Robert A. Spotts, primary collator (last update 3/13/93)
BACTERIAL DISEASES
- Crown gall
- Agrobacterium tumefaciens (Smith & Townsend) Conn
- Fire blight
- Erwinia amylovora (Burrill) Winslow et al.
- Pseudomonas blossom blast and canker
- Pseudomonas syringae pv. syringae van Hall
FUNGAL DISEASES
- Alternaria fruit rot
- Alternaria spp.
- Anthracnose canker and bull's-eye rot
- Pezicula malicorticus (H. Jacks) Nannf.
- (anamorph: Cryptosporiopsis curvispora (Peck) Gremmen in
Boerema & Gremmen)
- Armillaria root rot (shoestring root rot)
- Armillaria mellea (Vahl:Fr.) P. Kumm.
- (anamorph: Rhizomorpha subcorticalis Pers.)
- Bitter rot
- Glomerella cingulata (Stoneman) Spauld. & Schrenk
- (anamorph: Colletotrichum gloeosporioides (Penz.) Penz. &
Sacc. in Penz.
- Black rot, leaf spot and canker
- Botryosphaeria obtusa (Schwein.) Shoemaker
- (anamorph: Sphaeropsis malorum Berk.)
- Black spot (of Japanese pear)*
- Alternaria alternata (Fr.:Fr.) Keissl.
- Blister canker
- Helminthosporium papulosum Berg.
- Blister disease*
- Coniothecium chromatosporum Corda
- Blue mold rot
- Penicillium spp.
- P. expansum Link
- Botrytis spur and blossom blight
- Botrytis cinerea Pers.:Fr.
- (teleomorph: Botryotinia fuckeliana (de Bary) Whetzel)
- Brown rot
- Monilinia fructicola (Wint.) Honey
- M. laxa (Aderh. & Ruhl.) Honey
- Cladosporium fruit rot
- Cladosporium herbarum (Pers.:Fr.) Link
- (teleomorph: Mycosphaerella tassiana (De Not.) Johans.)
- Clitocybe root rot (mushroom root rot)
- Armillaria tabescens (Scop.) Dennis et al.
- = Clitocybe tabescens (Scop.) Bres.
- Coprinus rot
- Coprinus psychromorbidus Redhead & Traquair
- Dematophora root rot (Rosellinia root rot)
- Rosellinia necatrix Prill.
- (anamorph: Dematophora necatrix R. Hartig)
- Diplodia canker
- Botryosphaeria stevensii Shoemaker
- = Physalospora malorum Shear et al.
- (anamorph: Diplodia mutila (Fr.:Fr.) Mont.)
- Elsinoe leaf and fruit spot
- Elsinoe piri (Woronichin) Jenk.
- (anamorph: Sphaceloma pirinum Jenk.)
- European canker
- Nectria galligena Bres. in Strass.
- (anamorph: Cylindrocarpon heteronemum (Berk. &
Broome) Wollenweb.)
- Fabraea leaf and fruit spot
- Diplocarponmespili (Sorauer) Sutton
- = Fabraea maculata Atk.
- (anamorph: Entomosporium mespili (DC.) Sacc.)
- Fly speck
- Schizothyrium pomi (Mont.:Fr.) Arx
- (anamorph: Zygophiala jamaicensis E. Mason)
- Gibberella canker
- Gibberella baccata (Wallr.) Sacc.
- (anamorph: Fusarium lateritium Nees:Fr.)
- Gray mold rot
- Botrytis cinerea Pers.:Fr.
- Late leaf spot
- Cercospora minima Tracy & Earle
- Mucor fruit rot
- Mucor spp.
- M. piriformis E. Fischer
- Mycosphaerella leaf spot (ashy leaf spot and fruit spot)
- Mycosphaerella pyri (Auersw.) Boerema
- = M. sentina (Fr.:Fr.) Schrot.
- (anamorph: Septoria pyricola (Desmaz.) Desmaz.)
- Nectria twig blight (coral spot)
- Nectria cinnabarina (Tode) Fr.
- (anamorph: Tubercularia vulgaris Tode)
- Pear scab
- Venturia pirina Aderh.
- (anamorph: Fusicladium pyrorum (Lib.) Fuckel)
- Perennial canker
- Neofabrae perennans Kienholz
- (anamorph: Cryptosporiopsis perennans (Zeller & Childs)
Wollenweb.)
- Phyllosticta leaf spot
- Phyllosticta sp.
- Phytophthora crown and root rot (sprinkler rot)
- Phytophthora cactorum (Lebert & Cohn) J. Schrot.
- Pink mold rot
- Trichothecium roseum (Pers.:Fr.) Link
- = Cephalothecium roseum Corda
- Powdery mildew
- Podosphaera leucotricha (Ellis & Everh.) E.S. Salmon
- Pythium dieback
- Pythium spp.
- Rhizopus rot
- Rhizopus stolonifer (Ehrenb.:Fr.)Vuill.
- Rust, American hawthorne
- Gymnosporangium globosum (Farl.) Farl.
- Rust, Kern's pear
- Gymnosporangium kernianum Bethel
- Rust, Pacific Coast pear
- Gymnosporangium libocedri (C. Henn.) F. Kern
- Rust, pear trellis (European pear rust)
- Gymnosporangium fuscum R. Hedw. in DC.
- Rust, Rocky Mountain pear
- Gymnosporangium nelsonii Arth.
- Side rot
- Phialophora malorum (M.N. Kidd & A. Beaumont) McColloch
- Silver leaf
- Chondrostereum pupureum (Pers.:Fr.) Pouzar
- Sooty blotch
- Gloeodes pomigena (Schwein.) Colby
- Thread blight (Hypochnus leaf blight)
- Corticiumstevensii Burt
- = Pellicularia koleroga Cooke
- = Hypochnus ochroleucus Noack
- Valsa canker
- Valsa ceratosperma (Tode:Fr.) Maire
- (anamorph: Cytospora sacculus (Schwein.) Gvritischvili)
- Wood rot
- Trametes versicolor (L.:Fr.) Pilat and various basidiomycetes
- Xylaria root rot
- Xylaria spp.
MISCELLANEOUS DISEASES OR 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
- Core 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
- Xiphinema americanum Cobb.
- Dagger
- X. riveri Dalmasso
- X. vuittenezi Luc et al.
- Lesion
- Pratylenchus spp.
- P. penetrans (Cobb) Filipjev & Schuurmans-Stekhoven
- Pin
- Paratylenchus spp.
- Root-knot
- Meloidogyne spp.
VIRUSLIKE DISEASES
(Also mycoplasmalike organism [MLO])
- Flemish beauty corky pit
- Virus suspected
- Pear blister canker
- Virus suspected
- Pear decline
- MLO
- 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
*Not known to occur naturally on pear in the United States.
