© Benaki Phytopathological Institute
Abstracts - 16th Hellenic Phytopathological Congress
69
equally effective in controlling Verticillium
wilt. However seed coating treatment was
ineffective in the case of K165, but F2 treat-
ment partially reduced disease severity. The
differences in the efficacy of the different
biocontrol preparations to control Verticil-
lium wilt reflected the observed differenc-
es in the size of the BCA populations be-
tween the treatments of 1%, 5%, 10%, 20%
and seed coating.
Spread of hypovirulent strains of the fungus
Cryphonectria parasitica
after biological control of chestnut blight in the Region of Epirus
G.T. T
ZIROS
, C. P
ERLEROU
, E. T
OPALIDOU
, V. C
HRISTOPOULOS
and S. D
IAMANDIS
Hellenic Agricultural Organization ‘’Demeter’’ (Ex NAGREF), Forest Research
Institute, GR-570 06 Vassilika, Thessaloniki, Greece
Chestnut blight, a bark disease caused by
the fungus
Cryphonectria parasitica
, was first
reported in Greece, Mount Pelio, in 1963. Un-
til 2002 it was spread all over the mainland
country where chestnut is cultivated, while
in 2006 it was recorded in the islands of Les-
vos and Crete. It is known that the above as-
comycete may be infected by dsRNA virus-
es called
Cryphonectria
hypoviruses (CHVs),
a fact that reduces fungal virulence to levels
ranging from avirulence to near-virulence.
Such infected strains with proved reduction
in their virulence termed as hypovirulent
(hv) were used for the biological control of
the pathogen in the period 2007-2009 in the
Region of Epirus (Prefectures of Arta and Io-
annina). Two years after the end of artificial
inoculations, samples from cankers were
randomly selected from three round plots
(orchards) in Arta and from six plots in cop-
pice forest in Ioannina. The growth and the
characterization of the strains yielded into
virulent and hypovirulent were carried out
on PDA medium according to morphologi-
cal features. In Arta 34.9 - 53.1% of the total
cankers yielded hv strains, while in Ioanni-
na the percentage fluctuated between 39.2
and 68.5%. Furthermore, 35.9 - 61.85% of the
non inoculated cankers sampled yielded hv
strains in the Prefecture of Ioannina, while
the percentage was 32.3- 48.8% for Arta. The
results show that, two years after the end of
artificial inoculations, introduced hypovi-
lence was successful in all treated areas as
hypovirulent strains of the fungus have set-
tled in orchards as well as in coppice stands
and began as well spreading to non inocu-
lated cankers.
Determination of the optimal retention time for sclerotia in soil paste
for the isolation of
Sclerotinia sclerotiorum
mycoparasites. A proposed
method for the eradication of nematodes and mites.
F.A. T
SAPIKOUNIS
*
Department of Biology, University of Patras, GR-265 00 Rio, Patra, Greece. *Present
address: Agiou Nikolaou 48, GR-270 52 Varda, Ilia, Greece
In order to determine the optimal time of
sclerotia retention in soil paste, seven dif-
ferent retention times, each using four rep-
licate s and 40 sclerotia in total were exam-
ined. The sclerotia were placed in the soil
paste and incubated at 25
0
C in the dark with
collection and disinfection taking place eve-
ry five days, beginning at 5 days for the first
treatment and ending at 35 for the seventh.
For all treatments soil from the same field
was used. Subsequently the sclerotia were
disinfected and placed for 24 or 48 hours in
a environment with 100% relative humidity.
After 35, 30, 25, 20, 15, 10 and 5 days in soil,
the proportion of sclerotia in a good condi-
tion (not dissolved during the process of de-
contamination) was 0, 10%, 17%, 20%, 80%,
97.5% and 100%. The optimal retention
