Without the treatment of epicatechin and catechin,
green and ripe coffee berries inoculated with
C. kahawae Z1 showed normal expanding necrotic
lesions 4 d after inoculation; ripe coffee berries
inoculated with C. gloeosporioides Ch27 produced
visible symptoms at 3–5 d after inoculation.
When berries were inoculated with conidial suspension
containing 1.2 and 2.3 mg epicatechin or
catechin/ml, the percentage of infection of fungus
C. kahawae Z1 on both green and ripe berries and
of fungus C. gloeosporioides Ch27 on ripe coffee
berries was less than 30% of the control (Fig. 1).
No significant differences in the percentage of
infections were observed between the two concentrations.
In addition, the development of
symptoms on the berries induced by conidia
treated with epicatechin or catechin was much
slower. Some lesions did not develop further;
others developed slowly but never reached the
usual size of the non-treated control (Fig. 2). No
lesions appeared when the green berries were
inoculated with conidial suspensions containing
above 3 mg epicatechin or catechin/ml. Delay in
the appearance of normal lesions might be due to
the lower number of penetrating hyphae resulting
from the small number of appresoria that maintained
viability and/or that could recover viability
slowly under the treatment.