Scientists and MPs call for testing of ash disease treatment The treatment, developed by Natural Ecology Mitigation Ltd and Imperial College London, is currently awaiting trial by the Forestry Commission. It works on the basis that copper ions, the active ingredient, are mixed with nitrates and phosphates so that the tree absorbs the fungicide as a nutrient and spreads it throughout its system. The solution can be sprayed over wide areas from an aeroplane or cherry picker or applied directly to the leaves or tree roots. Joan Webber, principal pathologist at the Forestry Commission, confirmed that the treatment had proved effective against horse chestnut bleeding canker in trees but could not say whether it would work against the ash dieback fungus before she had seen the data from trials. A spokesman for the Department for Environment, Food and Rural Affairs and the Forestry Commission said the departments did not have "sufficient evidence" about the effectiveness of the treatment. He said: "We will be monitoring any scientific developments that might help us tackle chalara. This compound is one of a number of products currently being promoted by companies. The testing process is necessarily long and rigorous and is funded by the developer. The funds and processes have not been fully put in place with Forest Research to test this product against Chalara fraxinea.