Pine Weevil Integrated Pest Management Conference

A Teagasc conference on ‘Pine Weevil Integrated Pest Management’ was held on Wednesday, 4th May at the Tullamore Court Hotel. It focused on current issues with pine weevils in Irish forestry and integrated Pest Management (IPM) options for controlling the pest.

Pine Weevil Integrated Pest Management Conference

The event included talks from Irish and UK experts on a number of topics including pine weevil IPM, reforestation and continuous cover forestry, pesticide registration, regulations and future outlooks, pine weevil forecasting and the UK experience.

The large pine weevil (Hylobius abietis) can cause very substantial plant mortality in reforestation sites. Felling a coniferous crop produces a large increase in breeding material for the pine weevil, whilst plant material suitable for adult feeding is reduced. Young trees (both conifer and broadleaf) used for restocking are liable to be heavily attacked by adult pine weevils feeding on the stem from the root collar upwards. Heavy damage can completely girdle stems and cause plant death.

It is estimated that on average 50% of the young trees on untreated sites in Ireland and the UK are killed by pine weevil during the first few years. This will increase the re-establishment costs substantially through the cost of insecticide application, replacing plants and additional weeding.

Nuala NiFhlatharta, Head of the Teagasc Forestry Development Department, who chaired the event said; “The large pine weevil is the most important reforestation pest in Ireland. Pine weevils kill about 50% of unprotected seedlings”.

Dr Louise McNamara, Entomology Research Officer with Teagasc spoke about pest management options and added; “High numbers of pine weevils in Ireland makes control more challenging, with physical protections often not enough on high pressure sites, meaning we will still require pesticides in the future.”

John Casey, forestry advisor, Teagasc, added; “One third of reforestation costs could be down to Pine weevil control. While cost is high, the potential cost of failure and replanting is higher.”

Colm Lyons, Coillte, highlighted that “Green planting or ‘hot planting’ has had a very positive effect on reducing pine weevil damage and has the effect of reducing insecticide use”. Padraig O’Tuama, Private Forestry Consultant, added; “Continuous Cover Forestry management greatly reduces the risk of pine weevil being an issue in the forests in Ireland”.  

Professor Christine Griffin, Maynooth University gave updates on current research on pine weevil forecasting and modelling and added; “field trials have shown that nematodes can reduce pine weevil populations by up to 80% but operational challenges may restrict their widespread use in Irish reforestation.”

The conference was organised as part of the PW-IPM project funded by the Department of Agriculture, Food and the Marine (DAFM), involving Teagasc and Maynooth University as partners. Find out more about Pine Weevil here https://www.teagasc.ie/crops/forestry/advice/forest-protection/large-pine-weevil/