Leatherjackets are causing significant challenges for farmers in the western region of Northern Ireland as they struggle to manage the pest without the availability of chemical control substances.

The challenge of leatherjacket presence in grassland was the focus of a recent webinar held by AgriSearch as part of the Leatherjacket Mitigation Strategies European Innovation Partnership (EIP) project.

Funded by the European Agricultural Fund for Rural Development (EAFRD) and the Department of Agriculture, Environmental and Rural Affairs (DAERA), the project is led by four Fermanagh-based farmers as well as AgriSearch.

Leatherjackets, which are the larvae of crane flies, have a typical life cycle of approximately 11 months, and can cause extensive damage to grasslands by living under the soil and feeding off the roots of grass, cereals, and root vegetable crops.

The webinar placed a special emphasis on the impact of leatherjackets and the possible mitigation methods currently being explored. The latter topic was a particular focus given the absence of chemical pesticides.

The last number of years have seen a major decrease in the number of chemical insecticides approved for commercial use by the European Commission, largely due to their impact on the environment.

Prof. Rod Blackshaw, soil ecologist and researcher, spoke about the history of leatherjacket presence as well as the risk protection models. According to him, there is now a need to move towards a multi-year management approach rather than a control approach.

PhD student with Teagasc and the University of Edinburgh Aisling Moffat, also attended the webinar. She presented a summary of outcomes from research she carried out that looked at leatherjackets as an agricultural pest in the Republic of Ireland and potential integrated pest management (IPM) solutions.

Results from a survey were presented during the webinar, alongside soil factors which have been found to be of importance. Initial results indicate that pH, magnesium and phosphorus are significantly correlated to leatherjacket populations with higher larval populations also found in acidic soils.

Following this, initial results from a multi-species sward trial were also presented which showed that no significant yield losses are being seen despite leatherjacket presence. It was suggested that this could perhaps be a result of increased diversity in the sward.  

Jillian Hoy, research manager with AgriSearch closed the event by presenting the results of a Northern Ireland online survey issued in 2021 by the EIP group. The results confirmed higher incidences of leatherjacket presence in western counties with more regular occurrence also a feature.

According to Hoy, presence tended to occur in only a few fields across all respondents with no correlation between affected fields being obvious to many of them. Despite this however, the presence of leatherjackets in most cases was found to significantly impact grass growth.