Curled leaves
These tightly curled leaves on Hawthorn (Crataegus monogyna) are caused by the mite Phyllocoptes goniothorax.
Hawthorn button-top gall
These untidy clusters of leaves at the end of a stem are caused by the gall midge Dasineura crataegi.
Rust fungus on leaves
This gall is caused by a rust fungus. The fungus is either Gymnosporangium clavariiforme or G. confusum.The spores of the fungi must be examined to distinguish the species. The actual galls are the yellowish mounds on which the antler-like horns are protruding from. The ”horns” themselves are the part of the fungus that will release its spores into the air. These fungi have a complex life history and require Juniper plants as a primary host before spores are released to find a secondary suitable host such as Hawthorn or Rowan.
All photos – Ashley Watson.
Adventures of a WildLife 