International Journal of Horticulture 2015, Vol. 5, No.16, 1
-
6
4
previously treated host eggs of
S. cerealella
by
T.
chilonis
. Moreover, Khan et al. (2015a)
investigated that fipronil induces approximately
100% mortality of adult
T. pretiosum
at field dose
within 24 hours of exposure to treated cotton leaves.
Fipronil is a broad-spectrum insecticide that belongs
to the family phenylpyrazole, and has been in
commercial use since 1993 (Tingle et al., 2003). It
prevents the passage of chloride ions through the GABA
(gamma aminobutyric acid) receptor and glutamate gated
Table 1 Percentage emergence (mean ± SE) of
T. chilonis
from eggs of
Sitotroga cerealella
Olivier treated with fipronil when
parasitoids were at larval and pupal stages, and means comparison based on Tukey HSD, P = 0.05 or 5%
S.
no
Stage
Doses (mean ±SE) and toxicity ranking
Cont
0.4x
C
0.2x
C 0.08x
C
0.04x
C
0.02x
C
mean
1
Larvae
0.00 ±0.00
c
4
0.00 ±
0.0 c
4
6.70±
2.72 bc
3
6.33
±2.21 bc
3
25.61±
4.12 b
2
18.68
73.4 ±
5.75 a
2
Pupae
3.40±1.71
d
3
29.05±2.
63 c
2
39.65±
5.39
bc
2
61.81±
7.64
ab
1
73.51±5.
00 a
1
47.39
73.53
±5.23 a
ANOVA for emergence based on larval test
df
f
p
remark
Dose
5
39.47
< 0.0001
highly sig
ANOVA for emergence based on pupal test
df
f
p
remark
Dose
5
25.92
< 0.0001
highly sig
Means followed by the same letter within a column/among columns are not significantly different (Tukey‘s HSD, p > 0.05).
―C‖ stand for toxicity categories of IOBC/WPRS: 1= harmless (E < 30%); 2 = slight harmful (30 ≤ E ≤ 79%); 3 = moderately
harmful (79 < E ≤ 99%); 4 = harmful (> 99 %).
Table 2 Parasitism (mean ±SE) of previously treated eggs of
Sitotroga cerealella
Olivier with fipronil by
T. chilonis
, and means
comparison based on Tukey HSD, P = 0.05 or 5%
S.no
Doses (mean ±SE) and toxicity ranking
Control
0.2x
C
0.08x
C
0.04x
C
0.02x
C
mean
1
5 ±1.39 ab
2
7 ±1.80 ab
2
8.5±1.42 a
2
10.7±1.31 a
1
7.2
12.2 ±2.02 a
ANOVA for parasitism
df
f
p
remark
Dose
5
5.89
< 0.001
sig
Means followed by the same letter within a column/among columns are not significantly different (Tukey‘s HSD, p > 0.05). ―C‖
stand for toxicity categories of IOBC/WPRS
chloride (GluCl) channels, components of the central
nervous system (Colliot et al., 1992; Cole et al., 1993;
Tingle et al., 2003), and in such way interferes with
the insect central nervous system, which led to
hyperexcitation of nerves and muscles of insects. It
is commonly used in rice and sugarcane to control
stem borers at field recommended concentration
of 480 ml/acre, and is available with trade name
―Regent‖ 5% SC in Pakistan.
The recommended rate of fipronil (4%) was very
effective against
Hieroglyphus
spp., in rice, maize,
