Common Names of Plant Diseases

Diseases of Rhododendron
(Rhododendron spp.)

D. M. Benson, primary collator (last update 2/25/93)

BACTERIAL DISEASE

Crown gall

Agrobacterium tumefaciens (Smith & Townsend) Conn

FUNGAL DISEASES

Armillaria root rot (shoestring root rot)

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

(anamorph: Rhizomorpha subcorticalis Pers.)

Botryosphaeria dieback

Botryosphaeria dothidea (Moug.: Fr.) Ces. & DeNot.

(anamorph: Fusicoccum aesculi Corda)

Botrytis leaf and petal blight

Botrytis cinerea Pers.: Fr.

(teleomorph: Botryotinia fuckeliana (de Bary) Whetzel)

Bud and twig blight

Pycnostysanus azaleae (Peck) E. Mason

= Briosia azaleae (Peck) Dearn.

Cercospora leaf spot

Pseudocercospora handelii (Bubak) Deighton

= Cercospora handelii Bubak

Chrysomyxa leaf rust

Chrysomyxa ledi de Bary var. rhododendri (de Bary) Savile

C. piperiana Sacc. & Trott. ex Cummins

C. roanensis (Arth.) Arth.

Clitocybe root rot (mushroom root rot)

Armillaria tabescens (Scop.) Dennis et al

= Clitocybe tabescens (Scop.) Bres.

Coryneum leaf spot

Seimatosporium rhododendri (Schwein.) Pirozynski &
    Shoemaker

= Coryneum rhododendri Schwein.

Cryptostictis leaf spot

Seimatosporium mariae (G.W. Clinton) Shoemaker

= Cryptostistis mariae (G.W. Clinton ex Peck) Sacc.

Cylindrocarpon canker and wilt

Cylindrocarpon destructans (Zinssmeister) Scholten

= Cylindrocarpon radicicola Wollenweb.

Damping-off, Pythium

Pythium spp.

Damping-off, Rhizoctonia

Rhizoctonia solani Kühn

(teleomorph: Thanatephorus cucumeris (A.B. Frank) Donk)

Exobasidium leaf spot

Exobasidium burtii Zeller

Glomerella canker and dieback

Glomerella cingulata (Stoneman) Spauld. & H. Schrenk

(anamorph: Colletotrichum gloeosporioides (Penz.) Penz. &
    Sacc. in Penz.)

Gray blight

Pestalotia sydowiana Bres.

Leaf and flower gall

Exobasidium vaccinii (Fuckel) Woronin

= Exobasidium azaleae Peck

Lophodermium leaf spot

Lophodermium schweinitzii M. Wilson & N.F. Robertson

Ovulinia petal blight

Ovulinia azaleae Weiss

(anamorph: Ovulitis azaleae Buchwald)

Pestalosphaeria leaf spot

Pestalosphaeria concentrica Barr

(anamorph: Pestalotiopsis guepini (Desmaz.) Steyaert var.
    macrotricha (Kleb.) Sutton)

Pestalotia leaf spot

Pestalotiopsis sydowiana (Bres.) Sutton

= Pestalotia rhododendri Guba non Westend., hom. illeg.

Phymatotrichum root rot (cotton root rot)

Phymatotrichopsis omnivora (Duggar) Hennebert

= Phymatotrichum omnivorum Duggar

Phytophthora dieback

Phytophthora nicotianae Breda de Haan var. parasitica
    (Dastur) G.M. Waterhouse

= P. parasitica Dastur

P. cactorum (Lebert & Cohn) Schrot.

P. cinnamomi Rands

P. citricola Sawada

P. citrophthora (R.E. Sm. & E.H. Sm.) Leonian

P. heveae A. Thompson

P. lateralis Tucker & Milbrath

Phytophthora root rot

Phytophthora cactorum (Lebert & Cohn) J. Schröt.

P. cinnamomi Rands

P. citricola Sawada

Powdery mildew

Microsphaeravaccinii (Schwein.) Cook & Peck

= M. penicullata (Wallr.:Fr.) Lév. var. vaccinii (Schwein.)
    W.B. Cooke

Pucciniastrum leaf rust

Pucciniastrum vaccinii (G. Wint.) Jørst.

Septoria leaf spot

Septoria rhododendri Cooke

Spot anthracnose

Sphaceloma sp.

Stem canker

Cylindrocladium theae (Petch) Subramanian

(teleomorph: Calonectria theae C.A. Loos)

Witches' broom

Exobasidium vaccinii-uliginosi Boud. in Boud. & E. Fisch.

NEMATODES, PARASITIC

Dagger, American

Xiphinema americanum Cobb

Lance

Hoplalaimus galeatus (Cobb) Thorne

Sheath

Hemicycliophora spp.

Spiral

Helicotylenchus erythinae Sher

Stubby-root

Paratrichodorus spp.

Stunt

Tylenchorhynchus claytoni Steiner

PARASITIC HIGHER PLANT

Dodder

Cuscuta gronovii Willd.

VIRUS DISEASE

Necrotic ringspot

Potato virus X group