Leatherjackets have become a major pest problem on many farms in western counties of Northern Ireland with varying degrees of damage to grassland.

The recent open meeting of Fermanagh Grassland Club sponsored by The Vaughan Trust heard from scientific researchers in Northern Ireland and the Republic of Ireland about the infestation of leatherjackets across the island of Ireland and how some farmers were dealing with them.

Aisling Moffatt, an agricultural entomologist, who has been studying Leatherjackets as part of her PhD based at Teagasc in Carlow, presented findings from her own work which indicated an economic threshold of the population level where yield loss equalled the cost of control needed.

In grassland this was shown to be one million larvae per hectare and in cereals, 600,000 larvae per hectare.

The leatherjacket species, Tipula Paludosa had one lifecycle during the year, with eggs hatching in August with most feeding of grass plants occurring during the spring months and then the adult insect, the cranefly or daddy long-leg emerging in late July. Another species, Tipula Oleraca, had two lifecycles a year.

Aisling explained that her PhD research objectives was to have a national survey of the Republic of Ireland of leatherjacket species and populations, compare the results to the Scottish Rural College results, look at how soil analysis affected infestations and give grassland sward advice.

The vast majority of the insect were the Tipula Paludosa species.

She revealed that grasslands were more vulnerable to high intensity pest attacks, that smaller fields might benefit leatherjacket larvae in terms of habitat and shelter and the importance of grass height during the pupation stage in July and August was highlighted.

Following various experiments, Aisling said they showed diverse swards had increased tolerance and compensatory factors.

Dr. Archie Murchie from AFBI, explained that the project he is involved in is part of the EIP programme across Europe.

He explained how a pesticide containing Chlorpyrifos which gave good control of the problem had been banned for use by the European Union since 2016 because of the safety risks to sprayer operators. He said without pesticide control, landowners needed to adopt an Integrated Pest Management system.

He said there was some form of biolological control by natural predators such as rooks or starlings or a species of wasp which lay their eggs inside the Leatherjacket eggs.

He showed some simple ways that farmers could sample their ground such as the use of brine pipes.

He said the pH of the soil influenced infestations with lower pH tending to lead to higher concentration levels. He said management techniques such as tightly grazing fields in late summer and early autumn was beneficial to keeping leatherjacket infestations lower.

In fields where there is some cultivation going to take place, ploughing was found to help break the leatherjacket lifecycle.