Wasp threat to oaks highlighted by RHS expert

A small wasp is having a detrimental effect on oak trees in the county of Shropshire, it has been reported.

Shropshire Star reader John Beech, who hails from Telford, has written in to express his concern about the plight of an oak tree in his garden which has started to warp and is producing misshapen acorns.

This phenomenon has been attributed to the knopper gall wasp, which damages acorns when it lays its eggs in them.

According to the Royal Horticultural Societys (RHS) Andrew Salisbury, it is not just oak trees in Shropshire that are at risk from the knopper gall wasp – its oaks up and down the country.

"This poses a serious long-term threat to oak trees. In some areas almost all oaks have been affected," he told the newspaper.

The problem has been compounded by the wet summer, the expert warned.

Other risks to oak trees include Sudden Oak Death (Phytophthora ramorum), a water mould that can prove fatal inside a few weeks, and Oak Wilt, which is caused by the fungus Ceratocystis fagacearum.