Chalara fraxinia has now been confirmed in a number of locations across the UK especially in East Anglia, our nearest case was in Braintree. But what exactly is it? the disease is caused by the fungus Chalara fraxinia and it causes loss of leaves,dieback of the crown and can lead the tree to die. It has in the past infected many species of ash but with differing intensities. As some ash species show very few symptoms after infection, they may act as undetected carriers. Unfortunately Common ash Fraxinus Excelsior is the most severely affected species. Young trees are particularly vulnerable to Chalara fraxinia and succumb to the disease rapidly. There is no evidence that Chalara fraxinia can spread to tree species other than ash or that it is harmful to the health of people or animals.
Infection is via spores from fruit bodies on leaf litter. Spore production in fruit bodies occurs on infected fallen leaves and shoot material in the growing season after infection, trees are likely to need a high dose of spores to become infected. Chalara fraxinia causes infection from June to October, mainly in July to August. Moist conditions favour production of the fruiting bodies.
How does Ash dieback Chalara fraxinia spread?
Spores are produced on Chalara fruit bodies formed on fallen leaves and shoots the year after becoming infected. Natural spread is by wind blown spores from these fruit bodies. Wind blown spores may be dispersed up to 12-18 miles. Longer distance infection occurs via infected plants or potentially via wood products. There is a low probability of dispersal on clothing and footwear or via animals and birds. There is a lower risk of Chalara fraxinia spreading over the winter as there is now a ban on ash imports into the UK, restrictions on plant movements through Statutory Plant health notices and as spore production is not expected to resume until June 2013
Trees cannot recover from infection but larger trees can survive infection for a considerable length of time and some may not die.
For an informative film on Chalara fraxinia please follow this link:
The Forestry Commission has also published a new, improved pictorial guide to the symptoms of Chalara fraxinea infection, at www.forestry.gov.uk/chalara
The latest forestry commission video on identifying ash dieback in spring can be found here: http://youtu.be/UuU8_e0Vw8Q
For any further info on the disease Chalara Fraxinea please give us a call