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

FREEDOM PALESTINE FREEDOM PALESTINE FREEDOM PALESTINE
Postharvest Disease Summary 295
mycotoxin, and the amounts produced were considerably reduced, as
compared with production in air. Sommer et al. (1974) found that two
strains of P. expansum produced patuHn in Golden Delicious apples
stored in a controlled atmosphere containing 7.5% CO2 and 2% O2 at
23°C, although at markedly lower levels than in air. Working with other
P. expansum strains, Paster et al. (1995) found that patulin production
was inhibited in Starking apples stored in an atmosphere of 3% CO2, 2%
O2 at 25°C, although fungal growth was still 70% of that of the control.
Under 3% CO2, 10% O2, patulin production was only slightly reduced.
B. Botrytis cinerea Pers. [perfect state: Botryotinia fuckeliana (de
Bary) Whetzel]
The gray mold rot caused by this fungus can cause heavy losses of
pome fruits, particularly pears. The fungus survives as sclerotia in the
soil and on plant debris, and under favorable conditions asexual spores
(conidia) are formed. Under wet conditions the conidia may infect dying
blossoms (Combrink et al., 1983) and remain quiescent in the flower
parts (DeKock and Holz, 1991). Fruit infection occurs later, after renewal
of the pathogen growth during storage and marketing. B. cinerea can
infect the fruit through wounds incurred during harvesting and
handling, or directly via skin breaks (Spotts and Peters, 1982a). In fact,
the resistance of various apple cultivars to infection by B, cinerea and
other wound pathogens has recently been related to the force required to
break the fruit skin (Spotts et al., 1999).
Lesions are dry and firm at first, but become soft as the rot advances.
Under humid conditions, abundant gray-brown conidia are produced.
Sclerotia may also be formed on well advanced lesions. The fungus
spreads very readily during storage by contact between infected and
sound fruit, forming 'nests* of decaying fruit. This type of infection
markedly increases the infection rate in storage (Edney, 1978). In
addition, J5. cinerea may penetrate apple fruits via the sinus between the
calyx and the core cavity, in apple cultivars characterized by open
sinuses, resulting in core rot (Spotts et al., 1988).
C. Monilinia spp.
Monilinia rot may be incited by three species of Monilinia: Monilinia
fructigena (Aderh. & Ruhl.) Honey, which is widespread in Europe, Asia
and South America, but is uncommon in North America; M fructicola
(Wint.) Honey, which occurs in North and South America, South Africa,
Japan, Australia and New Zealand; and Monilinia laxa (Aderh. & Ruhl.)
http://arab2000.forumpro.fr