Diseases of Geranium (Pelargonium)

Pelargonium × domesticum Bailey
     (regal geranium or Lady Washington or
     Martha Washington geranium; interspecific hybrids)
Pelargonium × hortorum Bailey
     (florists' or zonal geranium; interspecific hybrids)
Pelargonium graveolens L'Her. ex Aiton
     (scented geranium)
Pelargonium peltatum (L.) L'Her. ex Aiton
     (ivy geranium)

Gary W. Moorman, primary collator (last update 10/1/98)

BACTERIAL DISEASES

Bacterial blight: Xanthomonas campestris pv. pelargonii (Brown) Dye
Bacterial fasciation: Rhodococcus fascians (Tilford) Goodfellow; (= Corynebacterium fascians (Tilford) Dows.)
Bacterial leaf spot: Acidovorax sp.; Pseudomonas cichorii (Swingle) Stapp; Pseudomonas syringae van Hall
Crown gall: Agrobacterium tumefaciens (Smith & Townsend) Conn
Southern wilt: Pseudomonas solanacearum E. F. Sm.

FUNGAL DISEASES

Armillaria root rot: Armillaria mellea (Vahl.: Fr.) P. Kumm.
Black root rot: Thielaviopsis basicola (Berk. & Broome) Ferraris
Blackleg (cutting rot): Pythium sp.
Botryosphaeria stem rot: Botryosphaeria ribis Gross. & Duggar
Botrytis blight: Botrytis cinerea Pers. ex Fr.
Cottony stem rot: Sclerotinia sclerotiorum (Lib.) deBary
Damping-off: Pythium sp.; Rhizoctonia sp.
Downy mildew: Peronospora conglomerata Fuckel
Fusarium cutting rot: Fusarium sp.
Glomerella stem rot: Glomerella cingulata (Stoneman) Spauld. & H. Schrenk
Leaf mold: Aspergillus fischerianus R. A. Samson & W. Gams; Diaporthe rudis (Fr.:Fr.) Nitschke
(= D. meduseae Nitschke); Botryosporium pulchrum Corda
Leaf spot: Alternaria alternata (Fr.:Fr.) Keissler
(= Alternaria tenuis Neergaard); Cercospora brunkii Ell. & Gall.; Bipolaris setariae (Sawada) Shoemaker
(teleomorph: Cochliobolus setariae (Ito & Kuribayashi)
Drechs. ex Dastur.); Bipolaris maydis (Nisikado & Miyake) Shoemaker
(teleomorph: Cochliobolus heterostrophus (Drechs.)
Drechs.; Ascochyta sp.; Discohainesia oenotherae (Cooke. & Ellis) Nannf.; Pleosphaerulina sp.; Colletotrichum gloeosporiodes (Penz.) Penz. & Sacc.
(teleomorph: Glomerella cingulata (Stoneman) Spauld. &
H. Schrenk); Phyllosticta sp.; Cylindrocladium scoparium Morg.
(teleomorph: Calonectria kyotensis Terashita)
Phytophthora root rot: Phytophthora sp.
Powdery mildew: Erysiphe communis (Wallr.) Link
Pythium root rot: Pythium sp.
Rhizoctonia root and crown rot: Rhizoctonia solani Kühn (teleomorph: Thanatephorus cucumeris (A. B. Frank) Donk)
Rust: Puccinia pelargonii-zonalis Doidge
Verticillium wilt: Verticillium albo-atrum Reinke & Berthier; Verticillium dahliae Kleb.

VIRAL DISEASES

Leaf cupping and curling: Beet curly top geminivirus
Mosaic: Arabis mosaic virus; Cucumber mosaic virus; Tobacco mosaic virus; Impatiens necrotic spot virus; Tobacco rattle virus
Pelargonium flower break: Pelargonium flower break virus
Pelargonium line pattern: Pelargonium line pattern virus
Pelargonium ring pattern: Pelargonium ring pattern virus
Pelargonium ringspot: Tomato ringspot virus; Tobacco ringspot virus
Pelargonium zonate spot: Pelargonium zonate spot virus
Vein clearing: Pelargonium vein clearing virus

NEMATODES, PARASITIC

Foliar nematode: Aphelenchoides coffeae Zimmerman; Aphelenchoides fragariae (Ritzema Bos) Christie
Nematodes: Pratylenchus pratensis Filipjev; Tylenchorhynchus dubius Cobb; Xiphinema americanum Cobb
Root knot: Meloidogyne arenaria (Neal) Chitwood; Meloidogyne hapla Chitwood; Meloidogyne incognita (Kofold & White) Chitwood

MISCELLANEOUS DISEASES AND DISORDERS

Edema (Oedema): Moisture imbalance in plants when soil is warm and wet while the air is cool and wet
Leaf bleaching: Heat stress
Yellow net vein: Cause unknown