IJH-2018v8n17 - page 10

International Journal of Horticulture, 2018, Vol.8, No.17, 197-203
201
Table 3 Effect of Fipronil 80 WG (Regent 80 WG) against grape thrips and on grape yield
Tr.
No
Treatment
Dose/ha
(ml/g)
Dose
(g a.i./ha)
% Protection against
thrips over untreated
check
% decrease in
thrips population
over pre-count
% bunches
showing scab
symptoms
Yield
(kg/vine)
First
season
Second
season
First
season
Second
season
First
season
Second
season
First
season
Second
season
T
1
Fipronil 80 WG
(Regent 80 WG)
50
40
94.5
91.8
94.7 92.2
12.1
(20.3)
a
14.1
(20.1)
a
9.7
a
10.9
a
T
2
Fipronil 80 WG
(Regent 80 WG)
62.5 50
95.6
94.5
96.0 94.8
10.2
(18.6)
a
12.4
(20.5)
a
10.2
a
11.6
a
T
3
Fipronil 5 SC
(Regent 5 SC)
800
40
90.1
88.2
91.6 89.3
12.4
(20.6)
a
14.6
(22.5)
a
9.5
a
10.5
a
T
4
Spinosad 45 SC
(Tracer 45 SC)
187.5 84.375 84.6
86.4
85.4 86.7
13.5
(21.5)
a
15.8
(23.4)
a
9.8
a
10.7
a
T
5
Imidacloprid 200 SL
(Confidor 200 SL)
225
45
86.8
83.6
88.6 85.1
12.6
(20.7)
a
14.8
(22.5)
a
9.6
a
10.8
a
T
6
Monocrotophos 36
WSC-Dimethoate
30 EC (RPP)
1000
1700
360
521
82.4
82.7
83.8 84.4
20.0
(26.5)
b
22.4
(28.2)
b
9.8
a
10.5
a
T
7
Untreated check
(Water spray)
-
-
-
-
10.8 12.7
83.0
(65.8)
c
86.8
(68.8)
c
7.5
b
8.6
b
S.Em. ±
-
-
-
-
-
-
7.7
1.1
0.4 0.6
C.D. (0.05)
-
-
-
-
-
-
3.8
3.5
1.4 1.9
C.V. (%)
-
-
-
-
-
-
1.2
6.6
8.0 10.1
Note: T
1
to T
5
- Two sprays at 10 days interval, T
6
- Monocrotophos (1
st
Spray) followed by Dimethoate (2
nd
Spray) at 10 days interval;
RPP= Recommended package of practice; In the vertical columns means followed by same letters are not different
statistically (P= 0.05) by DMRT; Figures in the parentheses are arcsin transformed values
All the insecticidal treatments reduced more than 80 per cent of thrips population over pre-count. Two sprays of
Fipronil 80 WG @ 50 g a.i./ha caused highest reduction in thrips population (96.0 and 94.8% during first and
second season, respectively) over pre-count followed by Fipronil 80 WG @ 40 g a.i./ha, Fipronil 5 SC @ 40 g
a.i./ha, Imidacloprid 200 SL @ 45 g a.i./ha, Spinosad 45 SC @ 84.375 g a.i./ha and Standard check
(Monocrotophos 36 WSC @ 360 g a.i./ha followed by Dimethoate 30 EC @ 521 g a.i./ha) with 94.7, 91.6, 88.6,
85.4 and 83.8, and 92.2, 89.3, 85.1, 86.7 and 84.4 per cent reduction in thrips population during first and second
season, respectively (Table 3). The results are in line with Niranjana (2008) who reported that Fipronil 80
WG (50 g a.i./ha) followed by spinosad 2.5 SC (84.375 g a.i./ha) and imidacloprid 17.8 EC (45 g a.i./ha)
proved effective in the control of S. dorsalis in grapes. Bangosavi (2009) reported that, two sprays of spinosad
@ 0.013,5 per cent were found highly effective with maximum reduction of grape thrips population.
The insecticidal treatments viz., Fipronil 80 WG @ 50 g a.i./ha and 40 g a.i./ha, Fipronil 5 SC @ 40 g a.i./ha,
Imidacloprid 200 SL @ 45 g a.i./ha and Spinosad 45 SC @ 84.375 g a.i./ha recorded lowest percentage of
bunches having scab symptoms (10.2, 12.1, 12.4, 12.6 and 13.5% during first season and 12.4, 14.2, 14.6, 14.8
and 15.8%, respectively during second season) and were on par with each other, while Standard check
(Monocrotophos 36 WSC @ 360 g a.i./ha followed by Dimethoate 30 EC @ 521 g a.i./ha) was inferior to them
with 20 and 22.4 per cent bunches having scab symptoms during first and second season, respectively (Table 3).
Prema et al. (2016) reported that fipronil 80 WG at 100, 80, 60, 50 and 40 g a.i./ha reduced more than 80 per cent
thrips damage to grape berries, thus recorded significantly minimum fruit damage. Bangosavi (2009) reported that
minimum per cent scarred berries and higher yield were found in spinosad @ 0.013,5 per cent at harvest in grapes.
Fipronil 80 WG @ 50 g a.i./ha recorded highest yield of 10.2 and 11.6 kg/vine during first and second year,
respectively and did not differ statistically from Fipronil 80 WG @ 40 g a.i./ha, Spinosad 45 SC @ 84.375 g
a.i./ha, Standard check (Monocrotophos 36 WSC @ 360 g a.i./ha followed by Dimethoate 30 EC @ 521 g a.i./ha),
1,2,3,4,5,6,7,8,9 11,12,13,14
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