Agriculture Reference
In-Depth Information
obvious at planting. Material removed during showery
weather and stored in heaps is particularly prone to
infection. Tops (crowns) used for planting are particularly
susceptible. Conidia are produced under conditions of high
humidity and can be dispersed by wind.
Importance
Losses of planting material and plantings from diseased
material can be severe.
Management
•
Do not leave a portion of fruit attached to the crown
when picking.
Fig 16.6 Internal symptoms of fruitlet core rot on rough-leaf Queen
fruit.
Treat material to be planted with a recommended
fungicide immediately after removal (without drying).
•
Store planting material on top of plant rows in a single
layer with the butts exposed to the sun, or lay them
on the ground in a similar manner. Losses are reduced
greatly by curing the planting material base. If prolonged
wet weather occurs, spray upturned butts or dip with a
recommended fungicide within fi ve hours of harvesting.
•
the rough-leaf Queen group may produce fruitlets that fail
to colour - a condition often referred to as 'green eye'.
Severely affected fruitlets may become brown and sunken
as the fruit ripens.
Internal symptoms consist of a browning of the centre of
the fruitlets starting below the f floral cavity and sometimes
extending to the core. The browning, which remains quite
firm, varies in size from a speck to complete discolouration
of one or more fruitlets.
Improve soil drainage and avoid planting during wet
weather.
•
FRUITLET CORE ROT (GREEN EYE)
■
Source of infection and spread
Penicillium funiculosum
infects the developing fruit at some
stage between initiation and open f flower. Infection is
favoured by cool temperatures (16-20
Cause
The fungi
Fusarium guttiforme
(previously
moniliforme
)
and
Penicillium funiculosum
.
C) during the five
weeks after f flower initiation, during which time the fungus
builds up in leaf hairs damaged by mites. Similar cool
temperatures are required for infection from about 10-15
weeks after f flower induction. Temperatures above 20°C
°
Symptoms
This is an internal fruit disease. Smooth Cayenne fruit do
not usually show any external symptoms. However, fruit of
Fig 16.5 External symptoms of fruitlet core rot. This shows the
'green-eye' symptom of the disease on rough-leaf Queen fruit.
Fig 16.7 Symptoms of fruitlet core rot on a fruit cylinder.
