Host Plants - Westcott's Plant Disease - page 540

R OT , Root. Phymatotrichum omnivorum, TX;
Armillaria mellea, CA.
R OT , Stem. Rhizoctonia solani, MD; wound,
Polyporus versicolor, CT, IA, MD.
R UST . Pucciniastrum hydrangeae (II, III), PA to
AR, IL; 0, I on hemlock.
V IRUS . Hydrangea Ring Spot; Tomato Spotted
Wilt; Hydrangea Latent; Chlorotic Mottle,
MN, NY.

Hyssop (Hyssopus)

N EMATODE , Root Knot. Meloidogyne sp., MI.

Ice Plant (Carpobrotus)

R OT , Root. Pythium aphanidermatum, CA;
Phytophthora cryptogea, CA.
W ILT . Verticillium dahliae, CA; Phomopsis sp.,
CA.

Hydrilla (Aquatic)

D YING S HOOTS . Plectosporium tabacinum,FL,
Bioassay indicated that Botrytis sp.,
Cephalosporium sp., Curvularia sp., Fusar-
ium culmorum, F. moniliforme, d
Phytophthora sp. were pathogenic to hydrilla.
Notes: Hydrilla is a submerged aquatic weed. It
is an exotic, invasive species that is a threat to
fresh water sources in the USA.

Impatiens (Garden Balsam, Sultan)

B ACTERIAL B LIGHT L EAF . Pseudomonas syringae,
CA.
B ACTERIAL F ASCIATION . Clavibacter fascians,CA.
B ACTERIAL Wilt. Pseudomonas solanacearum,
WI.
D AMPING -O FF . Pythium sp., WA; Rhizoctonia
solani, FL.
D OWNY M ILDEW . Bremiella sphaerosperma, IN,
MN, MS, MT, WI, Manitoba, Quebec,
Canada;

Hydrophyllum (Waterleaf)

D OWNY M ILDEW . Peronospora hydrophylli, IL,
IA, MD, NY, WA, WI.
L EAF S POT . Ascochyta hydrophylli, WA;
Gloeosporium hydrophylli, NH; Ramularia
hydrophylli, WA; Septocylindrium
hydrophylli, NY; Septoria hydrophylli, NY.
P OWDERY M ILDEW . Golovinomyces
cichoracearum, occasional; Erysiphe
polygoni, ID, WA; Sphaerotheca macularis,
ND, OH, SD.
R OT , Leaf and Stem. Ceratobasidium anceps,
NY, WI.
R UST . Puccinia hydrophylli (III), CA, CO, NY to
NE, ND, UT; P. recondita (0, I), MT, wide-
spread; II, III on grasses.

Plasmopara obducens, CA, IL,

MA, NY.
G ALL , Leaf. Synchytrium impatientis, LA.
L EAF S POT . Cercospora fukushiana, FL, KS;
Septoria noli-tangeris, OH; Phyllosticta
sp., NJ.
N EMATODE , Lesion. Pratylenchus penetrans.
N EMATODE , Root Knot. Meloidogyne sp.
R OT , Crown. Pythium ultimum and Rhizocto-
nia solani.
R OT , Mushroom Root. Armillaria mellea, CA.
R OT , Stem. Sclerotium rolfsii; Myrothecium
roridum.
V IRUS . Cucumber Mosaic, SC; Impatiens
Latent, MN; Impatiens Necrotic Spot,
NC; Tomato Spotted Wilt, FL, GA, NC,
OK; TurnipMosaic, NY; Tobacco Ringspot,
IA, MN.
W ILT .

Hymenopappus

D OWNY M ILDEW . Plasmopara halstedii,OK.
R OT , Root. Phymatotrichum omnivorum,TX.
R UST . Puccinia grindeliae (0, III), OK.

Verticillium albo-atrum, NY;

Verticillium dahliae, OH.