If WEATHER problems this spring have not made life difficult enough for cereal growers and grassland farmers, yesterday produced a warning that both grain and grass crops are under considerable threats from leatherjackets.
According to SRUC (Scotland’s Rural College), populations of this pest, which can devastate crops by eating the roots of plants, are at their fourth-highest level since SRUC first started testing for them almost 40 years ago.
Leatherjackets are the grubs of the crane fly or “daddy-long-legs” and, according to SRUC ecologist Dr Davy McCracken, more than 80 per cent of the fields sampled had populations in excess of 0.6 million larvae per hectare and nearly 70 per cent had populations of over a million per hectare.
“The winter weather may have caused us problems but the grubs are very resilient and all they do in cold weather is reduce their feeding until the soil warms up again,” he said. “Land in the south and west covered by our SAC consulting offices is at risk, including permanent grassland and spring crops sown after grass.”
Ideally chemical treatment should take place before the land is ploughed but in targeting their pesticide programme McCracken warned farmers to take account of the soil temperature.
“Treatments should be applied as soon as conditions allow but that means considering more than whether it is dry enough. Insecticides to control leatherjackets can be less effective if the soil temperature is below 5C.”
He said many crops treated early this season may not have produced effective results.