Host Plants - Westcott's Plant Disease - page 666

L EAF S POT . Mycosphaerella pontederiae, ME,
MI, NY, VA, WI; Phyllosticta fatiscens, IA,
NJ, NY, WI.
S MUT , White. Entyloma nymphaeae, CT, IL,
MA, WI.

P OWDERY M ILDEW . Golovinomyces
cichoracearum, AZ, CA, FL, GA, NY, NC,
TX, VA. May make pimples in young fruit;
Podosphera xanttii, FL.
R OT . Diplodia spp., stem-end, gray; MD to FL,
AZ, KS; Fusarium scirpi, occasional in mar-
ket; Helminthosporium sp., TX; Rhizopus
spp., mushy soft rot.
R OT , Charcoal. Macrophomina phaseoli, TX.
R OT , Root. Acremonium sp., CA;
Phymatotrichum omnivorum, AZ, TX;
Thielaviopsis basicola, OR, UT;
Monosporascus cannonballus, CA, Brazil.
R OT , Stem and Fruit. Phytophthora cactorum,
AZ; P. capsici, CO; P. citrophthora, CA;
Sclerotinia sclerotiorum, NJ, TX.
S CAB ; Leaf Mold. Cladosporium cucumerinum,
MD, NE.
V IRUS . Watermelon Mosaic, NY to FL, AZ, CA,
IA, MI, TX, WA; Beet Curly Top; Tobacco
Ring Spot; Watermelon Stunt (strain of
Squash Mosaic); Zucchini Yellow Mosaic,
CA; Watermelon Curly Mottle, AZ; Papaya
Ring Spot, LA; Squash Leaf Curl, TX; Let-
tuce Infectious Yellows, AZ, CA, TX;
Tomato Spotted Wilt, GA; Cucurbit Leaf
Crumple, CA; Squash Vein Yellowing, IN;
Cucurbit Yellow Stunting, AZ, Mexico.
W ILT . Fusarium oxysporum f. sp. niveum, GA,
general and Race 2, DE, IN, MD; Race 3, MD;
Verticillium albo-atrum, CA, NH, OR;
V. dahlia, TX, Rhizoctonia solani AG-7, IN.
Fusarium wilt is probably the major disease
and resistant varieties are available. For anthrac-
nose and leaf spots treat seed before planting, and
start spraying or dusting when vines start to run.

Watermelon (Citrullus)

A NTHRACNOSE . Colletotrichum lagenarium,
general, Pacific Coast; C. orbiculare, CA;
Marssonina melonis, NY.
B ACTERIAL , Angular Leaf Spot. Pseudomonas
pseudoalcaligenes subsp. citrulli, GA.
B ACTERIAL Fruit Blotch. Acidovorax avenae
(syn. Pseudomonas pseudoalcaligenes)
subsp. citrulli, DE, IL, IN, OR, TX.
B ACTERIAL Rind Necrosis. Erwinia sp., TX.
B ACTERIAL Soft Rot. Erwinia aroideae, WV;
wilt, E. tracheiphila, rare.
B ACTERIAL Spot. Pseudomonas lachrymans, MI.
B ACTERIAL Wilt. Erwinia tracheiphila, NM.
B LIGHT , Gummy Stem; Fruit Spot. Didymella
bryoniae, CA; Mycosphaerella citrullina,
also stem-end rot, leaf spot, MA to FL, AZ,
MO.
B LIGHT , Southern. Sclerotium rolfsii, also fruit
rot, NC to FL, TX.
C ANKER , Stem. Myrothecium roridum, GA.
D AMPING -O FF . Rhizoctonia solani, soil rot, leaf
blight; Pythium spp., also blossom-end rot,
foot rot.
D OWNY M ILDEW . Pseudoperonospora cubensis,
occasional from MA to FL, TX, WI; also CA.
F RUIT S POT ;Speck.Cribropeltis citrullina,IL.
L EAF S POT . Alternaria cucumerina, general
except Pacific Coast; A. alternate f. sp.
cucurbitae, MD. Cercospora citrullina,NJ
to FL, OH, TX; Corynespora cassiicola;
Myrothecium roridum, GA.
N EMATODE , Root knot. Meloidogyne arenaria;
M. incognita; M. javanica.
N ONPARASITIC . Blossom-End Rot. Hot dry
weather after cool, moist days.
Internal Browning. Drought and nutritional
deficiencies.

Water-Primrose (Jussiaea)

L EAF S POT . Alternaria sp. OK; Cercospora
jussiaeae, AL, OK, TX; Colletotrichum
jussiaeae AL, TX; Septoria jussiaeae AL,
FL, LA, TX.
R UST . Aecidium betheli, CA; Puccinia jussiaeae
(0, I, III), MS; Uredo guaunabensis (II), FL.