Host Plants - Westcott's Plant Disease - page 578

V IRUS . Oak Ringspot, AR.
W ILT , Dieback. Fusarium oxysporum or
F. solani, VA; also canker; Phytophthora
europa (also yellowing and dieback), North
Central U.S., MN, OH, PA, WV, WI.
W ILT , Oak. Ceratocystis fagacearum ( Chalara
quercina ), AR, FL, IL, IN, IA, KS, KY, MD,
MI, MN, MO, NE, NY, NC, OH, OK, PA, SC,
TN, VA, WV, WI.
W ITCHES 'B ROOM . Articularia quercina var.
minor. AZ, NM, UT.
Oak wilt is our most serious disease with red
and black oaks often dying the first season symp-
toms appear. Anthracnose is general, most
severe on white oak, defoliating in wet seasons.
Leaf blister, important in the South, can be
prevented by a single dormant spray. Powdery
mildew, due to Sphaerotheca lanestris ,isimpor-
tant in California, where it produces witches'
brooms on live oaks. The honey mushroom,
Armillaria mellea , sometimes called the oak
fungus, causes “shoestring” root rot. Strumella
canker is frequent in forest trees, sometimes
found in ornamentals.

L EAF S POT . Alternaria tenuis, secondary, NJ;
Cercospora oenotherae, AL, KS, TX, WV;
C. oenotherae-sinutae, AL, NC; Pezizella
oenotherae, GA, MD, NC, SD, VA;
Pestalotia oenotherae, OH, OK; Septoria
oenotherae, ME to FL, CA, NM, OK, SD, UT.
P OWDERY M ILDEW . Erysiphe polygoni, general.
R OT , Root. Phymatotrichum omnivorum, TX;
Rhizoctonia solani, TX; Sclerotinia minor,
NC.
R UST . Aecidium anograe (0, I), NE; Puccinia
aristidae (0, I), AZ, NV; II, III on grasses;
P. dioicae (0, I), ME to AL, CA, CO, ND,
TX; II, III on Carex ; P. oenotherae (0, I, II,
III), CO, CA to MT, WA; Uromyces

plumbarius (0, I, II, III), general.
V IRUS . Mosaic. Unidentified, PA.

Ohia (Metrosideros spp.); also Eugenia,
Syzgium and Psidium spp. in
Myrtaceae Family

R UST . Puccinia psidii, HI.

Oat Okra (Hibiscus esculentus)

V IRUS . Oat Blue Dwarf, upper Midwest, United
States.

A NTHRACNOSE . Colletotrichum gloeosporioides,
pod spot, FL, PA; C. hibisci, dieback, TX.
B LIGHT ,

Blossoms. Choanephora

cucurbitarum, FL, GA, TX.
L EAF S POT . Ascochyta abelmoschi, GA, MD, NJ,
NY, pod spot; Alternaria sp., secondary, FL,
OH, PA, SC, UT; Cercospora abelmoschi
( C. hibisci ), NC to FL, TX; C. malayensis,
VA to FL, OK, TX; Corynespora cassiicola;
Phyllosticta hibiscina, AL, IL, NJ, NC, OK.
N EMATODE , Root Knot. Meloidogyne incognita,
general.
P OWDERY M ILDEW . Golovinomyces
cichoracearum, CT, NJ, NC, PA.
R OT , Charcoal. Macrophomina phaseoli, TX.
R OT ,Pod.Botrytis sp., NY.
R OT , Root. Phymatotrichum omnivorum, TX;
Rhizoctonia solani, damping-off, AL, FL;
Thielaviopsis basicola, NJ.

Ocotillo, Coach-Whip, Candlewood
(Fouquieria)

R OT , Root. Phymatotrichum omnivorum, TX.
R UST . Aecidium cannonii (0, I), AZ.

Oenothera (Evening-Primrose)

B LIGHT , Gray Mold. Botrytis cinerea, AK.
D ODDER . Cuscuta arvensis, OK.
D OWNY M ILDEW . Peronospora arthuri,MAto
MS, KS, MT, NE, OK, SD.
G ALL , Leaf. Synchytrium fulgens, AL, KS, LA,
MS, NC, OK, TX to CA.