Biology Reference
In-Depth Information
low temperature in transit and market. Amaryllis,
lily, and tulip bulbs may be infected.
Rhizopus oryzae (see
Schizophyllum commune
Wound Rot
, com-
mon on dead parts of living trees- maple,
boxelder, almond, acacia, ailanthus, birch,
catalpa, hickory, peach, pecan and citrus, fig.
Fruiting bodies are small, thin, sometimes
lobed, up to 2 inches wide, fan-shaped with
gray-white downy upper surface, brownish
forked gills on underside, common on fruit
trees. This pathogen also causes wood decay
and decline of apple.
Rhizopus arrhizus
).
▶
Head Rot
on sunflower.
Rhizopus stolonifer
Soft Rot
of
Euphorbia
trigona
.
Roesleria
Ascomycetes, Helotiales
Sclerotinia
Mycelium inconspicuous; apothecia cup-shaped,
opening more or less completely; asci disappearing
early, leaving a persistent mass of spores and
paraphyses. Spores hyaline, one-celled, globose.
Roesleria hypogaea
Root-Rot
of grape.
Blights
.
Botryotinia narcissicola (formerly
Sclerotinia
narcissicola
).
Narcissus Smoulder
. Perhaps the
fungus should be transferred to
Botryotinia
, since
there is a conidial stage. The disease is a decay of
stored narcissus bulbs, also known on snowdrop,
and a rot of foliage and flowers in the open,
especially during cold wet seasons. Leaves are
distorted, stuck together as they emerge from soil.
Sclerotia are small, black, flattened bodies, up to
1/2 inch long when several grow together, just
below outer papery bulb scales. In prolonged
storage there is a yellow-brown rot.
Control
Remove and destroy diseased plants as
soon as noticed; destroy weeds to provide air
circulation; spray with bordeaux mixture; discard
rotting bulbs at harvest; change location every
year.
Sclerotinia homoeocarpa
Dollar Spot
.
Small
Brown Patch
of turf on bent grasses, fescues
and bluegrass. Spots are brown at first, then
bleached and straw-colored, about 2 inches in
diameter but coalescing to large irregular
patches. While leaves are being killed, a fine
white cobwebby growth of mycelium can be
seen in early morning when dew is present.
Sclerotinia intermedia
Stem Rot
, market dis-
ease of celery, carrot and salsify.
Sclerotinia minor
Stem Rot
of lettuce, celery,
carrot, cocklebur, Austrian winter pea, lana
woolly pod vetch, phacelia and basil; also
stem rot on fennel, root and crown rot on cab-
bage, crown rot and wilt on
Cichorium
(
radicchio
).
Root and Pod Rot
of peanut.
▶
Rosellinia
Ascomycetes, Xylariales
Perithecia smooth, ostiole simple or with a low
papilla; with a subicle under the fruiting layer;
paraphyses present; spores olive to brown, one-
celled.
Rosellinia necatrix (Syn.
Dematophora
).
White Root Rot
of fig, grape, avocado, apricot,
cherry, apple, pear, peach, walnut, holly
osmanthus, privet and poplar. This is like
Armillaria root rot in that all trees in a certain
area are killed, but there are no rhizomorphs or
toadstools formed. A white mycelial growth on
surface of affected roots turns black and cob-
webby. During wet weather a delicate mold
forms on surface of bark and on soil around base
of tree. Foliage is sparse and wilting, growth slow
or none. Crabapples are quite resistant. Plums and
apricots can be grown on resistant understock.
Schizophyllum
Basidiomycetes, Aphyllophorales
Pileus leathery; stipe lateral or none; edge of gills
split; spores white.
