| 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: Pyrus | 
| Subject: Pyrus calleryana Decne. |