© Benaki Phytopathological Institute
Fusarium subglutinans
against Western Flower thrips
67
nus of the Plyla Ascomycota and Zygomy-
cota (Samson
et al
., 1988; McCoy
et al
., 1988;
Gillespie and Moorhouse, 1989). A consider-
able number of these species belong to the
genera
Beauveria, Entomophthora, Metarhi-
zium, Neozygites, Nomuraea
and
Lecanicil-
lium
(Desphande, 1999; Shadid
et al
., 2012).
Although
Fusarium
spp. (Ascomycota: Nec-
triaceae) cause diseases in a number of ec-
onomically important plants, the species
Fusarium subglutinans
isolated from aphids
has entomopathogenic action on arthro-
pods (Gerin, 1998; Erkiliç
et al
., 1999; Satar
et
al
., 2000).
The aim of this study was to determine
the insecticidal effect of three different
spore concentrations (1x10
4
, 1x10
6
and 1x10
8
spores/ml) of
F
.
subglutinans
12A on adult fe-
males of
F
.
occidentalis.
The mycosis rate was
recorded on dead individuals
of the thrips.
Additionally, the effect of 1x10
6
spores/ml
concentration was investigated on the 2
nd
instar nymphs of
F
.
occidentalis
.
Materials and Methods
The study plant was pepper (
Capsicum ann-
uum
). Adult females and 2
nd
instar nymphs of
F
.
occidentalis
used in the experiments came
from laboratory colonies kept at 25±1°C, 60-
70% RH and 16:8 h L:D. The isolate 12A of
F
.
subglutinans
from
Aphis gossypii
in Adana-
Karataş, Turkey was used for making suspen-
sions of the fungus.
In the study, spore concentrations of
1x10
4
, 1x10
6
and 1x10
8
spores/ml were pre-
pared by using suspension of
F. subglutin-
ans
12A; they were cultured on potato dex-
trose agar (PDA) and incubated at 25°C for
10 days. Spore concentrations were deter-
mined by using Thoma counting chamber.
In the control, distilled water and Tween 20
(0.1 %) was used.
The experiment was conducted in glass
Petri dishes (9 cm diameter) containing pep-
per leaf discs (5 cmdiameter) on filter papers,
to feed the thrips. In each treatment 10 indi-
viduals, newly emerged adult females or 2
nd
instar nymphs, were used. Before the treat-
ment, thrips were deprived food for 1 hour.
The application method was by dipping for
5 seconds. After treatment the thrips were
transferred by using a moisturized fine paint
brush to the Petri dishes, which were then
covered with parafilm to prevent their pos-
sible escape. The experimental design was
a complete randomized block with five rep-
lications. The Petri dishes were kept in cli-
mate-controlled rooms at 25±1°C, 60-70%
RH, and 16:8 h D:L.
Observations on mortality were made at
24, 48, 72 and 96 hours, and 7 and 9 days af-
ter the dipping. Mycosis observations were
performed between the third and ninth
day of the study. Counting on the 2
nd
instar
nymphs was initiated 24 hours after the dip-
ping and repeated every 24 hours until the
8
th
day of the experiment. Re-isolation was
made at the end of the counting process on
dead individuals.
Statistical Analysis
Square root transformation was applied to
the data of dead individuals. Inverse angle
transformation was applied to the myco-
sis data obtained from dead flesh (body) of
adults. Data were analysed using repeated
measurement analysis of variance in a fac-
torial design (treatment x time). Linear rela-
tion between dead individuals and myco-
sis rates was investigated by calculating the
Pearson correlation coefficient. The Mann-
Whitney ‘U’ test was applied to the data ob-
tained from 2
nd
instar nymphs of
F
.
occiden-
talis
, since the data were non-parametric.
Significance level was P< 0.05.
Results
The mean numbers of dead females of
F. oci-
dentallis
after dipping in solutions of three
different spore concentrations of
F. subgluti-
nans
12A are presented in Table 1. The con-
trol had the lowest mean number of dead fe-
males, which was significantly different from
the other treatments (P<0.05). The mean
