Contexte

Leatherjackets (the larvae of crane fly) feed on the roots and stems of grass or cereal plants and can cause significant damage from loss of yield and the presence of large bare patches. In particular, grass reseeds and new leys can be devastated if leatherjackets are not controlled. Grassland covers 92% of the utilised agricultural area in Northern Ireland and is the principal and cheapest feed for the ruminant livestock sector. The destruction of grass by leatherjackets can therefore have a significant effect on the profitability of dairy, beef and sheep farms. For the past 40 years leatherjackets were controlled by agrochemicals containing chlorpyrifos (e.g. Dursban), however, approval for use of products containing this active substance in grassland was withdrawn in 2016. A move to pre-emptive mitigation strategies is required but there is very little currently known about this or their effectiveness.