Agriculture Reference
In-Depth Information
FIG
(
Ficus carica
)
GUAVA
(
Psidium guajava
)
RUST
■
Cause
The fungus
Cerotelium fici
.
ANTHRACNOSE
■
Cause
The fungus
Colletotrichum acutatum
.
Symptoms
Angular lesions cause leaf spots that range in colour from
pale to reddish brown. In severe cases of premature
defoliation, fruit drop may result.
Symptoms
Lesions appear as tan discolourations of the skin.
These develop into circular, somewhat sunken spots
with a salmon colour. The lesions often coalesce to
form a large rotted area extending well into
the flesh.
Source of infection and spread
It is believed that the fungus overwinters as uredospores on
fallen leaves that infect young leaves in spring. Knowledge
of the life cycle is incomplete.
Source of infection and spread
Infection by
Colletotrichum
spp. occurs before harvest.
Spores of the fungus are produced on dead and dying plant
material and are spread to fruit during wet weather.
Infections in the skin remain latent until ripening, after
which they develop rapidly.
Importance
Rust can cause severe leaf fall in orchards.
Management
•
Rake fallen leaves and destroy.
Importance
Anthracnose causes occasional losses of harvested fruit.
Spray with recommended fungicides.
•
PHYTOPHTHORA FRUIT ROT
■
Cause
The oomycete
Phytophthora
spp. (refer to the chapter on
Common diseases of perennial fruit crops).
Management
•
Remove dead and dying plant foliage from trees.
Avoid unnecessary wetting of the foliage and fruits.
•
Importance
Minor problem following wet weather.
Fig 19.10 Fig fruit infected with Phytophthora fruit rot showing
typical white growth.
Fig 19.11 Anthracnose symptoms on guava.
