Scientists Battle Tiny Invader Devouring Ash Trees

Scientists are implementing a three-year research project to protect native ash trees from the invasive ash sawfly. The sawfly larvae, which feed on tree leaves between May and June, can completely strip trees bare. This defoliation expends significant energy from the trees, slowing their growth and making them more susceptible to other pests and diseases, including the fungal disease ash dieback. The insect, harmless to humans, is believed to have arrived in Northern Ireland from mainland Europe in 2016.

Traps have been deployed as part of the project, particularly in the Belvoir forest area of Belfast. These traps, often sticky and yellow, are designed to attract and capture adult sawflies, disrupting their life cycle and reducing next year's population. Ground cover traps using mesh are also being tested. An earlier study found that 90% of trees surveyed along Belfast's Lagan Towpath showed signs of sawfly damage between 2019 and 2021.