This week we have launched two new surveys at TreeWatch. Both relate to the health of our oak trees and we asking members of the public for their help. Both surveys have been developed jointly with scientists from Forest Research and we will be sharing the scientific data we collect them to help in their studies. Both surveys, the oak jewel beetle and powdery mildew, have been linked to the very serious problem affecting our oak trees:- Acute Oak Decline.
The oak jewel beetle Agrilus biguttatus, lays its eggs in crevices on the bark of native oak trees. The larvae that hatch then tunnel through the bark to feed on the tree tissues underneath the bark. If large numbers of this insect infest a tree it may lead to tree death. When the larvae pupate, the emerging young adult beetles make very characteristic ‘D’-shaped exit holes.
Scientists at Forest Research want to know more about the distribution of this beetle, so it is just as important that your report an absence as much as a presence!
The second new survey is on Oak powdery mildewsurvey. Powdery mildew of oak is caused by the fungus Erysiphe alphitoides (also known as Microsphaera alphitoides) and it is a common foliar pathogen of oak trees across Europe. First found in England in 1908, it is thought to have been a factor in an oak dieback episode in the 1920s. Scientists today believe that it may one of the factors that is contributing to the decline of our oak trees. The mildew attacks young leaves and soft shoots of oaks, covering them with a felty-white mycelium (fine white threads). It causes eventually the leaves to shrivel and dry out or turn brown.
If you can help us by monitoring the health of oak trees near you, please get involved. It is easy and fun. To find out more and to take part visit www.TreeWatch.com