Agriculture Reference
In-Depth Information
SEPTORIA SPOT
■
Cause
The fungus
Septoria passifloricola
.
Symptoms
Leaves: brown, slightly rounded spots 2-8 mm wide occur
on leaves with minute, black fruiting bodies (pycnidia)
scattered over the surface. Infected leaves fall readily and
vines may be defoliated.
Stems: similar spots to those on leaves may occasionally
occur on stems.
Fruit: light brown blotches studded with minute, black
pycnidia develop, lesions often coalesce to cover large
areas of the fruit, and these lesions have dark borders.
Infected fruit ripens unevenly. Granadilla (
Passif lora
quadrangularis
) shows similar symptoms.
Fig 15.19 Septoria spot showing minute, black fruiting bodies.
Importance
Septoria spot can cause serious fruit losses, particularly in
wet seasons. Infected fruit are only suitable for processing.
Vines are more likely to develop the disease when stressed,
hence the disease can also become a problem when vines
decline during winter.
Source of infection and spread
Spores produced in the fruiting bodies are blown to
adjacent vines during wet, windy weather. Warm, moist
weather favours the disease. Infection of the fruit may take
place at any stage of development. Spores of the fungus are
also spread by insects.
Management
•
Spray with recommended fungicides.
Prune vines to reduce density and allow better spray
penetration.
•
Plant resistant varieties.
•
VIRUSES
WOODINESS DISEASE
■
Cause
Usually, woodiness disease is caused by
passionfruit
woodiness virus
alone or in combination with
clover yellow
vein virus, passiflora virus Y
and
passiflora latent virus.
Fig 15.20 Passionfruit woodiness disease. Compare the affected,
distorted fruit with the healthy, smooth fruit.
Fig 15.18 Septoria spot on green fruit.
