The investigation registered the activity of three predatory insects viz., green lacewing (Chrysoperla sp.), coccinellids (Coccinella transversalis, Cheilomenes sexmaculata, Illeis cincta), syrphids and one predatory spider (Oxyopes sp.). The observations recorded on population of Chrysoperla sp. per square meter area in wheat crop at different intervals are presented in Table 1. The pooled mean of chrysopid population at 5, 10 and 15 Days After Spraying (DAS) confirmed that the seed treatment with thiamethoxam 30 FS @ 5 ml/kg seed (T1) recorded maximum population of 1.20 followed by soil application of carbofuran 3G @ 30 kg/ha (T2) (1.17) besides untreated check (1.39). Whereas, soil application of carbofuran 3G @ 30 kg/ha followed by a spray of cypermethrin 10 EC @ 0.5 ml/l recorded least density (0.22) of chrysopids and found on par with seed treatment with thiamethoxam 30 FS @ 5 ml/l along with a spray of cypermethrin 10 EC @ 0.5 ml/l (0.25). During the investigation, we have recorded three coccinellid predators viz., Coccinella transversalis, Cheilomenes sexmaculata, and Illeis cincta (fungal predator) in the field. As per the data presented in Table 2, the pooled mean of three intervals in different treatments confirmed that the untreated control (UTC) reported maximum coccinellid population of 1.51 per meter square area, followed by T1 (1.40) and T2 (1.37). Whereas, the least population was noticed in T8 (0.24) which was closely followed by T7 (0.28).
Table 1
Impact of insecticidal treatments on Chrysoperla sp. population in wheat
Tr. No.
|
Treatments
|
Dosage
|
Number of Chrysoperla/m2
|
1 DBS
|
5 DAS
|
10 DAS
|
15 DAS
|
Mean
|
1
|
Seed treatment with Thiamethoxam 30 FS
|
5 ml/kg
|
0.89
(1.18)a
|
0.94
(1.20)a
|
1.25
(1.32)ab
|
1.41
(1.38)ab
|
1.20
|
2
|
Soil application of Carbofuran 3G
|
30 kg/ha
|
0.81
(1.14)a
|
0.92
(1.19)a
|
1.21
(1.31)ab
|
1.39
(1.37)abc
|
1.17
|
3
|
T1 + One spray of Nimbecidine 1500 ppm
|
5 ml/kg +
3 ml/l
|
0.83
(1.15)a
|
0.71
(1.10)ab
|
0.79
(1.14)ab
|
0.98
(1.22)bcd
|
0.83
|
4
|
T2 + One spray of Nimbecidine 1500 ppm
|
30 kg/ha +
3 ml/l
|
0.78
(1.13)a
|
0.75
(1.12)ab
|
0.76
(1.12)ab
|
0.92
(1.19)cd
|
0.81
|
5
|
T1 + One spray of Emamectin benzoate 5 SG
|
5 ml/kg +
0.2 g/l
|
0.81
(1.14)a
|
0.45
(0.97)bc
|
0.51
(1.00)ab
|
0.76
(1.12)d
|
0.57
|
6
|
T2 + One spray of Emamectin benzoate 5 SG
|
30 kg/ha +
0.2 g/l
|
0.75
(1.12)a
|
0.41
(0.95)bc
|
0.49
(0.99)ab
|
0.74
(1.11)d
|
0.55
|
7
|
T1 + One spray of Cypermethrin 10 EC
|
5 ml/kg +
0.5 ml/l
|
0.86
(1.17)a
|
0.23
(0.85)c
|
0.25
(0.87)b
|
0.28
(0.88)e
|
0.25
|
8
|
T2 + One spray of Cypermethrin 10 EC
|
30 kg/ha +
0.5 ml/l
|
0.79
(1.14)a
|
0.19
(0.83)c
|
0.22
(0.85)b
|
0.24
(0.86)e
|
0.22
|
9
|
Untreated check (UTC)
|
-
|
0.91
(1.19)a
|
0.95
(1.20)a
|
1.54
(1.43)a
|
1.69
(1.48)a
|
1.39
|
|
S. Em±
|
0.08
|
0.06
|
0.06
|
0.07
|
-
|
CD at 5%
|
NS
|
0.18
|
0.18
|
0.20
|
-
|
CV (%)
|
12.92
|
9.76
|
9.64
|
9.82
|
-
|
DBS: Day Before Spraying |
DAS: Days After Spraying |
NS: Non-Significant |
*Figures in parentheses are √x+0.5 transformed values
Means followed by same alphabet in a column do not differ significantly (0.05) by DMRT
Table 2
Impact of insecticidal treatments on coccinellid population in wheat
Tr. No.
|
Treatments
|
Dosage
|
Number of coccinellids/m2
|
1 DBS
|
5 DAS
|
10 DAS
|
15 DAS
|
Mean
|
1
|
Seed treatment with Thiamethoxam 30 FS
|
5 ml/kg
|
0.98
(1.22)a
|
0.94
(1.20)a
|
1.40
(1.38)a
|
1.86
(1.54)a
|
1.40
|
2
|
Soil application of Carbofuran 3G
|
30 kg/ha
|
0.81
(1.14)a
|
0.95
(1.20)a
|
1.36
(1.36)a
|
1.81
(1.52)a
|
1.37
|
3
|
T1 + One spray of Nimbecidine 1500 ppm
|
5 ml/kg +
3 ml/l
|
0.87
(1.17)a
|
0.65
(1.07)ab
|
0.96
(1.21)ab
|
1.28
(1.33)b
|
0.96
|
4
|
T2 + One spray of Nimbecidine 1500 ppm
|
30 kg/ha +
3 ml/l
|
0.72
(1.10)a
|
0.63
(1.06)ab
|
0.94
(1.20)ab
|
1.23
(1.32)b
|
0.93
|
5
|
T1 + One spray of Emamectin benzoate 5 SG
|
5 ml/kg +
0.2 g/l
|
0.86
(1.17)a
|
0.34
(0.92)bc
|
0.46
(0.98)bc
|
0.54
(1.02)c
|
0.45
|
6
|
T2 + One spray of Emamectin benzoate 5 SG
|
30 kg/ha +
0.2 g/l
|
0.83
(1.15)a
|
0.31
(0.90)bc
|
0.43
(0.96)bc
|
0.51
(1.00)c
|
0.42
|
7
|
T1 + One spray of Cypermethrin 10 EC
|
5 ml/kg +
0.5 ml/l
|
0.81
(1.14)a
|
0.22
(0.85)c
|
0.28
(0.88)c
|
0.33
(0.91)c
|
0.28
|
8
|
T2 + One spray of Cypermethrin 10 EC
|
30 kg/ha +
0.5 ml/l
|
0.79
(1.14)a
|
0.19
(0.83)c
|
0.23
(0.85)c
|
0.29
(0.89)c
|
0.24
|
9
|
Untreated check (UTC)
|
-
|
0.99
(1.22)a
|
0.95
(1.20)a
|
1.49
(1.41)a
|
2.10
(1.61)a
|
1.51
|
|
S. Em±
|
0.07
|
0.06
|
0.08
|
0.07
|
-
|
CD at 5%
|
NS
|
0.19
|
0.23
|
0.20
|
-
|
CV (%)
|
10.27
|
10.70
|
11.90
|
9.63
|
-
|
DBS: Day Before Spraying |
DAS: Days After Spraying |
NS: Non-Significant |
*Figures in parentheses are √x+0.5 transformed values
Means followed by same alphabet in a column do not differ significantly (0.05) by DMRT
The similar trend was also observed in abundance of syrphid population (Table 3) where, the pooled mean population of 5, 10 and 15 DAS ranged from 0.14 to 0.81 per meter square area with T1 (0.73) being superior over other insecticidal treatments besides untreated check (0.81) and closely followed by T2 (0.70). During the experiment, we have also looked over the diversity of spider population and registered one predatory spider, Oxyopes sp. in the experimental plots. The pooled mean of three intervals in different treatments also confirmed the trend, where the peak spider population was recorded in T1 (0.67) and T2 (0.62) where they found numerically on par with untreated check (0.78). The lowest density of 0.12 observed from T8 (Table 4). In overall observations, the population of all the predators were present to a greater extent within untreated plot compared with the treated ones.
Table 3
Impact of insecticidal treatments on syrphid population in wheat
Tr. No.
|
Treatments
|
Dosage
|
Number of syrphids/m2
|
1 DBS
|
5 DAS
|
10 DAS
|
15 DAS
|
Mean
|
1
|
Seed treatment with Thiamethoxam 30 FS
|
5 ml/kg
|
0.51
(1.00)a
|
0.58
(1.04)ab
|
0.75
(1.12)a
|
0.86
(1.17)ab
|
0.73
|
2
|
Soil application of Carbofuran 3G
|
30 kg/ha
|
0.43
(0.96)a
|
0.56
(1.03)ab
|
0.71
(1.10)a
|
0.83
(1.15)abc
|
0.70
|
3
|
T1 + One spray of Nimbecidine 1500 ppm
|
5 ml/kg +
3 ml/l
|
0.48
(0.99)a
|
0.42
(0.96)abc
|
0.62
(1.06)ab
|
0.66
(1.08)abc
|
0.57
|
4
|
T2 + One spray of Nimbecidine 1500 ppm
|
30 kg/ha +
3 ml/l
|
0.43
(0.96)a
|
0.40
(0.95)abc
|
0.63
(1.06)ab
|
0.64
(1.07)abc
|
0.56
|
5
|
T1 + One spray of Emamectin benzoate 5 SG
|
5 ml/kg +
0.2 g/l
|
0.49
(0.99)a
|
0.25
(0.87)abc
|
0.32
(0.91)bc
|
0.36
(0.93)abc
|
0.31
|
6
|
T2 + One spray of Emamectin benzoate 5 SG
|
30 kg/ha +
0.2 g/l
|
0.45
(0.97)a
|
0.24
(0.86)bc
|
0.29
(0.89)bc
|
0.32
(0.91)abc
|
0.28
|
7
|
T1 + One spray of Cypermethrin 10 EC
|
5 ml/kg +
0.5 ml/l
|
0.49
(0.99)a
|
0.11
(0.78)c
|
0.18
(0.82)c
|
0.21
(0.84)bc
|
0.17
|
8
|
T2 + One spray of Cypermethrin 10 EC
|
30 kg/ha +
0.5 ml/l
|
0.42
(0.96)a
|
0.09
(0.77)c
|
0.15
(0.81)c
|
0.17
(0.82)c
|
0.14
|
9
|
Untreated check (UTC)
|
-
|
0.52
(1.01)a
|
0.62
(1.06)a
|
0.79
(1.14)a
|
1.01
(1.23)a
|
0.81
|
|
S. Em±
|
0.06
|
0.07
|
0.07
|
0.09
|
-
|
CD at 5%
|
NS
|
0.21
|
0.23
|
0.28
|
-
|
CV (%)
|
9.37
|
10.49
|
10.64
|
12.92
|
-
|
DBS: Day Before Spraying |
DAS: Days After Spraying |
NS: Non-Significant |
*Figures in parentheses are √x+0.5 transformed values
Means followed by same alphabet in a column do not differ significantly (0.05) by DMRT
Table 4
Impact of insecticidal treatments on spider population in wheat
Tr. No.
|
Treatments
|
Dosage
|
Number of spiders/m2
|
1 DBS
|
5 DAS
|
10 DAS
|
15 DAS
|
Mean
|
1
|
Seed treatment with Thiamethoxam 30 FS
|
5 ml/kg
|
0.37
(0.93)a
|
0.51
(1.00)ab
|
0.58
(1.04)ab
|
0.92
(1.19)ab
|
0.67
|
2
|
Soil application of Carbofuran 3G
|
30 kg/ha
|
0.28
(0.88)a
|
0.48
(0.99)ab
|
0.51
(1.00)abc
|
0.87
(1.17)abc
|
0.62
|
3
|
T1 + One spray of Nimbecidine 1500 ppm
|
5 ml/kg +
3 ml/l
|
0.40
(0.95)a
|
0.26
(0.87)abc
|
0.29
(0.89)bcd
|
0.54
(1.02)bcd
|
0.36
|
4
|
T2 + One spray of Nimbecidine 1500 ppm
|
30 kg/ha +
3 ml/l
|
0.34
(0.92)a
|
0.24
(0.86)abc
|
0.28
(0.88)bcd
|
0.51
(1.00)cd
|
0.34
|
5
|
T1 + One spray of Emamectin benzoate 5 SG
|
5 ml/kg +
0.2 g/l
|
0.45
(0.97)a
|
0.19
(0.83)bc
|
0.21
(0.84)cd
|
0.32
(0.91)de
|
0.24
|
6
|
T2 + One spray of Emamectin benzoate 5 SG
|
30 kg/ha +
0.2 g/l
|
0.37
(0.93)a
|
0.17
(0.82)bc
|
0.19
(0.83)cd
|
0.28
(0.88)de
|
0.21
|
7
|
T1 + One spray of Cypermethrin 10 EC
|
5 ml/kg +
0.5 ml/l
|
0.44
(0.97)a
|
0.10
(0.77)c
|
0.14
(0.80)d
|
0.15
(0.81)e
|
0.13
|
8
|
T2 + One spray of Cypermethrin 10 EC
|
30 kg/ha +
0.5 ml/l
|
0.29
(0.89)a
|
0.10
(0.77)c
|
0.12
(0.79)d
|
0.13
(0.79)e
|
0.12
|
9
|
Untreated check (UTC)
|
-
|
0.46
(0.98)a
|
0.56
(1.03)a
|
0.75
(1.12)a
|
1.02
(1.23)a
|
0.78
|
|
S. Em±
|
0.06
|
0.06
|
0.06
|
0.06
|
-
|
CD at 5%
|
NS
|
0.19
|
0.17
|
0.18
|
-
|
CV (%)
|
11.68
|
12.51
|
11.01
|
10.17
|
-
|
DBS: Day Before Spraying |
DAS: Days After Spraying |
NS: Non-Significant |
*Figures in parentheses are √x+0.5 transformed values
Means followed by same alphabet in a column do not differ significantly (0.05) by DMRT