© Benaki Phytopathological Institute
Fusarium subglutinans
against Western Flower thrips
69
Discussion
Previous studies focused on efficacy of
F
.
subglutinans
on several aphid species (Erkiliç
et al
., 1999; Satar
et al
., 2000; Satar and Koç,
2004; Arici
et al
., 2012). Satar
et al
. (2000) re-
ported that 1x10
7
spores/ml concentration
of
F
.
subglutinans
caused 16% and 45.5%
deaths on
A. gossypii
(Hemiptera: Aphidi-
dae) which fed on cotton and eggplant, re-
spectively, and 12.9% on
Myzus persicae
(Hemiptera: Aphididae) which fed on egg-
plant.
In the present study, 1x10
4
-1x10
8
spores/
ml concentrations of
F
.
subglutinans
12A
had similar efficacy (in terms of mortali-
ty) against the thrips
F. occidentallis
but the
1x10
6
spores/ml concentration was found
appropriate for mycosis. Lethal effect of
F
.
subglutinans
could be expected to vary on
different host plants, pest species and differ-
ent life stages of pests. The mortality rate of
the 10
6
spores/ml concentration of
F
.
subglu-
tinans
12A was 58% on the 2
nd
instar nymphs
of the thrips.
The concentration 10
6
spores/
ml of
F
.
subglutinans
was the most effective
on
A
.
gossypii
and
A
.
fabae
in studies by Satar
and Koç (2004) and; Arici
et al
. (2012).
Other fungi recorded to have biocid-
al effect on
F
.
occidentalis
include
Beauver-
ia bassiana
,
Lecanicillium
(
Verticilium
)
lecanii
(Ascomycota: Cordycipitaceae) and
Metarhi-
zium anisopliae
(Clavicipitaceae) (Jacobson
et al
., 2001; Ludwig and Oetting, 2002; Ma-
niania
et al
., 2002). Whereas recorded mor-
tality rates were 20-70 % for
L
.
lecanii
, these
were 93.5-100% for
M
.
anisopliae
on differ-
ent life stages of
F
.
occidentalis
(Vestergaard
et al
., 1995; Gouli
et al
., 2009)
.
Several efficacy
studies of different spore concentrations of
B
.
bassiana
showed that this fungus caused
67-96% deaths on pre adult stages of
F
.
occi-
dentalis
. In addition 1x10
7
conidia/mlwas the
most effective spore concentration in sever-
al other studies Gouli
et al
., 2009; Gao
et al
.,
2012; Wu
et al
., 2014), However these studies
have no data on mycosis rates of the pest.
In conclusion,
F
.
subglutinans
12A had a
lethal effect on
F
.
occidentalis
and the fungus
was found more effective on adults than the
2
nd
instar nymphs. Developing hyphae and
spores of entomopathogenic fungi provide
Figure 2.
Mean number of 2
nd
instar nymphs of
Frankliniella occidentalis
after treatment (dipping) with 1x10
6
spores/ml
concentration of
Fusarium subglutinans
12A.
