pathological formation on the leaves of the bush - gall

agriculture ailment background blade blast bloodsucker botany branch bulging closeup cocoon cycle disease excrescence fly folio folium gall garden green grower growth herb illness knot leaf leaflet leaves life malady microorganisms nature neoplasms organic outgrowth parasite pathogenic pathology pest plant plate rag red sheet sickness slip sponge sponger sucker summer the tree trouble