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

FREEDOM PALESTINE FREEDOM PALESTINE FREEDOM PALESTINE
176 Postharvest Diseases of Fruits and Vegetables
et al., 1971). The antifungal action is thought to be due to the
interference with the cell-wall-forming enzymes.
Studsdng the potential of various sugar analogs as antifungal agents
for decay suppression, El Ghaouth et al. (1995) found that only
2-deoxy-D-glucose was effective in controlling decay in apples inoculated
with JB. cinerea and P. expansum (Table 10), or in peaches inoculated
with M fructicola. This compound inhibited in vitro radial growth of
P. expansum, B, cinerea, M. fructicola and even K stolonifer, which is
known to be insensitive to most postharvest fungicides. At 0.1% it
induced severe morphological alterations in the tested fungi, suggesting
that growth inhibition is the result of direct antifungal properties of the
sugar analog. It was also suggested that this sugar analog could serve as
a useful additive to a biological control method, provided that the
antagonist is resistant to its inhibitory action (El Ghaouth et al., 1995).
TABLE 10
Effect of sugar analogs on gray mold and blue mold of apples
after 7 days at 24°Ci
Treatment^
Control
Glucose
Mannose
L-sorbose
Rafinose
Deoxy-D-ribose
2-deoxy-D-glucose
LSDos
1 Reproduced from El Ghaouth et al. (1995) with permission of the
American Phytopathological Society.
2 Wounded fruits treated with 50 |LI1 of different sugar analogs or sterile
water and 30 min later were inoculated with 30 \xl conidial
suspensions oiBotrytis cinerea or Penicillium expansum.
3 After 14 days' incubation.
Infected fruit (%)
Botrytis cinerea Penicillium
expansum
100
100
100
100
97.0
95.2
94.3
93.1
98.1
100
99.3
96.4
0 (21.3)3
0 (22.4)3
4.9
2.9
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