Host Plants - Westcott's Plant Disease - page 670

P OWDERY M ILDEW . Phyllactinia corylea, MI, WI;
Podosphaera biuncinata, New England to IL
and southward.
R OT , Wood. Fomes scutellatus, widespread;
Polyporus spp.

Wyethia

L EAF S POT . Didymaria conferta, OR, UT;
Marssonina wyethiae, CA, WA; Septoria
wyethiae, CA, UT.
N EMATODE ,

Leaf Gall. Tylenchus

Wolfberry (Symphoricarpos
occidentalis)

balsamophilus, UT.
R UST . Puccinia balsamorhizae (0, I, II, III), AZ,
CA, CO, UT.

B LACK K NOT . Dibotryon symphoricarpi, twig
canker, ND.
L EAF S POT . Cercospora symphoricarpi, MT, ND,
WA; Septoria symphoricarpi,IA,MT,ND,
WA.
P OWDERY M ILDEW . Microsphaera

Xanthosoma

R OT , Root. Armillaria mellea, CA; Fusarium
solani, powdery gray rot, FL.

diffusa,

general.
R OT , Collar. Fomes ribis, KS, ND.
R UST . Puccinia crandallii (0, I), CO, MT, ND,
WY; II, III on grasses; P. symphoricarpi,MT.

Xerophyllum (Turkeybeard)

R UST . Puccinia atropuncta (II, III), MS.

Wood-Betony, Lousewort (Pedicularis)

Yam, Cinnamon-Vine (Dioscorea)

G ALL , Leaf. Synchytrium aureum, WI.
L EAF S POT . Ramularia obducens, CA; Septoria
cylindrospora, WI.
P OWDERY M ILDEW . Sphaerotheca macularis,
CA, CO, MD, MI, MN, WY, WI.
R UST . Cronartium coleosporioides (II, III), CA,
ID, MT, NM, WA; Puccinia clintonii (III),
CO, ID, ME, MI, NM, NY, OR, WA, WI, WY;
P. rufescens (I, III), CA, CO, NV.

L EAF S POT . Cercospora dioscoreae, IL, IA, MD,
MI, PA, WI; Colletotrichum dioscoreae, IL;
Phyllosticta dioscoreae, SC, VA, WV;
Ramularia dioscoreae, WI.
N EMATODE , Root Knot. Meloidogyne sp., NC.
R OT , Root. Phymatotrichum omnivorum,
TX.

Yarrow (Achillea)

Wood Rose (Rosa gymnocarpa,
R. californica)

B ACTERIAL Crown Gall. Agrobacterium

tumefaciens, IN.
D ODDER . Cuscuta sp., NH.
N EMATODE , Root Knot. Meloidogyne sp., OR.
P OWDERY M ILDEW . Golovinomyces
cichoracearum, AK, MO, MT, PA, SD, VT,
WI.
R OT , Root. Phymatotrichum omnivorum, TX;
Rhizoctonia solani, general.
R UST . Puccinia millefolii (III), CA, CO, ID, MT,
NM, OR, UT, WA, WY.

L EAF S POT , Lesions. Phytophthora

gymnocarpa, CA.

Woodrush (Luzula)

R UST . Puccinia obscura (II, III), ME to KS, ID,
OR, WA, WI.
S MUT . Inflorescence. Cintractia luzulae,IN.