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Diseases of Poinsettia
(Euphorbia pulcherrima Willd. ex Klotzsch)

G. W. Simone, primary collator (last update 11/08/00)


Bacterial leaf spot
Curtobacterium flaccumfaciens (Hedges 1922) Collins and
    Jones 1984
= Corynebacterium flaccumfaciens pv. poinsettiae
(Starr & Pirone 1942) Dye & Kemp 1977
Pseudomonas cichorii (Swingle 1925) Stapp 1928
Ps. marginalis (Brown 1918) Stevens 1925
Ps. syringae subsp. syringae van Hall 1902
Xanthomonas campestris pv. poinsettiaecola (Patel et al.
    1951) Dye 1978
Bacterial stem rot
Erwinia carotovora subsp. carotovora (Jones 1901) Bergey
    et al. 1923
Erwinia chrysanthemi Burkholder et al. 1953
Crown gall
Agrobacterium tumefaciens (Smith and Townsend 1907) Conn 1942
Greasy center
Pseudomonas viridiflava (Burkholder 1930) Dowson 1939


Colletotrichum capsici (Syd.) E.J. Butler & Bisby
Colletotrichum dematium (Pers.) Grove
Glomerella cingulata (Stoneman) Spauld. & H. Schrenk
    C. gloeosporioides (Penz.) Penz. & Sacc. in Penz.
Aerial blight
Ceratobasidium ramicola Tu, D.A. Roberts & Kimbrough
    Rhizoctonia ramicola G.F. Weber & D.A. Roberts
Basal stem and crown rot
Sclerotinia sclerotiorum (Lib.) deBary
Basal stem and root rot
Ceratocystis sp.
    Thielaviopsis basicola (Berk. & Broom) Ferraris
    Chalara elegans Nag Raj & Kendrick [synanamorph]
Black rot
Botryodiplodia sp.
Bract, flower and leaf blight
Phytophthora drechsleri Tucker
Bract spot
Corynespora cassiicola (Berk. & M.A. Curtis) C.T. Wei
Crown and stem rot
Fusarium oxysporum Schlechtend.:Fr.
Nectria haematococca Berk. & Broome
    Fusarium solani (Mart.) Sacc. [anamorph]
Cutting rot
Cylindrocladium scoparium Morgan
Lasiodiplodia theobromae (Pat.) Griffon & Maubl.
=Botryosphaeria theobromae Pat.
Gray mold
Botryotinia ricini (Godfrey) Whetzel
    Amphobotrys ricini (Buchwald) Hennebert [anamorph]
=Botrytis ricini
Botryotinia fuckeliana (deBary) Whetzel
    Botrytis cinerea Pers.:Fr. [anamorph]
Leaf necrosis
Cladosporium sp.
Macrophoma sp.
Leaf spot
Alternaria euphorbiicola E. Simmons & Engelhard
Ascochyta sp.
Cercospora pulcherrimae Tharp
Curvularia sp.
Drechslera sp.
Myrothecium roridum Tode:Fr.
Phyllosticta sp.
Syspastospora parasitica (Tul.) P. Cannon & D. Hawksworth
= Melanospora parasitica (Tul.) Tul. & C. Tul.
Stemphylium sp.
Mushroom root rot
Armillaria tabescens (Scop.) Dennis, Orton & Hora
Powdery mildew
Oidium sp.
Erysiphe sp.
Microsphaera euphorbiae Berk. & M.A. Curtis
Root rot
Phytophthora nicotianae Breda de Haan
= P. nicotianae var. parasitica (Dastur) G.M. Waterhouse
Pythium aphanidermatum (Edson) Fitsp.
P. debaryanum Auct. non R. Hesse
P. myriotylum Drechs.
P. perniciosum Serbinow
P. splendens H. Braun
P. ultimum Trow
Root and stem rot
Thanatephorus cucumeris (A.B. Frank) Donk
    Rhizoctonia solani Kühn [anamorph]
Puccinia sp.
Uromyces euphorbiae Cooke & Peck in Peck
= U. proeminens Pass. In Rabenh. var. poinsettiae
(Tranzschel) Arth.
Sphaceloma poinsettiae Jenk. & Ruehle
Stem gall
Nectriella pironii Alfieri & Samuels
    Kutilakesa pironii Alfieri [anamorph]
Stem rot
Botryosphaeria ribis Gross. & Duggar
Diplodia sp.
Leptothyrium sp.
Phoma sp.
Phomopsis sp.


Root knot nematode
Meloidogyne spp.


genus Bigeminivirus, Euphorbia mosaic virus (EuMV)
Poinsettia mosaic virus (possible tymovirus) (PnMV)
Poinsettia (?) alphacryptovirus (PnCV)


Bleaching necrosis
Air pollutant injury from either chlorides (> 0.5 ppm), nitrogen dioxide (> 2-3 ppm) or sulfur dioxide (> 0.5 ppm)
Bract necrosis
Physiological disorder favored by high humidity, heavy watering and high (ammoniacal) fertility rates in the last 4 weeks of production
Nitrogen deficiency producing a general foliar yellowing
Molybdenum deficiency affecting mature young leaves and
    producing upward leaf roll
Sulfur deficiency causing young leaf yellowing
Zinc deficiency producing general yellowing and stunting of
    new leaves
Cyathia drop
Response to low light conditions, dryness and/or high temperatures at the end of the production cycle
Dropping (epinasty)
Ethylene toxicity (< 1 ppm) or low temperature chilling
Interveinal chlorosis
Magnesium deficiency, initiating on older leaves
Manganese deficiency, initiating on young mature leaves
Ammonium toxicity produces V-shaped chlorotic bands
    starting at the leaf tip and accompanied by downward leaf
Latex eruption
High internal turgor pressure associated with certain cultivars, high humidity, high moisture availability, low temperatures and/or mechanical abrasion
Leaf glazing (bronzing)
Peroxyacetyl nitrate (PAN) injury to the lower epidermis
(> 0.2 ppm)
Marginal necrosis
Potassium deficiency
Fluoride toxicity on tips and margins of young leaves and bracts
    (0.4 ppm in water)
Lithium toxicity on older leaves (2 ppm)
Stem splitting
Physiological expression of flower initiation
Ozone injury (> 4 ppm)
Terminal shoot necrosis
Excessive soluble salts (> 800 EC X 102)
White bract
Chilling injury occurring between 0-10°C (32-50°F)