Post harvest diseases fruits and vegetables - Xavier University ...

FREEDOM PALESTINE FREEDOM PALESTINE FREEDOM PALESTINE
288 Postharvest Diseases of Fruits and Vegetables
since the fruit may mature and ripen during this period. Both orchard
spraying and postharvest fungicidal dips have been used to control
postharvest avocado diseases (Darvis, 1982; Muirhead et al., 1982).
A reduction of the incidence of postharvest anthracnose of avocado was
recorded after dipping or spraying with an antioxidant compound, which
led to the maintenance of host resistance. A combination of the
antioxidant with fungicide (prochloraz) application reduced decay
consistently and for a longer period, while fungicidal treatments alone
did not always result in disease reduction (Prusky et al., 1995).
Looking for a non-chemical method to control postharvest diseases of
avocados in South Africa, Korsten et al. (1995) evaluated the inhibitory
capacity of bacteria isolated from avocado leaf and fruit surfaces, against
fruit pathogens. Bacillus subtilis, when incorporated into the commercial
wax and applied to the fruit in the packinghouse, was found to be the
most effective antagonist against the Dothiorella/Colletotrichum fruit rot
complex and against stem-end rot.
Under commercial conditions, decay development can be delayed by
storing the fruit at 5-6*^0 for short-term shipping or storage. However,
several cultivars are sensitive to such low temperatures and should be
stored at higher temperatures. A controlled atmosphere of 2% O2 and
10% CO2 at 7°C can extend the storage period of avocados (Spalding and
Reeder, 1975). When the fruit must be held for longer periods, a
combination of low temperatures and fungicide treatments is needed
(Muirhead et al., 1982).
PINEAPPLE
The main postharvest diseases of pineapple are black rot, caused by
Thielaviopsis paradoxa, and fruitlet core rot, caused by several wound
pathogens.
1. Thielaviopsis paradoxa (de Seynes) Hohnel [perfect state:
Ceratocystis paradoxa (Dade) Moreau]
This fungus is the cause of black rot, which is the most significant
postharvest disease of pineapple (Rohrbach and Phillips, 1990), and
which is sometimes referred to as soft rot or stem-end rot, depending on
the mode of infection. The fungus survives in plant debris in the soil in
the form of thick-walled chlamydospores. Infective asexual conidia are
splashed onto the fruit by rain. The sexual state (perithecia with
http://arab2000.forumpro.fr