| Kingdom: Monera |
| Phylum: Proteobacteria |
| Class: Gammaproteobacteria |
| Order: Enterobacteriales |
| Family: Enterobacteriaceae |
| Genus: Erwinia |
| Subject: Erwinia amylovora (Burrill) Winslow |
| Kingdom: Plantae |
| Phylum: Magnoliophyta |
| Class: Magnoliopsida |
| Subclass: Rosidae |
| Order: Rosales |
| Family: Rosaceae |
| Genus: Cydonia |
| Subject: Cydonia oblonga P. Mill. |