Leatherjackets could pose a risk to arable crops, particularly sugar beet and vegetables after grass, throughout May and growers should keep checking fields, advise experts.

Damage is showing up with increasing frequency across the eastern counties and is expected to continue until June when leatherjackets start pupating and feeding stops, according to Dow AgroSciences.

“Damage can be rapid with crops being written off within a few days of germination,” says the firm’s technical specialist Jim Butchart.

Norfolk-based AICC (Association of Independent Crop Consultants) agronomist Andrew Watson has seen bad leatherjacket damage in many crops following grass.

“One client had 20 acres of sugar beet totally written off within three days because of leatherjacket feeding. It has now been re-drilled and sprayed post-drilling with Dursban WG (chlorpyrifos).”

Mr Butchart recommends applying Dursban WG at 1.0 kg/ha as soon as treatment thresholds are reached and urges growers to use high water volumes, up to 400 litres/ha, to get the best results in dry conditions.