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

FREEDOM PALESTINE FREEDOM PALESTINE FREEDOM PALESTINE
Biological Control 229
Application of the two epiphytic fungal antagonists, A, pullulans and
Epicoccum purpurescens, obtained from healthy peach blossoms, to
cherry blossoms, reduced the number of quiescent infections of Monilinia
fructicola in green cherries (Wittig et al., 1997). Selected strains of A.
pullulans, Rhodotorula glutinis and Bacillus subtilis, isolated from leaf
and fruit surfaces, were found to suppress postharvest decay
development by P. expansum, B, cinerea and Pezicula malicorticis, when
applied in combined mixtures to apple trees in the field (Leibinger et al.,
1997). A combination of two strains of A pullulans and one strain of JR.
glutinis suppressed rotting of apples to the same extent as the commonly
used fungicide euparen. It was further noted that applications before
harvest are also of great interest because European regulations
governing integrated pest management do not allow postharvest
treatments of apples (Leibinger et al., 1997). Application of cell
suspensions of the yeasts R, glutinis and two Cryptococcus species to
pear fruits in the field, 3 weeks prior to harvest, was found to maintain
high population levels through harvest. The three yeast species provided
significant postharvest control of blue mold (P. expansum), gray mold (JB.
cinerea) and side rots (Cladosporium herbarum, Alternaria alternata and
Phialophora malorum). The most consistent decay control, however, was
provided by Cryptococcus infirmo-miniatus, although the decay incidence
and type of decay observed varied among years and among pear cultivars
(Benbow and Sugar, 1999).
A reduction in pathogen development following postharvest
application of the antagonist has been recorded for pineapple fruits on
which field sprays with non-pathogenic strains of Penicillium
funiculosum suppressed decay caused by pathogenic strains of this
fungus during storage (Lim and Rohrbach, 1980).
A significant reduction in the incidence of green mold rot {Penicillium
digitatum) in stored grapefruits was also achieved by spraying the fruits,
prior to picking, with yeast cells of Pichia guilliermondii (Droby et al.,
1992). Such a treatment seems to reduce the potential inoculum level of
the pathogenic spores which are naturally located on the fruit prior to
harvesting.
Postharvest application
Postharvest application of the antagonist is often done by postharvest
sprays or by bringing wounds on the fruit peel in contact with it.
Spraying with suspensions of Trichoderma harzianum, T. viride,
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