Identification and distribution of leatherjackets (Tipula spp.) in the Republic of Ireland

Abstract

The soil-dwelling larval stage of crane flies, commonly known as leatherjackets, are classified as agricultural pests in Europe, and pests of turf in North America and Canada. They cause significant damage and yield loss in many cropping systems through their feeding on plant roots and stems at ground level. The effective chemical control for these pests, chlorpyrifos (available since 1965), was prohibited across Europe in 2019. This has left severely restricted control options for growers. Unlike Northern Ireland and Great Britain, no leatherjacket surveys or routine identifications have been conducted across Ireland. Therefore, the leatherjacket species of agronomic importance has not been confirmed. Since lifecycles, feeding behaviour and damage periods differ between species, identifying the most common species is a vital first step in any pest management strategy. Here we report key findings from a 2-yr structured survey of Irish crops, conducted in 2019 and 2021, where 135 sites were sampled. Both grassland and cereal crops were inspected. Soil cores and soil samples were collected and larval abundance determined. The European crane fly, Tipula paludosa Meigen, accounted for approximately 70% of larvae collected and identified (n = 337). In 2019, 40% of grasslands exceeded the threshold of 1 million larvae/ha, while only 3.3% of cereal fields were over the threshold of 600,000 larvae/ha. These results indicate that agricultural grasslands in Ireland have the potential to be significantly impacted by leatherjacket damage, although this may vary temporally and geographically across the island. Without effective control options, yield losses will be highly probable.