| Bacterial diseases | |
|---|---|
| Crown gall | Agrobacterium tumefaciens |
| Fire blight | Erwinia amylovora |
| Pseudomonas blossom blast and canker | Pseudomonas syringae pv. syringae |
| Pear decline | Phytoplasma |
| Fungal diseases | |
|---|---|
| Alternaria fruit rot |
Alternaria spp. |
| Anthracnose canker and bull's-eye rot |
Pezicula malicorticus |
| Armillaria root rot (shoestring root rot) |
Armillaria mellea |
| Bitter rot |
Glomerella cingulata |
| Black rot, leaf spot and canker |
Botryosphaeria obtusa |
| Black spot (of Japanese pear) | |
| Blister canker | |
| Blister disease | Coniothecium chomatosporum |
| Blue mold rot | |
| Botrytis spur and blossom blight |
Botrytis cinerea |
| Brown rot | |
| Cladosporium fruit rot |
Cladosporium herbarum |
| Clitocybe root rot (mushroom root rot) |
|
| Coprinus rot | |
| Dematophora root rot (Rosellinia root rot) |
Rosellinia necatrix |
| Diplodia canker |
Botryosphaeria stevensii |
| Elsinoe leaf and fruit spot |
Elsinoe piri |
| European canker |
Nectria galligena |
| Fabraea leaf and fruit spot |
Diplocarpon mespili |
| Fly speck |
Schizothyrium pomi |
| Gibberella canker |
Gibberella baccata |
| Gray mold rot | |
| Late leaf spot | |
| Mucor fruit rot |
Mucor spp. |
| Mycosphaerella leaf spot (ashy leaf spot and fruit spot) |
Mycosphaerella pyri |
| Nectria twig blight (coral spot) |
Nectria cinnabarina |
| Pear scab |
Venturia pyrina |
| Perennial canker |
Neofabraea perennans |
| Phyllosticta leaf spot |
Phyllosticta sp. |
| Phytophthora crown and root rot (sprinkler rot) | |
| Pink mold rot | |
| Powdery mildew | |
| Pythium dieback |
Pythium spp. |
| Rhizopus rot | |
| Rust, American hawthorne | |
| Rust, Kern's pear | |
| Rust, Pacific Coast pear | |
| Rust, pear trellis (European pear rust) | |
| Rust, Rocky Mountain pear | |
| Side rot | |
| Silver leaf | |
| Sooty blotch | |
| Thread blight (Hypochnus leaf blight) |
Corticium stevensii |
| Valsa canker |
Valsa ceratosperma |
| Wood rot |
Trametes versicolor |
| Xylaria root rot |
Xylaria spp. |
| Miscellaneous diseases and disorders | |
|---|---|
| Alfalfa greening (green stain) | Unknown |
| Bitter pit | Localized calcium deficiency |
| Black end | Water imbalance |
| Black speck (skin speckling) | Associated with low oxygen in storage |
| Blossom blast | Boron deficiency |
| Brown core | High CO2 |
| Core breakdown (Bartlett) | Senescence |
| Cork spot | Associated with calcium deficiency |
| Green stain | Unknown |
| Internal bark necrosis | Unknown |
| Mealy core (d`Anjou) | Senescence |
| Pink end (Bartlett) | Preharvest low temperature |
| Rosette | Unknown |
| Scald | Senescence |
| Nematodes, parasitic | |
|---|---|
| Dagger, American | |
| Dagger | |
| Lesion | |
| Pin |
Paratylenchus spp. |
| Root-knot |
Meloidogyne spp. |
| Viruslike diseases | |
|---|---|
| Flemish beauty corky pit | Virus suspected |
| Pear blister canker | Virus suspected |
| Pear decline | Phytoplasma |
| Pear freckle pit | Virus suspected |
| Pear red mottle | Virus suspected |
| Pear ring pattern mosaic | Virus suspected |
| Pear rough bark | Virus suspected |
| Pear stony pit | Virus suspected |
| Pear vein yellows | Virus suspected |
| Quince bark necrosis | Virus suspected |
| Quince sooty ring spot | Virus suspected |
| Quince stunt | Virus suspected |
| Quince yellow blotch | Virus suspected |
