Biology Reference
In-Depth Information
cucumber. Gray to brown dead areas in leaves
are marked with black pycnidia; leaves may turn
yellow and shrivel. Stem infection starts with
a water-soaked oily green area at nodes. The
stem is girdled, covered with a dark exuded
gum, and the vine wilts back to that point. Fruit
rot starts gray, darkens to nearly jet black, with
gummy exudate.
Control
Clean up crop refuse; practice rotation.
Some varieties are more resistant than others.
Mycosphaerella fijiensis
Black Sigatoka
on
dwarf banana in FL.
Mycosphaerella melonis
Gummy Stem Blight
of cucumbers.
Mycosphaerella
Monilinia (Sclerotinia)
Ascomycetes, Helotiales,
Sclerotiniaceae
Stroma is a sclerotium formed in fruit by the
fungus digesting fleshy tissues and replacing
them with a layer of broad, thick-walled, inter-
woven hyphae forming a hollow sphere enclosing
core or seed of fruit, which has become a dark,
wrinkled, hard mummy. Apothecia funnel-form
or cupulate, rarely flat-expanded, some shade of
brown; asci eight-spored; ascospores one-celled,
ellipsoidal, often slightly flattened on one side,
hyaline. Conidia hyaline, one-celled, formed in
chains in grayish masses called sporodochia.
Monilinia azaleae
Shoot Blight
of native or
pinxter azalea (
Rhododendron roseum
).
Apothecia are formed on overwintered mummied
fruits (capsules) in leaf mold under shrubs in
moist places. Ascospores infect leaves and suc-
culent shoots when the azalea is in full bloom.
The conidial stage is common on young develop-
ing fruits in late June and July (New York).
Monilinia fructicola
Leaf Blight
and
Shoot
Blight
of peach.
Monilinia johnsonii
Leaf Blight
,
Fruit Rot
of
hawthorn.
Monilinia laxa
Blossom Blight
,
Brown Rot
of
apricot, almond, cherry, plum, and prune on
Pacific Coast. Blossoms and twigs are blighted
with a good deal of gum formation.
Monilinia
laxa
is sometimes coincident with, and confused
with,
M. fructicola
, which causes a more general
rot of stone fruits. Both are discussed more fully
under Rots.
Monilinia rhododendri (
Sclerotinia seaveri
).
Twig Blight
,
Seedling Blight
of sweet cherry.
pinodes
Pea
Blight
.
Ascochyta pinodes
.
Mycosphaerella
▶
rabiei
(Anamorph,
Phoma
rabiei
).
Blight
of chickpea
Mycosphaerella sequoiae
Needle Blight
of
redwood.
Myriogenospora
Ascomycetes, Hypocreales
Ascomata superficial or in a stroma, fleshy,
bright-colored; ascus with a thick cap traversed
by
a
slender
pore;
ascospores
filifrom,
multiseptate, often fragmenting.
Myriogenospora atramentosa
Blight
on turf
grass, centipedegrass.
Mystrosporium
Deuteromycetes, Hyphomycetes
Conidia dark, muriform; hyphae long.
Bipolaris iridis (formerly
Mystrosporium
adustum
).
Leaf Blight
,
Ink Spot
of bulbous iris;
also on montbretia and lachenalia. Irregular black
patches or blotches appear soon after leaves push
through the ground; under moist conditions the
foliage withers and dies prematurely. Inky black
stains appear on husks of bulbs (usually
Iris
reticulata
), and yellow dots or elongated sunken
black craters show on fleshy scales. The bulbs
Mycosphaerella
Anthracnose
.
Mycosphaerella citrullina (
M. melonis
) conid-
ial stage
Didymella bryoniae
.
Gummy Stem
Blight
,
Stem End Rot
,
Leaf Spot
of watermelon,
muskmelon,
▶
summer
squash, pumpkin, and
