Acari: Eriophyoidea - gall mite Eriophyes laevis Photographs on Alnus glutinosa, Common Alder Hosts: Alnus glutinosa, incana Can be numerous on upper surface of leaves with small opening on underside. Galls initially yellow-green becoming red or brownish with age. The mite Diptacus sacramentae is uaually a vagrant forming light, brown spots on underside of leaves but sometimes occurs as an inquiline in E. laevis galls

Eriophyes laevis
Studland Heath, Dorset. September 2013