You may have got used to the scientific name for Ash dieback, Chalara fraxinea. This is how it has been routinely described since the current outbreak became a matter for widespread concern. However under a review of the correct naming procedures for funghi, it is now correctly termed Hymenoscyphus fraxineus.
Perhaps the layman (and laywoman) will find it easier to stick with Ash dieback, but professionals will find it appropriate to use the scientific term, so it as well to at least know that the two terms refer to the same thing.
You may find helpful the information via this link to the Forestry Commission