Mycangial fungus benefits the development of a leaf-rolling weevil, Euops chinesis

► Removal of Penicillium herquei inocula decreased Euops chinesis survival rate. ► Inoculation with P. herquei decreased the cellulose content of the knotweed leaves. ► Penicillium herquei also showed antibiotic properties against two Rhizopus fungi.