Biology Reference
In-Depth Information
daylilies and many other plants and perhaps
weakly parasitic.
Colletotrichum lilii (formerly
Colletotrichum
liliacearum
). Found on dead stems of daylilies
and many other plants and perhaps weakly
parasitic.
Colletotrichum
the centers of such spots are covered with gelat-
inous masses of salmon-colored spores. Infected
fruit has a bitter taste or the flesh is tough and
insipid. Soft rots often follow the anthracnose.
Epiphytotics occur only in periods of high rainfall
and temperature, near 75
F.
Control
Treating seed before planting is essen-
tial. Use a three year crop rotation with non-
cucurbits; destroy plant refuse. Watermelon
varieties Charleston Gray, Congo, Fairfax, and
Black Kleckly are resistant but not to all races
of the fungus.
Colletotrichum
lindemuthianum (
▶-
Glomerella lindemuthianum
).
Bean Anthrac-
nose
, a major bean disease, sometimes
mistakenly called “rust,” generally present in
eastern and central states, rare from the Rocky
Mountains to the Pacific Coast.
Colletotrichum malvarum
Hollyhock
Anthracnose
,
Seedling Blight
on hollyhock,
mallow, and abutilon, particularly destructive to
greenhouse seedlings. Black blotches are formed
on veins, leaf blades, petioles, and stems.
Remove and burn all old plant parts in autumn.
Colletotrichum
Glomerella
cingulata
).
Tomato Anthracnose
, common rot
of ripe tomatoes, most frequent in Northeast and
North Central districts. Symptoms appear late in
the season, causing more loss to canning crops.
Small, circular sunken spots, increasing to an
inch in diameter, penetrate deeply into the flesh.
At first water-soaked, the spots turn dark, with
pinkish, cream, or brown spore masses in the
depressed centers, often arranged in concentric
rings. The disease is worse in warm, moist
weather. The fungus winters in tomato refuse,
sometimes in cucumber and melon debris.
Control
Clean up trash and rotting fruit.
Colletotrichum pisi (
Glomerella cingulata
).
Pea Anthracnose
,
Leaf and Pod Spot
commonly
associated with Ascochyta blight and often
a secondary parasite.
Colletotrichum schizanthi
Anthracnose
on
butterfly-flower. Symptoms are small brown
spots on leaves and water-soaked areas on
young stems. Cankers on stems and branches of
older plants may cause leaves to turn yellow,
branches to die back from the tip, and finally
death of all parts above the canker.
Colletotrichum
phomoides
(
▶
omnivorum (see
Colletotrichum dematium
).
Anthracnose
on
aspidistra and hosta. Large, whitish spots with
brown margins are formed on leaves and stalks.
Remove and burn infected plant parts.
Colletotrichum orbiculare
Anthracnose
on
watermelon.
Colletotrichum orbiculare (formerly
Colletotrichum lagenarium
).
Melon Anthrac-
nose
on muskmelon, watermelon, cucumber,
and other cucurbits. This is our most destructive
disease of watermelons, found everywhere that
melons are grown and particularly destructive in
the South. There are at least three races of the
fungus differing in ability to infect different
cucurbits. One race is virulent on cucumber,
slight on watermelon, moderate on Butternut
squash; another is virulent on both watermelon
and cucumber; Butternut squash is immune to
a third.
Leaf symptoms are small yellow or water-soaked
areas, which enlarge and turn black on water-
melon, brown on muskmelon and cucumber.
The dead tissue shatters; leaves shrivel and die.
Elongated, narrow, sunken lesions appear on
stems and petioles; vines may die. Young fruit
darkens, shrivels and dies if pedicels are infected;
older fruit shows circular, black, sunken cankers
or depressions, from 1/4 to 2 inches across and
1/3 inch deep on watermelon. In moist weather
▶
sublineola (see
Colletotrichum graminicola
).
Anthracnose
on
wild rice (
Zizania
).
Colletotrichum trichellum
Fruit Anthracnose
of tomato and Hedera.
Colletotrichum truncatum
Stem Anthracnose
prevalent in the South on bean, lima bean, and
soybean, also on clovers and on lentil in ND.
Brick-red spots appear on veins on underside of
leaves and on pods. Plants are chlorotic, stunted,
may die prematurely; blossoms or pods may drop.
▶
