Host Plants - Westcott's Plant Disease - page 563

Verticillium wilt is the most destructive maple
disease and is particularly prevalent in street
trees. The wilting may be confined to a single
branch, which can be cut out, or may kill the
whole tree. In removing dead trees, get all of the
root system and replace with a different kind of
tree. Leaf scorch is common on sugar maple in
hot, windy weather; anthracnose may be conspic-
uous in wet weather.

B LIGHT , Head. Botrytis cinerea, AK, CT, NJ, PA;
Helminthosporium sp., TX.
B LIGHT , Southern. Sclerotium rolfsii, FL, NJ,
VA.
L EAF S POT . Alternaria tagetica, SC, NJ;
Cercospora sp., CT, C. tageticola, FL;

Septoria tageticola, FL.
N EMATODE . Aphelenchoides tagetae, MD;
Paratylenchus micoletzkyi, MD.
N EMATODE , Root Knot. Meloidogyne hapla, VA.
N ONPARASITIC Air Pollution.NO 2 ,SO 3 ,O 3 , NC.
R OT , Charcoal. Macrophomina phaseoli, OK.
R OT , Root. Pythium ultimum, CA; Rhizoctonia
solani, TX.
R OT , Stem; Wilt. Sclerotinia sclerotiorum, NY;
Phytophthora cryptogea, NY; Fusarium
sp., CA, NJ, NY.
R UST . Coleosporiummadiae (II, III), CA; 0, I on
pine; Puccinia tageticola (II, III), TX.
V IRUS . Cucumber Mosaic, FL.
W ILT . Fusarium oxysporum f. sp. callistephi,
CA;

Marah

V IRUS . Wild Cucumber Mosaic, CA, OR.

Maranta (Calathea)

L EAF S POT . Glomerella cincta, NJ; Phyllosticta
sp., NJ; Drechslera setariae, FL.
R UST . Puccinia cannae (II, III), FL.
V IRUS , Mosaic. Sugarcane Mosaic, FL.

Verticillium alboatrum, NY;

V. dahliae, AZ.
Marigolds are easy to grow without paying too
much attention to disease. Cut fading flower
heads off into a paper bag before the gray mold
of Botrytis blight gets started.

Marguerite (Argyranthemum
frutescens)

B ACTERIAL Crown Gall. Agrobacterium
tumefaciens, IA, MD, NJ, NY, VA.
B ACTERIAL , MLO. Aster Yellows, KS, NJ, NY,
and California Aster Yellows, CA.
D OWNY M ILDEW . Peronospora radii, CA.
N EMATODE , Root Knot. Meloidogyne sp.
P OWDERY

Mariposa-Lily, Globe-Tulip
(Calochortus)

R UST . Puccinia calochorti (0, I, III), CA, OR,
WA to NE, NM.

M ILDEW . Golovinomyces

cichoracearum, NJ.
V IRUS . Beet Curly Top, CA.
W ILT . Verticillium albo-atrum, NJ.

Marshelder (Iva xanthifolia)

D OWNY M ILDEW . Plasmopara halstedii,ND.

Marigold (Tagetes)

Marsh-Marigold (Caltha)

B ACTERIAL Leaf Spot. Pseudomonas syringae
pv. tagetis, NC.
B ACTERIAL , MLO. Aster Yellows, CT, NJ, NY,
PA, WI; California Aster Yellows, CA.
B ACTERIAL Wilt. Pseudomonas solanacearum,
FL.
B LIGHT . Alternaria tagetica, SC.

G ALL , Leaf. Synchytrium aureum, WI.
L EAF S POT . Cercospora calthae, WI;
Cylindrosporium sp., NY; Fabraea
rousseauana, CA, WI; Ramularia calthae,
NY, WI.