Host Plants - Westcott's Plant Disease - page 424

N EMATODE , Leaf. Aphelenchoides ritzemabosi;
Lesion, Pratylenchus sp., MD, NJ, OH.
N EMATODE , Root Knot. Meloidogyne arenaria,
general.
N EMATODE , Spiral. Scutellonema brachyurus,
MD.
N ONPARASITIC . Ring Spot, due to wetting foliage
with cold water, general.
Petiole Rot, from touching rim of salt-encrusted
pot.
P OWDERY M ILDEW . Oidium sp., occasional

Ageratum

B LIGHT , Southern. Sclerotium rolfsii, NJ, NC,
probably widespread.
P OWDERY M ILDEW . Golovinomyces

cichoracearum, MD.
R OT , Root. Pythium mamillatum, CA.
R OT , Root and Stem. Rhizoctonia solani, IL, NJ,
NM.
R OT , Stem. Alternaria zinniae, IL.
R UST . Puccinia conoclinii (II, III), GA, MS, NC;
0, I unknown.
V IRUS .Bidens Mottle, FL; Tomato Spotted
Wilt-lettuce serotype, GA.

in

greenhouses.
R OT , Root. Rhizoctonia solani; Fusarium
solani, MD, NY; Cylindrocarpon radicicola,
MD, NY.
R OT , Root and Crown. Pythium ultimum, CA,
probably general; Phytophthora sp.,

Agrimony (Agrimonia) MD, NC.

Bright yellow ring patterns appear if there is
too steep a temperature gradient between leaf and
water. Yellowing may be due to excessive bright
sunlight. Non-flowering may be due to improper
light. Root-knot nematodes as well as mites
causes thickened, blistered leaves.

B LIGHT , Stem. Phoma herbarum, TX.
D OWNY M ILDEW . Peronospora potentillae, IA,
NY, WI.
L EAF S POT . Cercospora sp., IL; Phyllosticta
decidua, NC, WI; Septoria agrimoniae, IL,
IN, IA, MO, NY, NC, TX, WI; S. agrimoniae-
eupatoriae, IA.
P OWDERY M ILDEW . Sphaerotheca macularis,
MA, NE, NC, WI.
R OT ,Root.Phymatotrichum omnivorum,TX.
R UST . Puccinia agrimoniae (II, III), MO;
0, I unknown; Pucciniastrum agrimoniae
(II, III), general ME to FL, NM, ND;
0, I unknown.
V IRUS . Mosaic. Unidentified, NY.

Agapanthus (African-Lily)

B ACTERIAL Leaf Streak (water-soaked).
Xanthomonas axonopodis, FL.
V IRUS . Ornithogalum Mosaic.

Agastache (Giant-Hyssop)

Ailanthus (Tree-of-Heaven)

D OWNY M ILDEW . Peronospora lophanthi, IL, IA,
WI.
L EAF S POT . Ramularia lophanthi, CA, MT;
Septoria lophanthi, IL, MO, OH, WI.
L EAF S POT ; Stem Spot. Ascochyta lophanthi, IL,
IA, WI.
P OWDERY M ILDEW . Sphaerotheca macularis ( S.
humuli ), MO, UT, WA, WI.
R UST . Puccinia hyssopi (III), NY to IA, MO, WI.
V IRUS . Mosaic. Unidentified, IN.
W ILT . Verticillium dahliae, IA.

B LACK M ILDEW . Dimerosporium robiniae, DC.
B LIGHT , Twig. Gibberella baccata
( Fusarium lateritium ), VA; Diplodia
ailanthi, TX; D. natalensis, TX; Phoma
ailanthi, TX.
C ANKER ;D IEBACK . Nectria cinnabarina, KS, NJ,
SC; N. coccinea, occasional; Physalospora
obtusa, KS, MI, NY.
L EAF S POT . Cercospora glandulosa, widespread;
Gloeosporium ailanthi, LA, TX, WV;