Host Plants - Westcott's Plant Disease - page 599

W ILT . Verticillium albo-atrum, MN, NY.
When gardeners talk about “rust” on phlox, they
usually mean the physiological blight, for true rusts
are uncommon on perennial summer phlox. Pow-
dery mildew is general and especially disfiguring
when plants are shaded or crowded with little air
circulation. Sulfur dust is still good.

D OWNY M ILDEW . Plasmopara cephalophora,
WI.
L EAF S POT . Mycosphaerella physostegiae, GA,
VA; Septoria physostegiae, IL, WI.
R OT , Stem. Sclerotinia sclerotiorum, ME.
R UST . Puccinia physostegiae (III), IN, MT, NH,
NY.
V IRUS . Tomato Spotted Wilt, PA.

Phoenix-Tree (Firmiana simplex)

Pick-a-Back (Tolmiea)

B LIGHT , Web. Rhizoctonia microsclerotia, FL.
C ANKER ; Coral Spot. Nectria cinnabarina, OK.
R OT , Root. Phymatotrichum omnivorum, TX.

P OWDERY M ILDEW . Sphaerotheca sp., OR.
V IRUS . Tomato Spotted Wilt, PA.

Pieris (Mountain, Japanese
Andromeda) Photinia (Christmasberry, Toyon and

Oriental Species)

B LIGHT , Phytophthora ramorum, OR;

A NTHRACNOSE . Gloeosporium sp., MS.
B ACTERIAL Fire Blight. Erwinia amylovora, CA,
NJ.
B LIGHT , Leaf. Fabraea maculata, CA, LA.
D IEBACK . Cytospora sp.
L EAF S POT . Cercospora sp., GA; C. heteromeles,
CA, TX; C. photiniae-serrulata; C.
eriobotryae; Lophodermium heteromeles,
CA; Phyllosticta heteromeles,CA,TX;
Pestalotia sp., NJ; Septoria photiniae,CA,PA.
P OWDERY M ILDEW . Podosphaera leucotricha,
CA; Sphaerotheca pannosa, OR.
R OT , Crown. Phytophthora cactorum, CA.
R OT , Root. Clitocybe tabescens, FL;
Phymatotrichum omnivorum, TX;
Phytophthora lateralis, NC; P. syringae,
NC.
R UST . Gymnosporangium japonicum (0, I), III
on juniper; G. clavipes,MA.
S CAB . Photinia photinicola ( Spilocaea
eriobotryae ), on leaves, berries, CA.

P. tropicalis, VA.
B LIGHT , Twig. Cytospora sp., OR.
D IEBACK . Phytophthora sp., PA; Phytophthora
cambivora, NC.
L EAF S POT . Pestalotia sp., CT, NJ; Phyllosticta
andromedae, NJ; P. maxima, CT, NJ;
Alternaria tenuis, RI.
L EAF S POT , Tar. Rhytisma andromedae, FL, GA.
R OT , Root. Armillaria mellea, NJ.

Pigeon Pea (Cajanus)

P HYTOPLASMA , Witches' Broom. FL.
V IRUS . Pigeon Pea Golden Mosaic.

Pine (Pinus)

B LACK M ILDEW . Lembosia acicola, CA.
B LIGHT , Diplodia. Diplodia pinea, AL, LA, MS.
B LIGHT , Brown Felt. Herpotrichia nigra, North-
west, on snow-buried foliage at high altitudes;
Neopeckia coulteri, CA, MT.
B LIGHT , Brown Spot Needle. Systremma
( Scirrhia ) acicola, on hard pines in South, on
Red pine, WI.
B LIGHT , Foliage. Rhizoctonia solani, VA.

Physostegia (False Dragonhead)

B LIGHT ; Southern Crown Rot. Sclerotium rolfsii,
VA to OK, CT, KS, NJ, NY, WI.