SCOTLAND is gearing up for a summer invasion of leather-jacketed vandals that will terrorise parks, football and rugby grounds and farmland.

The threat comes from ­leatherjackets - the name given to the grubs of crane flies or daddy longlegs.

They live just below soil level and from August to June each year eat the roots of grasses and other plants, causing headaches for farmers and groundsmen. A survey carried out in west and central Scotland by experts from Scotland's Rural College indicates the number of the insect pests puts farmland, golf courses and other large areas of grass at extreme risk of damage.

Professor Davy McCracken, the SRUC ecologist leading the survey, said: "While over 90% of the fields sampled contained more than 0.6 million grubs per hectare, nearly 60% of the fields harboured populations of over two million per hectare. Densities like that, if left untreated, are likely to result in severe and visible damage to the grass sward or any spring crops sown after the grass."