Agriculture Reference
In-Depth Information
After harvest, dip fruit for one minute in calcium
hypochlorite to remove the dark growth of the fungus.
•
STEM-END ROT
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Cause
Stem-end rot is caused by several species of fungi and
bacteria; principally,
Fusicoccum aesculi (Dothiorella
aromatica), Lasiodiplodia theobromae and Colletotrichum
gloeosporioides. Phomopsis perseae
and
Thyronectria
pseudotrichia
may also be involved.
Symptoms
Stem-end rot is a dark brown to black rot of the fruit
starting at the stem end. With the exception of stem-end
rot caused by
C. gloeosporioides
, vascular tissue discolours,
typically in advance of f flesh symptoms.
Source of infection and spread
The stem-end rot fungi live within healthy stem tissue
as latent and/or endophytic infections. Infection may occur
as endophytic colonisation of the inf lorescence and
stem-end tissue of fruit before harvest.
Fig 4.23 Superficial fungal growth on fruit caused by sooty blotch.
Inset: early stage.
Importance
This is a minor disease. If not controlled, the disease may
reduce photosynthesis of leaves, discolour fruit and reduce
its market value.
Management
•
Use the fi eld spray program for anthracnose to control
sooty blotch.
Fig 4.24 Sooty blotch symptoms on branches.
Fig 4.25 External symptoms of stem-end rot on a green-skinned variety.