Biology Reference
In-Depth Information
Control
Use resistant plants where possible. Of
fruits, only French pear, Northern California
black walnut, fig and persimmon are sufficiently
resistant to grow safely on infested soil. Some
plants can be grafted onto resistant rootstock
such as Myrobalan 29. The University of Califor-
nia has prepared a list of resistant or moderately
resistant ornamental shrubs. Some on the list are
Acacia decurrens
var.
mollis, A. verticillata,
Buxus semipervirens, Ilex aquifolium, Lonicera
nitida, Prunus ilicifolia
(hollyleaf cherry),
P.
lyoni
(Catalina cherry),
Pyracantha coccinea
and var.
lalandii
but not
P. angustifolia
, which
is susceptible.
Moderately resistant shrubs include
Abelia
grandiflora
, Darwin, Japanese, and Mrs. Wilson
barberry, Mexican orange (
Choisya
),
Elaeagnus
argentea, Euonymus japonica
, Japanese privet,
Myrtus communis, Pittosporum tobira
and
Spi-
raea prunifolia
.
Mechanical measures are often helpful.
Excavate and expose the root crown; remove
diseased portions of bark and affected small
roots. Paint wounds with a pruning wound com-
pound. Leave the treated roots exposed until
cool weather in autumn. Trenching or digging
a ditch around a plot will restrict the disease
temporarily, but roots will grow through the
ditch in time.
Carbon disulfide is still recommended as a soil
disinfectant, applied in staggered rows, in holes
18 inches apart each way, which should be imme-
diately closed by tamping. Hand applicators are
available for injecting the disulfide 6 to 7 inches
deep. This treatment is for land where valuable
trees have been removed; one cannot go closer to
a healthy tree than the edge of the branch spread.
After treatment, the land should remain fallow for
at least 60 days, and then be ploughed before
planting.
definitely a foot rot, with infection at the root
crown or base of stem.
Aspergillus
Deuteromycetes, Coelomycetes
Conidiophores have a round head at the top, with
radially arranged bottle-shaped sterigmata that
bear conidia in chains; spores are one-celled,
globose to ellipsoid, hyaline. Bread molds are in
this genus. When, rarely, a sexual fruiting body
(cleistothecium) is formed, the species is placed
in the order Eurotiales.
Aspergillus alliaceus
Cladode Rot
,
Stem and
Branch Rot
on
Cereus
and
Opuntia
cacti. This is
a high temperature species. Spores are yellow in
mass.
Aspergillus fumigatus
Wound Rot
(storage) on
beet.
Aspergillus niger
Calyx-End Rot
of dates,
Fig
Smut
,
Bunch Mold
of grapes,
Pomegranate Rot
,
Black Mold
of peach.
Crown Rot
of peanut; also
market and storage rot of shallot, onion, apple
and potatoes. The fungus is a weakly parasitic
black mold invading ripe tissue through wounds.
In dates, the interior of the fruit is filled with
a black dusty mass of spores, spread to a large
extent by the dried-fruit beetle. Practice orchard
sanitation; keep decaying fruits cleaned up so
insects cannot carry spores.
Aspergillus niger var. floridanus Wound para-
site on
Dracaena
. Lower stem black, rotted, with
dark brown spore masses.
Aspergillus spp. Green and yellow molds caus-
ing secondary rots of many fruits and some veg-
etables in storage.
Lasiodiplodia (Botryodiplodia)
Ascochyta
Blights
.
Botryodiplodia
▶
theobromae (see
Blights
.
Ascochyta pinodes
Foot Rot
of peas.
Of the three species that make up the Ascochyta
blight
Lasiodiplodia theobromae
).
Root Rot
on apple
Lasiodiplodia theobromae (formerly
Botryodiplodia theobromae
).
Root Rot
on
apple.
▶
▶
complex,
this
one
produces most
