health of our forests.”

He explained that Forest Research had worked with foresters to release a host-specific predatory beetle, Rhizophagus grandis, for ‘classical’ biological control of one of the biggest threats to commercial forestry, the great spruce bark beetle (Dendroctonus micans), an exotic pest from the European mainland.

Without that control, many commercial spruce forests across the country would have been badly affected, killing thousands of trees and reducing returns for the forestry sector.

The biological control programme has been highly successful because of the extraordinary ability of the predator to locate its prey, even when there may be only a few infested trees in the forest. Foresters have been releasing the tiny bark beetle killer whenever they find the beetle itself.
For more than 20 years Rhizophagus has been moving through the forests in balance with its prey to prevent a major increase in the pest population, and the IMPACT project has found that the balance is being maintained.
"Dendroctonus has spread through much of the spruce forests of Wales, but its numbers are contained by its predator," IMPACT project manager Tim Saunders told conference delegates.

"After a series of field observations we now know that current controls are working, even in the furthest corners of Wales, including Pembrokeshire and the Lleyn peninsula."

It was also thought that Welsh forests could be at risk from the large larch bark beetle (Ips cembrae) and, as part of safe-guarding the future of Wales' larch trees, the team from the IMPACT project carried out a two-month monitoring programme.

This beetle has already been found in the Forest of Dean, and they were investigating to see whether larch trees, already weakened in Wales by the fungus-like Phytophthora ramorum organism, were attracting this new pest.

"We are pleased to report that we didn't find any evidence of a breeding population of the beetle here in Wales," said Tim. "As part of our wider survey effort, we have also confirmed that Welsh forests are still free of spruce saw fly (Gilpinia hercyniae), which caused massive loss of foliage of spruce trees in the 1970s, but was reduced to undetectable levels through use of a naturally occurring virus specific to this pest species."

Meanwhile, the use of biological controls, nematodes coupled with fungi, is helping reduce numbers of potentially the most damaging and costly pest of UK and Irish forests, Hylobius abietis.

The microscopic nematode worms are entomopathogenic (insect-killing), attacking and killing the larvae, pupae and young adult Hylobius, reducing the pest population in Welsh forests by up to 90 per cent, where they are applied.

Joint work by IMPACT partners Forest Research and Swansea University over the last five years has enabled the 'kill rate' of this tree-eating weevil to be increased - whilst also cutting costs.

"Through a series of trials we have shown that we can use a lower concentration of the nematode and fungal agents in treating threatened areas, which has an important impact financially, reducing expenditure by up to 20 per cent," said Professor Tariq Butt of Swansea University.

Similar results were reported by IMPACT partners from Maynooth University in Ireland, using a similar management strategy. Working closely with Natural Resources Wales, these results confirm and strengthen the Welsh use of nematodes to combat Hylobius.

The five-year project, which finishes in June, is now finalising its own list of potential threats, working on the UK Plant Health Risk Register, and also adding potential new threats, enabling foresters and scientists to continue with the fight to prevent any new tree threats developing in Wales. (Is it one, the other, or both?)

Other key areas of research includes the development of a Pine Wood Nematode control toolkit; work looking at the control of invasive species; ticks, midges and other biting insects; the spread of Horse Chestnut Leaf Miner, and many others pests.

The IMPACT team is led by Forest Research in Wales, and includes the National University of Ireland, Maynooth and Swansea University.


Professor Hugh Evans, Forest Research in Wales: Tel – 07917 000234


IMPACT – Integrated Management of forest Pests Addressing Climate Trends:
Is part funded by the European Regional Development Fund (ERDF) through the Ireland - Wales Programme (INTERREG 4A) and part funded by Natural Resources Wales and the Forestry Commission. It is led by Forest Research in Wales, a research unit launched in 2009 based at Aberystwyth, with the National University of Ireland at Maynooth and Swansea University. It runs to 30 June 2015.

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