Elm yellows is a disease of elm trees caused by a type of bacterium known as a phytoplasma. Symptoms of the disease can range from yellowing of leaves to dieback of foliage and branches. Elm yellows has been found affecting elm trees in North America and a few European countries, but in 2014 it was detected in the UK for the first time on imported material being propagated at a nursery in England. It is important that any further suspected cases of the disease are reported, so that infected saplings are not planted in the wider environment giving the phytoplasma the chance to spread. Elm yellows can affect healthy elm trees that are resistant to other serious conditions such as Dutch elm disease.