Host Plants - Westcott's Plant Disease - page 614

R OT , Fruit. Alternaria mali,IN;Botrytis
cinerea, occasional; Cephalothecium
roseum, pink mold, occasional; Penicillium
expansum, cosmopolitan; Phoma cydoniae,
pale rot, IL, MI; P. mali, IN.
R UST . Gymnosporangium clavariiforme (0, I),
leaves, fruit, stems, CT, ME, NH; III on
juniper; G. clavipes (0, I), orange rust, quince
rust, on fruit, stems; III on juniper; G. gracile
(0, I); III on juniper; G. libocedri (0, I), fruit,
stems, OR; III on incense-cedar; G. nelsonii
(0, I), leaves, stems, AZ, CO; III on juniper;
G. nidus-avis (0, I), leaves, fruit, stems, CT,
NY; III on juniper.
S CAB . Venturia pirina, CT.
S POT A NTHRACNOSE . Elsino¨ piri, WA.
Quinces are subject to fire blight; infected
branches should be cut out with the usual pre-
cautions. For leaf blight, spray when blossoms
show pink, again when last of the petals are
falling, and perhaps twice more at 2-week inter-
vals. Brown rot is not very important on quince.
To prevent rust, remove nearby susceptible juni-
pers or spray them in spring as spore horns are
developing on galls. See under

R UST , Quince. Gymnosporangium clavipes (0, I),
on stems; CT, NJ; III on juniper; G. libocedri
(0, I), on leaves; III on incense-cedar.

Rabbitbrush (Chrysothamnus)

L EAF S POT . Phloeospora bigeloviae, CA.
P OWDERY M ILDEW . Golovinomyces
cichoracearum, CA, MT, UT, WY; Erysiphe
polygoni var. sepulta, CO, MT, UT, WY.
R UST . Puccinia dioicae (0, I), NM and CA;
P. grindeliae (III), MT to NM, CA; P. stipae
(0, I), MT to NM, CA; II, III on grasses.
S MUT , Inflorescence. Thecaphora pilulaeformis,
AZ.

Radish (Raphanus)

B ACTERIAL Black Rot. Xanthomonas
campestris, IN, IA, MI, NJ, NY, OH, PA, TX.
B ACTERIAL , Phytoplasma. California Aster Yel-
lows, CA; Virescence, ID, WA.
B ACTERIAL Soft Rot. Erwinia carotovora,
cosmopolitan.
B ACTERIAL Spot. Xanthomonas vesicatoria pv.
raphani, IN; Xanthomonas campestris pv.
armoraciae,OH.
B LOTCH ; Black Pod. Alternaria raphani, CA,
MI, MN, NJ, OH, PA.
C LUB R OOT . Plasmodiophora brassicae, occa-
sional in North, MA to NJ, MN, WA.
D AMPING -O FF . Pythium debaryanum, MA, MN,
NJ, WY; Rhizoctonia solani, cosmopolitan.
D OWNY M ILDEW . Peronospora parasitica, north-
eastern and central states to MS, CA, TX.
L EAF S POT . Alternaria brassicae, gray leaf spot,
CA; A. oleracea, black leaf spot, CT, NJ;
Cercospora cruciferarum, AL,

RUSTS .

▶

Quince, Flowering, Japanese, Chinese
(Chaenomeles)

B ACTERIAL Crown Gall. Agrobacterium

tumefaciens, occasional.
B ACTERIAL Fire Blight. Erwinia amylovora,
occasional.
B LIGHT , Leaf. Fabraea macula, AL, CT, NJ, NY.
C ANKER , Felt Fungus. Septobasidium burtii,

MS; S. mariani, NC.
C ANKER , Twig Blight. Botryosphaeria ribis, AL,
TX; Phoma sp., MD, TX; Physalospora
obtusa, TX, eastern states.
F RUIT S POT . Mycosphaerella pomi, IL, MD, also
leaf blotch.
L EAF S POT . Cercospora cydoniae, AL, GA.
N EMATODE , Root Knot. Meloidogyne sp.
R OT , Brown. Monilinia fructicola, leaf
blight, MI; M. laxa, also blossom and twig
blight, CA.

IL, MO,

TX; C. atrogrisea, NJ.
N EMATODE , Leaf and Stem. Ditylenchus dipsaci,
NY.
N EMATODE , Root Knot. Meloidogyne arenaria;
M. javanica, AL, MS, OR, PA, TX.
N ONPARASITIC . Air Pollution.NO 2 ,O 3 ,SO 2 , NC.
P OSTHARVEST , Black Patch. Alternaria raphani,
St. Catharines, Canada.