Ash Dieback is caused by the fungus Hymenoscyphus fraxineus, which first destroys the leaves followed by branches, trunk, and finally the entire tree.
First discovered in 2012 as a result of imported infected trees it is now in Suffolk and Norfolk to south Wales.
There are disease resistant cultivars that resist ash dieback but can do nothing to resist the following.
In Europe a second more deadly assailant on the trees is the Emerald Ash Borer,a green beetle whose larvae bore into the wood, killing the trees.
It has not reached Britain yet but is moving eastwards from Russia at 25 miles per year,having now reached Sweden, meaning it is only a matter of time before we can expect the beetle over here.
The Ash is second only to Oak in numbers with over 2 million trees in and around cities, let alone how many are in woodland, so the demise of the Ash will have a major impact on biodiversity which is why I decided to have a quick look to try to ascertain how the situation would affect our butterflies and moths and was surprised by results.
With only about 700 species on the website I was surprised to find that only one moth relies entirely on Ash and that is the Centre-barred Sallow with Pseudargyrotoza conwagana larva feeding on Ash and European Barberry.
What can’t be checked are the numbers of moths whose larvae feed on Ash (23) and other plants, when the other plants don’t grow close to the Ash.
It would seem ironic as I look across the road from the cattle grid at Odiham Common at a single Ash tree with a row of Elms in the background that if the Ash tree goes I will have a clearer view of dying Elms.
Whatever the final result on biodiversity the thought of such a loss to our countryside is affecting me already.
The box tree moth Cydalima perpectalis first arrived in parts of England in 2008 at a commercial nursery before being recorded for the first time in a private garden in southeast England in 2011.
The 40mm wingspan moth deposits overlapping sheets of pale yellow eggs on the underside of box leaves with the resultant early stage larvae feeding on the underside of the leaves of Box (Buxus) leaving the upper epidermis intact. Later instars completely defoliate the leaves beneath a silken web clearly disfiguring any hedging or topiary, which is popular with this plant.
The moth was originally recorded in London but has now spread across south east England
As such the Royal Horticultural Society has nominated this moth as “top pest” for the first time above slugs and snails, which usually claim this spot. The RHS has requested on their website than anybody seeing any signs of any stage of this moth fill in this report at http://apps.rhs.org.uk/surveys/submitrecord.asp?type=9
Clearly global warming and importation of unchecked plant material is going to be in the news for many years to come.
Many thanks go to Tim Norriss for providing photos of the adult and larval stage of this moth