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

FREEDOM PALESTINE FREEDOM PALESTINE FREEDOM PALESTINE
234 Postharvest Diseases of Fruits and Vegetables
the inhibition of Monilinia development within the fruit has been
achieved by the use of both cell-free filtrates of the bacterium and of the
living cells separated from the liquid medium on which they grew,
although autoclaved cells offered no protection (Pusey, 1991). These facts
indicated that living cells of the Bacillus may act on the fruit either by
producing antifungal metabolites or by antagonizing the pathogen in
another way (such as competition for nutrients).
The bacterium, P. cepacia inhibits Botrytis cinerea and Penicillium
expansum growth in apples via the antibiotic compound, pyrrolnitrin
(Janisiewicz and Roitman, 1988). Trials performed with strawberries
have shown that dipping the fruit in p5n:rolnitrin alone delayed gray
mold development by several days, but had no effect on the extent of
decay (Takeda et al., 1990) (Fig. 40).
Experiments with Penicillium digitatum-inoculaied lemon fruit
(Smilanick and Denis-Arrue, 1992) showed that P. cepacia was the most
effective of several Pseudomonas species in controlling green mold decay.
The bacterium developed rapidly in the wound area, did not cause any
2 3 4
Days in storage
Fig. 40. Effect of pyrrolnitrin on rot development on Tribute' strawberry fruit
stored at room temperature. Fruit were dipped in water (O) or 250 mg
pyrrolnitrin/liter (•) and stored at 18°C. Bars indicate LSD, p=0.05. (Reproduced
from Takeda et al., 1990 with permission of the American Society for
Horticultural Science).
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