Host Plants - Westcott's Plant Disease - page 476

B LIGHT , Southern. Sclerotium rolfsii, FL, VA.
D ODDER . Cuscuta sp., MI, NJ, NY, WA, WV;
C. arvensis and C. indecora, TX.
L EAF S POT . Alternaria sp., OK, TX;
Cercospora chrysanthemi, AL, LA, MD,
PA, TX; Cylindrosporium chrysanthemi,
MA to AL and KS; Phyllosticta
chrysanthemi, FL, MA, MS, VA; Septoria
chrysanthemella

Christmas Berry (Heteromeles
arbutifolia)

B LIGHT , Sudden Oak Death. Phytophthora
ramorum, CA.
R UST . Gymnosporium exiguum, CA.

( S.

chrysanthemi )

and

Christmas Cactus (Zygocactus
truncatus)

S. obesa, general.
N EMATODE , Leaf. Aphelenchoides ritzemabosi,
widespread.
N EMATODE , Lesion. Pratylenchus pratensis, NJ,
TX.
N EMATODE , Root Knot. Meloidogyne spp.
N ONPARASITIC . Crackneck. In greenhouses, prob-
ably overwatering and insufficient ventilation.
Air Pollution Injury.
Yellow Strapleaf. Amino acid imbalance.
P ETAL S POT . Bipolaris

R OT , Basal Stem. Fusarium oxysporum,MA.
R OT , Root. Phytophthora parasitica, FL.
V IRUS . Zygocactus Montana X, MT.

Christmas Rose (Helleborus niger)

( Helminthosporium ) B LIGHT , Flower Spot. Botrytis cinerea, NJ;

Gloeosporium sp., NJ.
L EAF S POT , Black. Coniothyrium hellebori, MD,
NY, OR.
R OT , Stem. Sclerotium delphinii ( S. rolfsii ), NY.

setariae, FL.
P OWDERY

M ILDEW . Golovinomyces

cichoracearum, general.
R OT , Charcoal Stem. Macrophomina phaseoli,
OK.
R OT , Flower. Fusarium tricinctum f. sp. poae,
LA, NJ.
R OT , Root. Fusarium sp.; Rhizoctonia solani,
general; Pythium sp.; Phymatotrichum
omnivorum, AZ, TX.
R OT , Stem. Fusarium solani.
R OT , Stem; Drop. Sclerotinia sclerotiorum, AZ,
LA, MI, VA.
R UST . Puccinia taneceti (II), general.
V IROID . Chrysanthemum Stunt, serious; Chry-
santhemum Chlororic Mottle, FL, NY,
widespread.
V IRUS . Chrysanthemum Flower Distortion;
Chrysanthemum Mosaic; Chrysanthemum
Ring Spot; Chrysanthemum Rosette; Impa-
tiens Necrotic Spot, GA, NC; Tomato
Aspermy; Tomato Spotted Wilt.
W HITE R UST . Puccinia horiana (III, IV), CA, FL,
NJ, OR, PA.
W ILT . Fusarium oxysporum f. sp. callistephi;
F. oxysporum f. sp. tracheiphilum, SC;
F. oxysporum f. sp. chrysanthemi, FL, SC,
widespread; Verticillium albo-atrum.

Chrysanthemum (Dendranthema
grandiflora)

B ACTERIAL , MLO. PhloemNecrosis. MLO, wide-
spread; Aster Yellows.
B ACTERIAL Blight; Wilt. Erwinia chrysanthemi,
serious in greenhouses; E. carotovora, OK;
Pseudomonas cichorii, FL.
B ACTERIAL Crown Gall. Agrobacterium
tumefaciens, CT, FL, NJ, TX.
B ACTERIAL Fasciation. Clavibacter fascians, MI,
NJ, NY, OH.
B LIGHT ,Blossom.Phytophthora nicotianae,AL.
B LIGHT , Gray Mold. Botrytis cinerea,

cosmopolitan.
B LIGHT , Leaf; Blotch. Septoria leucanthemi,
widespread.
B LIGHT , Petal. Itersonilia perplexans, FL, MN.
B LIGHT , Ray. Ascochyta chrysanthemi
( Mycosphaerella ligulicola ), MD to FL, CA,
MS, OH; Ray Speck, Stemphylium
floridanum, FL; Alternaria spp.