Biology Reference
In-Depth Information
Eureka, there is a condition known as
decorticosis or shell bark. The outer bark
dies, loosens, peels off in longitudinal strips.
New bark forms below this, and the tree may
recover only to develop the disease again in 4
or 5 years. Some leaves and twigs die; the
fungus winters in dead wood.
Control
A single copper spray, bordeaux or
a neutral copper, applied within 1 to 3 weeks
after fruit is set, controls melanose. Copper
applied in summer induces excessive cork forma-
tion in the melanose lesions, a condition known
as
Diplodia zeae (see
Stenocarpella maydis
).
Diplodia Corn Ear Rot
,
Root and Stalk Rot
, seed-
ling blight.
Lasiodiplodia theobromae (formerly
Diplodia
natalensis
).
Diplodia Collar and Root Rot
;
Fruit
Rot
,
Gummosis
, general on citrus, sometimes
peach, mango and avocado. On fruit, the rot
resembles Phomopsis rot in being a leathery pli-
able decay of the stem end. It can be prevented by
spraying with bordeaux mixture, adding 1 %
oil to check the increase in scale insects after
the copper kills entomogenous fungi keeping
them in check. The collar rot may girdle young
trees and produce some gumming. Trees affected
with root rot seldom recover and should be
removed.
Lasiodiplodia theobromae (formerly
Diplodia
theobromae
). Sometimes considered a synonym
of
D. natalensis
but differentiated by pycnidia
developed in a stroma instead of on a subiculum
and by darker spores. Causing rots of tropical
fruits, stem-end rot of avocado and collar rot of
peanuts. The peanut rot appears in Georgia, Flor-
ida and Alabama. Runners and central stem are
invaded; they are brown at first, then black with
pycnidia.
Lasiodiplodia theobromae (formerly
Diplodia
tubericola
).
Java Black Rot
, general on sweet
potatoes, especially in the South. So named
because the first diseased specimens came from
Java; this is strictly a storage rot. The inner part of
the tuber is black and brittle; innumerable
pycnidia are produced under the skin, giving
it a pimply appearance. The potato is finally
mummified. Use care in handling so skins are
not broken or bruised; cure properly after harvest;
have suitable temperature in the storage house.
Stenocarpella maydis (formerly
Diplodia
zeae
).
Diplodia Corn Ear Rot
,
Root and Stalk
Rot
, seedling blight. This is one of several fungi
commonly causing ear rot in corn. The rot is dry,
varying from a slight discoloration of kernels to
complete rotting of the ear. Seedlings and inner
stalks have a dry, brown decay. Another species
(
D. macrospora
) is similar but less common,
found in more humid, warmer regions. The rot
is greater in smutted plants. Treat seed before
planting with Spergon.
▶
star melanose. Applied
early,
it
is
noninjurious.
Diaporthe phaseolorum
Fruit Rot
of pepper
and tomato, also pod blight of
lima bean.
Blights
.
▶
Dichotomophthora
Cankers and Diebacks
.
Dichotomophthora portulacae
Black Stem Rot
on common purslane.
▶
Diplodia
▶
Blights
.
Diplodia
Lasiodiplodia
theobromae
).
Diplodia Collar
and
Root Rot
,
Fruit Rot
,
Gummosis
, general on citrus, some-
times peach, mango and avocado.
Diplodia opuntia
Cladode Rot
of cactus.
Diplodia phoenicum
Leaf and Stalk Rot
of date
palms,
Fruit Rot
. The disease is sometimes fatal
to transplanted offshoots. Leaves decay and
die prematurely; spores are produced in great
abundance. Infection is through wounds. Remove
diseased tissue as far as possible and apply
copper-lime dust.
Diplodia pinastri
Collar Rot
of pine.
Diplodia
natalensis (see
▶
Lasiodiplodia
theobromae
). Sometimes considered a synonym
of
D. natalensis
.
Diplodia
theobromae (see
▶
Lasiodiplodia
theobromae
).
Java Black Rot
, general on sweet
potatoes, especially in the South.
tubericola
(see
▶
