It is regarded as the ultimate enemy of newly planted young trees in Scotland.

The large pine weevil is a serious pest of conifer forests across the whole of Northern Europe, wherever clear-felled sites are replanted.

In the past, controversial chemical pesticides have been used in a bid to control the beetle, whose Latin name is Hylobius abietis.

But efforts are under way to reduce the use of powerful insecticides and find new strategies to manage the threat, with five firms each awarded up to £30,000 research funding to develop environmentally-friendly techniques to thwart the weevil.

Adult large pine weevils are drawn to the stumps of newly felled conifers, in which they lay their eggs and then emerging adults feed off the bark of the newly planted seedlings, which they can kill.

Heavy feeding leads to the eventual death of the trees.

Tackling the issue is a key challenge for forestry, with previous techniques primarily concentrated on insecticide use, which ultimately sparked environmental concern.

Nicotine-based insecticide, acetamiprid, is in widespread use, with hundreds of kilograms sprayed across Scotland’s forests every year.

Acetamiprid is one of a group of manufactured neonicotinoid chemicals lethal to insects. 

A ban on all outdoor use of three neonicotinoids was agreed by the European Union in April last year due to evidence showing they could endanger bees and other pollinators – but this did not include acetamiprid.

Forestry Commission Scotland (FCC) said 196 kilograms of acetamiprid were sprayed on 711 hectares of public woodland last year. 

Forest Enterprise Scotland said of chemical use that the default position was “not to use them unless necessary”, while aware that “if we didn’t use this protective measure the losses to the forest industry would be massive – around 50 per cent of planted trees would be lost”.

Now the five companies – applicants to an open innovation competition from Forest Enterprise Scotland and launched by Rural Economy Secretary Fergus Ewing last year – are looking to develop alternatives to current chemicals to deal with the pest, the impact of which is huge.

Each year, the pine weevil is estimated to cause direct losses of around £5 million to forestry across the UK, as well as causing significant delays to the re-establishment of future forest crops.

Outlining the threat posed, George Anderson, of Woodland Trust Scotland, said the large pine weevil is in fact “one of the biggest challenges to commercial foresters across Europe”.

He added: “The nature of commercial plantations collide with the lifecycle of the beetle to unfortunate effect. 

“The weevils breed in the stumps and roots of trees which have been felled, so when an area is clear felled there can be an explosion in the pests. When the next crop of new young trees is planted they get mauled by the adult beetles, which eat the bark around the base of the stem.

“The weevils live for years so this is a massive problem in commercial forestry operations which want to get the next crop of trees in as soon as possible after felling.”

Welcoming the announcement of the research grant awards Mr Ewing said: “The pine weevil is a serious threat to the economic, social and environmental benefits that forestry provides. Developing innovative and successful solutions to tackle this serious pest of young trees is imperative for the health public and private woodlands across Scotland.”

The companies now have five months to develop and prove their ideas, in a bid to win further funding of up to £200,000.