27 February 1998

Hat-trick for leatherjackets

A THIRD year of leatherjacket damage is on the cards for arable crops following grass.

"With the mild weather, they could appear anywhere," warns ADAS entomologist Jon Oakley.

He has just produced a survey that suggests the warm wet conditions last autumn were particularly favourable to the pest in the midlands and north-west, giving an average population of a million larvae a hectare.

"The tricky bit will be assessing the risk to spring cereals," he says. "The chances are your agronomist looked at them last week, since when they will have stopped feeding on buried turf and turned their attention to the growing crop."

Look for the tell-tale signs of bird activity and keeled-over shoots, he advises. A total of 15 leatherjackets along 10 different 30cm (1ft) lengths of row means the pest is at threshold levels and it is worth a spray.