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Diseases of Apple
(Malus × domestica Borkh.)

A. L. Jones, primary collator (last update 9/4/00)

BACTERIAL DISEASES

Blister spot

Pseudomonas syringae pv. papulans (Rose 1917) Dhanvantari 1977

Crown gall

Agrobacterium tumefaciens (Smith and Townsend 1907) Conn 1942

Fire blight

Erwinia amylovora (Burrill 1882) Winslow et al. 1920

Hairy root

Agrobacterium rhizogenes (Riker et al. 1930) Conn 1942

FUNGAL DISEASES

Alternaria blotch

Alternaria mali Roberts

= A. alternata (Fr.:Fr) Keissl, apple pathotype

Alternaria rot

Alternaria alternata (Fr.:Fr.) Keissl

American brown rot

Monilinia fructicola (G. Wint.) Honey

Anthracnose canker and bull's-eye rot

Pezicula malicorticis (H. Jacks.) Nannf

    Cryptosporiopsis curvispora (Peck) Gremmen in
    Boerema & Gremmen [anamorph]

Apple scab

Venturia inaequalis (Cooke) G. Wint.

    Spilocaea pomi Fr.:Fr. [anamorph]

Apple ring rot and canker

Botryosphaeria berengeriana De Not. (Japan, China)

= Physalospora piricola Nose

Armillaria root rot = shoestring root rot

Armillaria mellea (Vahl:Fr.) P. Kumm.

Bitter rot

Glomerella cingulata (Stoneman) Spauld. & H. Schrenk

    Colletotrichum gloeosporioides (Penz.) Penz. & Sacc.

    in Penz. [anamorph]

C. acutatum J. H. Simmons

Black pox

Helminthosporium papulosum Berg.

Black root rot

Xylaria mali Fromme

X. polymorpha (Pers.:Fr.) Grev.

Black rot, frogeye leafspot and canker

Botryosphaeria obtusa (Schwein.) Shoemaker

    Sphaeropsis malorum Berk. [anamorph]

Blister canker = nailhead canker

Biscogniauxia marginata (Fr.) Pouzar

= Nummularia discreta (Schwein.) Tul. & C. Tul.

Blue mold

Penicillium spp.

P. expansum Link

Brooks fruit spot

Mycosphaerella pomi (Pass.) Lindau

    Cylindrosporium pomi C. Brooks [anamorph]

Brown rot blossom blight and spur infection*

Monilinia laxa (Aderhold & Ruhland) Honey

Calyx-end rot

Sclerotinia sclerotiorum (Lib.) de Bary

Clitocybe root rot

Armillaria tabescens (Scop.) Dennis et al.

= Clitocybe tabescens (Scop.) Bres.

Diaporthe canker*

Diaporthe tanakae Kobayashi & Sakuma (Japan)

    Phomopsis tanakae Kobayashi & Sakuma [anamorph]

Diplodia canker

Botryosphaeria stevensii Shoemaker

= Physalospora malorum Shear et al.

    Diplodia mutila (Fr.: Fr.) Mont. [anamorph]

European brown rot

Monilinia fructigena Honey in Whetzel

    Monilia fructigena Pers.:Fr. [anamorph]

Monilinia laxa (Aderhold & Ruhland) Honey

Fisheye rot

Butlerelfia eustacei Weresub & Illman

= Corticium centrifugum (Lév.) Bres.

Flyspeck

Schizothyrium pomi (Mont.:Fr.) Arx

    Zygophiala jamaicensis E. Mason [anamorph]

Fruit blotch, leaf spot and twig canker

Phyllosticta solitaria Ellis & Everh.

Glomerella leaf spot

Glomerella cingulata (Stoneman) Spauld. & H. Schrenk

    Colletotrichum gloeosporioides (Penz.) Penz. & Sacc.

    in Penz. [anamorph]

Gray mold rot = dry eye rot, blossom-end rot

Botrytis cinerea Pers.Fr.

    Botryotinia fuckeliana (de Bary) Whetzel [teleomorph]

Leptosphaeria canker and fruit rot

Diapleella coniothyrium (Fuckel) Barr

= Leptosphaeria coniothyrium (Fuckel) Sacc.

    Coniothyrium fuckelii Sacc. [anamorph]

Leucostoma canker and dieback

Leucostoma cincta (Fr.:Fr.) Hohn.

    Cytospora cincta Sacc. [anamorph]

Valsa auerswaldii Nitschke

= Leucostoma auerswaldii (Nitschke) Hohn.

    Cytospora personata Fr. [anamorph]

Marssonina blotch*

Diplocarpon mali Harada & Sawamura (Japan, Canada, India, Korea, Rumania)

    Marssonina coronaria (Ellis & J. J. Davis)

    J. J. Davis [anamorph]

Moldy core and core rot

Alternaria spp.

Cladosporium spp.

Coniothyrium sp.

Epicoccum spp.

Pleospora herbarum (Pers.) Rabenh.

Stemphylium spp.

Ulocladium spp.

wet core rot, mainly Penicillium spp.

Monilia leaf blight*

Monilinia mali (Takahashi) Whetzel (Japan, China, former Soviet Union)

    Monilia sp. [anamorph]

Monochaetia twig canker

Seiridium unicorne (Cooke & Ellis) Sutton

= Monochaetia mali (Ellis & Everh.) Sacc.

    Lepteutypa cupressi (Nattras et al.) H. J. Swart
    [teleomorph]

Mucor rot

Mucor spp.

M. piriformis E. Fischer

Nectria canker

Nectria galligena Bres. in Strass.

    Cylindrocarpon heteronemum (Berk. & Broome)

    Wollenweb. [anamorph]

Nectria twig blight = coral spot

Nectria cinnabarina (Tode:Fr.) Fr.

    Tubercularia vulgaris Tode:Fr. [anamorph]

Peniophora root canker*

Peniophora sacrata G. H. Cunn.

Perennial canker

Neofabrae perennans Kienholz

    Cryptosporiopsis perennans (Zeller & Childs)

    Wollenweb. [anamorph]

Phomopsis canker, fruit decay and rough bark

Phomopsis mali Roberts

    Diaporthe perniciosa Em. Marchal [teleomorph]

Phymatotrichum root rot = cotton root rot

Phymatotrichopsis omnivora (Duggar) Hennebert

= Phymatotrichum omnivorum Duggar

Phytophthora crown, collar and root rot = sprinkler rot

Phytophthora spp.

P. cactorum (Lebert & Cohn) J. Schröt.

P. cambivora (Petr.) Buisman

P. cryptogea Pethybr. & Lafferty

P. megasperma Drechs.

P. syringae (Kleb.) Kleb.

Phytophthora fruit rot

Phytophthora cactorum (Lebert & Cohn) J. Schrot.

P. syringae (Kleb.) Kleb.

Pink mold rot

Trichothecium roseum (Pers.:Fr.) Link

= Cephalothecium roseum Corda

Powdery mildew

Podosphaera leucotricha (Ellis & Everh.) E. S. Salmon

Rosellinia root rot = Dematophora root rot

Rosellinia necatrix Prill.

    Dematophora necatrix R. Hartig [anamorph]

Rusts

    American hawthorne rust

Gymnosporangium globosum (Farl.) Farl.

    Cedar apple rust

Gymnosporangium juniperi-virginianae Schwein

    Japanese apple rust*

Gymnosporangium yamadae Miyabe ex Yamada (Asia)

    Pacific Coast pear rust

Gymnosporangium libocedri (C. Henn.) F. Kern

    Quince rust

Gymnosporangium clavipes (Cooke & Peck) Cooke & Peck in Peck

Side rot

Phialophora malorum (M. N. Kidd & A. Beaumont) McColloch

Silver leaf

Chondrostereum purpureum (Pers.:Fr.) Pouzar

Sooty blotch complex

Peltaster fructicola (Johnson, Sutton, Hodges)

Geastrumia polystigmatis Batista & M. L. Farr

Leptodontium elatius (G. Mangenot) De Hoog

Gloeodes pomigena (Schwein.) Colby

Southern blight

Sclerotium rolfsii Sacc.

    Athelia rolfsii (Curzi) Tu & Kimbrough [teleomorph]

Thread blight = Hypochnus leaf blight

Corticium stevensii Burt

= Pellicularia koleroga Cooke

= Hypochnus ochroleucus Noack

Valsa canker*

Valsa ceratosperma (Tode:Fr.) Maire (Japan, China, Korea)

    Cytospora sacculus (Schwein.) Gvritischvili [anamorph]

Violet root rot*

Helicobasidium mompa Tanaka (Japan, China, Korea)

White root rot

Scytinostroma galactinum (Fr.) Donk

= Corticium galactinum (Fr.) Burt

White rot

Botryosphaeria dothidea (Moug.) Ces. & De Not.

    Fusicoccum aesculi Corda [anamorph]

X-spot = Nigrospora spot

Nigrospora oryzae (Berk. & Broome) Petch

Zonate leaf spot*

Cristulariella moricola (Hino) Redhead (Japan)

    Grovesinia pyramidalis M. Cline et al. [teleomorph]

NEMATODES, PARASITIC

Dagger nematode

Xiphinema americanum Cobb

X. rivesi Dalmasso

X. vuittenezi Luc et al.

Lesion nematode

Pratylenchus spp.

P. penetrans (Cobb) Filipjev & Schuurmans-Stekhoven

Pin nematode

Paratylenchus spp.

Ring nematode

Criconemella spp.

Root-knot nematode

Meloidogyne spp.

VIRAL DISEASES

Apple chlorotic leafspot

genus Trichovirus, Apple chlorotic leafspot virus (ACLSV)

Apple dwarf (Malus platycarpa)

Apple stem pitting virus (ASPV) (? not US/CAN)

Apple flat apple

genus Nepovirus, Cherry rasp leaf virus (CRLV)

Apple mosaic

genus Ilarvirus, Apple mosaic virus (ApMV)

genus Ilarvirus, Tulare apple mosaic virus (TAMV)

Apple stem grooving = Apple decline of Virginia crab

genus Capillovirus, Apple stem grooving virus (ASGV)

Apple stem pitting = apple Spy 227 epinasty and decline

Apple stem pitting virus (ASPV)

Apple union necrosis and decline

genus Nepovirus, Tomato ringspot virus (ToRSV)

VIROID DISEASES

Apple blister bark (‘Delicious’)

Apple fruit crinkle viroid (AFCVd)

Apple dimple fruit

Apple scar skin viroid (ASSVd)

Apple fruit crinkle*

Apple fruit crinkle viroid (AFCVd) (Japan)

Apple scar skin = apple dapple, apple sabi-ka, apple bumpy fruit

Apple scar skin viroid (ASSVd)

SUSPECTED VIRAL- AND VIROID-LIKE DISEASES (graft-transmissible pathogens [GTP])

Dead spur

GTP, unidentified

False sting

GTP, virus suspected

Green crinkle

GTP, virus suspected

Rough skin

GTP, virus suspected

Star crack

GTP, virus suspected

PHYTOPLASMAL and SPIROPLASMAL DISEASES

Apple chat fruit

Phytoplasma suspected

Apple decline

Phytoplasma suspected

Apple proliferation

Phytoplasma

Rubbery wood

Phytoplasma suspected

MISCELLANEOUS DISEASES and DISORDERS

Bitter pit

Localized calcium deficiency

Blossom blast

Boron deficiency

Burrknot

Genetically predisposed rootstock

Fruit cracking

Genetic

Fruit russet

Frost, sprays, etc.

Green mottle

Unidentified

Hollow apple

High temperature

Internal bark necrosis = measles

Low pH and mineral nutrient imbalance

Internal browning

Boron and calcium deficiencies, etc.

Jonathan spot

Reduced by controlled atmosphere storage

Narrow leaf

Genetic

Necrotic leaf blotch of ‘Golden Delicious’

Rapid synthesis of gibberellins triggered by environmental factors

Storage scald

Injury to fruit surfaces by naturally occurring gases produced by the fruit

Sunburn

Sun injury to fruit

Sunscald

Freezing of bark following high temperatures in winter

Water core

Sorbitol accumulation

*Not known to occur naturally on apple in the United States of America.