Biology Reference
In-Depth Information
mummified. The fungus is spread in irrigation
water, crop debris, imported soil and on seed.
Control
Use bean seed grown in western dis-
ease-free regions. Keep plants growing vigor-
ously with proper
Monilinia
Blights
.
Monilinia fructicola (Syn.
Sclerotinia
fructicola
).
Brown Rot
of stone fruits, blossom
blight, general on peach, plum and cherry, also on
apricot, almond, beach-plum, Japanese quince,
and, rarely, apple and pear. The fungus is distinct
from the species in Europe (
Sclerotinia
fructigena
) causing brown rot of stone fruits and
also a serious apple rot. In the United States,
brown rot is our most destructive stone-fruit
disease, causing an annual peach loss of over
$5 million.
Monilina fructicola
is the usual caus-
ative agent east of the Rocky Mountains;
M. laxa
causes a similar rot and blossom blight on the
Pacific Coast. See also
▶
food and water; practice
general sanitation.
Macrophomina phaseolina
Charcoal Rot
on
soybean, sunflower,
Amaranthus, Euphorbia
spp.,
Ipomea, Sonchus
and
Tidestrominia
; root
rot on caper spurge.
Magnaporthe
Ascomycetes, Diaporthales
This is characterized by the production of peri-
thecial ascocarps produced in a stroma of fungal
and substrate tissues or directly from somatic
hyphae on the substrate.
Magnaporthe poae Summer patch and large
brown patch on grass.
Blights
.
Flowers turn brown prematurely, rot in moist
weather; the calyx cup is blackened, and the
discoloration may extend down into the pedicels.
Infrequently there is a leaf and twig blight; can-
kers are formed on the larger limbs, with exuda-
tion of gum. The fruit rot is the familiar stage seen
in any backyard with a fruit tree and usually in
baskets of peaches, plums or cherries purchased
for preserving and held over to the next day. The
rot starts as a small, circular brown spot but
spreads rapidly to take in the entire fruit, with
the rotted surface covered with gray to light
brown spore tufts or cushions (sporodochia),
sometimes in concentric rings (see
Fig. 5
).
Conidia are formed in chains on the sporodochia.
The fruit finally shrinks and mummifies and
either falls to the ground or remains clinging to
the tree.
The fungus and decayed tissue together
form a stroma that acts as a sclerotium; in
spring, if the mummy has been kept moist
and partially or wholly covered with soil,
cup-shaped brown apothecia are produced. Pri-
mary infection is from ascospores, forcibly
ejectedandcarrieduptoblossomsbyaircur-
rents or from a new crop of conidia formed on
mummies hanging on trees. Secondary infec-
tion is from conidia wind-borne from blossom
to blossom and later
▶
Melanconium
▶
Leaf Spots
.
Greeneria uvicola (formerly
Melanconium
fuligineum
).
Bitter Rot
of grapes, widespread
but especially serious on Muscadine grapes in
Georgia. Decayed berry pulp has a bitter
taste; up to 30 % of fruit is reduced to dry, hollow
shells. Spray with bordeaux mixture three
times at 14-day intervals beginning after fruit is
set. The later sprays for black rot should control
bitter rot.
Melanconium fuligineum (see
Greeneria
uvicola
).
Bitter Rot
of grapes, widespread but
especially serious on Muscadine grapes
▶
in
Georgia.
Mycocentrospora
Deuteromycetes, Hyphomycetes
Mycocentrospora acerina
Dry Rot
of carrot.
from fruit
to fruit.
