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

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Postharvest Disease Summary 307
D. Penicillium expansum Link.
This fungus is a common postharvest pathogen of stone fruits in all
producing areas, but can attack only injured or over-mature fruit. Fruits
that have been heat treated to reduce incipient infections of brown rot
are also sensitive to Penicillium infection (Smith, W.L. and Anderson,
1975). During storage, conidiophores bearing blue-green conidia are
produced in coremia, sometimes arranged in concentric circles around
the point of infection. A white edge remains around the rotten area as it
develops (Hall and Scott, 1989b). The infected tissue is moist and
characterized by a musty odor. Since the growth of Penicillium is greatly
reduced at low temperatures, rapid pre-cooling and cold storage
markedly suppress its development.
E. Colletotrichum gloeosporioides (Penz.) Sacc, [perfect state:
Glomerella cingulata (Stonem.) Spauld & v. Schrenk]
This fungus is the causal agent of anthracnose. Some strains can
exhibit the sexual state (perithecia with ascospores), but infection is
generally initiated by the asexual spores (conidia produced in acervuli).
The fungus penetrates the fruit mainly via wounds caused by twig
abrasion while on the tree (Rittenburg and Hendrix, 1983), and disease
symptoms may appear in the orchard. If infection occurs shortly before
harvest and the disease cannot yet be detected in the packinghouse, it
will develop later in storage. During harvesting and handling operations,
infections may take place through wounds and can be spread from
diseased fruit to sound fruit by contact.
Lesions are firm and sometimes tend to coalesce and cover the fruit
(Ramsey et al., 1951). However, almost no progress takes place below
5°C. Under humid conditions, a mycelium-bearing salmon-pink mass of
spores, ready to initiate new infections, is developed.
F. Mucor piriformis Fischer
This fungus is generally considered a disease of minor importance in
stone fruits. However, following its isolation from several stone fruits,
mainly peaches and nectarines, it has been regarded as a threat since, in
contrast to Rhizopus, this pathogen can develop in cold storage even at
0°C (Smith, W.L. et al., 1979), and is not controlled by available fungicide
treatments (Eckert and Ogawa, 1988).
Infection takes place when the asexual spores (sporangiospores within
sporangia) penetrate wounded fruits and cause a soft, watery rot. During
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