Biology Reference
In-Depth Information
across to adjacent healthy scales. Rotted tissue is
chocolate or purplish brown, the mycelium
a delicate weft of white or pink threads. The rot
is dry, spongy, with little external evidence; it is
primarily a storage or transit disease, but it may
occur in the field late in the season. When lightly
infected bulbs are planted, there is no root devel-
opment, and plants are stunted. Basal rot is spread
in hot-water treatment for nematodes. It is more
prevalent where soil temperatures are above 65
F
and on large trumpet varieties. Golden Harvest is
much more susceptible than King Alfred.
Control
Discard all bulbs showing rot, or that are
soft when pressed; if disease has occurred previ-
ously, plant in a new location.
Fusarium oxysporum f. sp. radicis-
lycopersici
Root and Crown Rot
of tomato.
Fusarium oxysporum var.
brownish red or crimson. Infection is only
through injured, weak or old tissue.
Fusarium semitectum
Corky Dry Rot
on
cantaloupe.
Fusarium solani
Tuber Rot
on caladium and
Stem Rot
on chrysanthemum, Fraser fir, Doug-
las-fir, dieffenbachia (cutting rot), and sweet
potato (root rot); shefflera is susceptible with no
symptoms. Root rot; this pathogen also causes
root rot of apple.
Root and Crown Rot
of leafy
spurge.
Fusarium solani (Teleomorph,
Nectria
haematococca
).
Stem Rot
and
Wilt
of
Exacum
.
Fusarium solanif. sp. cucurbitae (Teleomorph,
Hypomyces solani
).
Fusarium Root Rot
of cucur-
bits, primarily pumpkin and squash, occasionally
muskmelon, watermelon and cucumber. The fun-
gus usually girdles the plant at ground level with
a soft dark decay, resulting in a striking wilt of the
entire vine. Fruits on the ground may be rotted
and the fungus carried on seed to infest clean soil.
Do not plant cucurbits in land known to be
contaminated.
Fusarium solani f. sp. phaseoli
Dry Root Rot
of
bean and lima bean, common but most important
in New York, Idaho and other areas intensively
cropped for many years. Indefinite reddish
lesions or streaks on taproot and subterranean
stem turn dark brown to black. Lateral roots are
reduced and plants stunted. This is a late season
disease favored by warm soil. The fungus winters
in crop refuse and soil and may be carried in dust
on seed. The best control
redolens
Root
Lesions
of pine.
Fusariumpoae
Carnation Bud Rot
,
Silver Spike
Disease
of bluegrass. The interior of carnation
buds is brown or pink, decayed, moldy and
often infested with grass mites, which have intro-
duced the spores. The disease is favored by
excessive dampness. Pick and destroy diseased
buds; control mites.
On bent grasses, fescues and especially Ken-
tucky bluegrass, seed heads wither before they
are fully expanded, appearing silvery. Seeds are
aborted, and in moist weather copious mycelium
grows from decayed areas in culms. The patho-
gen is disseminated and grass inoculated by the
grass mite (
Siteroptes graminum
). Burning over
dead grass is a practical means of control.
Fusarium proliferatum
Root Rot
and
Stem
Wilt
on asparagus in CT.
Root Rot
and
Crown
Rot
of clovers and leafy spurge,
Bulb Rot
of
onions.
Fusarium roseum
Peppermint Root
and
Rhi-
zome Rot
. Reported from Oregon as part of
a complex with
Rhizoctonia solani
and
Pythium
sp. Necrotic lesions girdle rhizomes; new shoots
damp-off. Fall-plowed mint gave stronger stands.
This pathogen also causes seedling stem rot on
Douglas-fir.
Fusarium cerealis
Stem Rot
of carnation and
cereals. Roots and stems of cuttings and young
plants rot; in older stock the diseased tissue turns
is a long rotation
between crops.
Fusarium solani f. sp. pisi
Root Rot
on chick-
pea, spruce, pine, fir, and hemlock.
Fusarium subgutinans
Collar Rot
and
Foliar
Blight
on Chinese evergreen.
Fusarium sp.
Root and Seed Rot
of bird-of-
paradise (
Strelitizia
), part of a fungus complex.
Controlled by treating seed in hot water, 135
F
for 30 min, and immediately cooling in cold
water and treating planting medium with methyl
bromide or steam.
Fusarium sp.
Dill Root Rot
,
Wilt
, discovered in
Ohio in 1949. Symptoms include browning of
roots, necrosis of vascular system, yellowing,
wilting and death. Young plants are most
