ear cockle
/ˈɪə kɒkl/noun
A disease of wheat and other cereal plants caused by the parasitic nematode Anguina tritici, in which the grains are replaced by small, dark galls. Also (in plural): the galls themselves.
Origin
Late 18th century; earliest use found in The Gentleman's Magazine. From ear + cockle, possibly after the resemblance of the galls to the black seeds of the corncockle, Agrostemma githago.