Apple gall on Acacia longifolia from wasp species Trichilogaster acaciaelongifoliae .

''Trichilogaster acaciaelongifoliae'' is a species of Australian chalcid wasps that parasitises, among others, ''Acacia longifolia'' , which has become an invasive pest in several countries. ''T. acaciaelongifoliae'' has been introduced into South Africa as a generally successful biological control agent of ''A. longifolia''.