Dichotomous table for gallers on Forsythia
by Hans Roskam
1a On parts above ground => 2
1b Roots with nodular, compact swellings. F. x intermedia: Meloidogyne hapla
2a Galls on twigs => 3
2b Leaves on shoot tips ± disfigured, caused by aphids. F. suspense: Unidentified aphid
3a Rotund galls, usually situated on nodes, developing into strongly fissured woody proliferations, up to several cm large. F. suspense: Agrobacterium tumefaciens
3b Conspicuous, ± wart-like, at first succulent, later on tough galls of variable size, which develop on young shoots instead of lateral buds. Rhodococcus fascians