Helicoverpa larvae plant-1
The data presented in Table 2 reveals that prior to insecticidal treatments, the larval population of
H. armigera before first spray varied from 1.28 larvae plant
-1 (M5) to 1.52 larvae plant
-1 (M4) during
Kharif 2013.
After three days of first spray, there was a sharp decline in the larval population of
Helicoverpa. The lowest population (1.03 larvae plant
-1) was recorded in HaNPV treated plot in M1 while the highest (1.27 larvae plant
-1) in M5. This was followed by Bt treated plot in M2 (1.21 larvae plant
-1) which was at par with Indoxacarb treated plot in M4 (1.20 larvae plant
-1) and Ha-NPV treated plot in M3 (1.10 larvae plant
-1).
Before second spray, the no. of larvae plant
-1 varied from 1.34 (M4) to 1.46 (M5). At 3 DAT second spraying, the lowest population was recorded in Spinosad treated plot (1.17 larvae plant
-1) in M2 and the highest in M5 (1.61 larvae plant
-1), followed by Imidacloprid treated plot in M4 (1.27 larvae plant
-1), NSKE treated plot in M1 (1.25 larvae plant
-1) and Indoxacarb treated plot in M3 (1.19 larvae plant
-1).
Before third spray, the no. of larvae plant
-1 varied from 1.35 (M2) to 1.71 (M5). At 3 DAT third spraying, the lowest larval population was recorded in Indoxacarb treated plot (1.05 larvae plant
-1) in M4 and the highest in M5 (1.79 larvae plant
-1), followed by HaNPV treated plot in M1 (1.23 larvae plant
-1), HaNPV treated plot in M3 (1.17 larvae plant
-1) and Spinosad treated plot in M2 (1.13 larvae plant
-1), which were at par.
The mean larval population of
H. armigera before spray on short duration pigeonpea during
Kharif 2013 varied from 1.34 larvae plant
-1 in M2 to 1.54 larvae plant
-1 40
th to 45
th standard week in M5. This was closely followed by 1.44 larvae plant
-1 in M4, 1.44 larvae plant
-1 in M3 and 1.40 larvae plant
-1 in M1. However, after three sprays in all the modules, it ranged from 1.15 larvae plant
-1 in M3 to 1.61 larvae plant
-1 in M5, followed by 1.25 larvae plant
-1 in M1, 1.18 larvae plant
-1 in M4 and 1.17 larvae plant
-1 in M2. There was significant difference in the mean larval population during the post - treatment period at 3 DAT in M3 and M2, M2 and M4. However, M4 was at par with Ml and M2 was significantly superior over M1. In general, all the modules were significantly superior over M5.
A perusal of the data in the Table 3 reveal that prior to insecticidal treatments, the
H. armigera larvae plant
-1 varied from 1.23 (M2) to 1.45 (M5) during
Kharif 2014.
After three days of first spray, there was a sharp decline in the larval population of
Helicoverpa. The lowest population (0.95 larvae plant
-1) was recorded in HaNPV treated plot in M1 while the highest (1.24 larvae plant
-1) in M5. This was followed by Bt treated plot in M2 (1.15 larvae plant
-1) which was at par with Indoxacarb treated plot in M4 (1.14 larvae plant
-1) and HaNPV treated plot in M3 (1.08 larvae plant
-1).
Before second spray, the no. of larvae plant
-1 varied from 1.27 (M4) to 1.38 (M5). At 3 DAT of second spraying, the lowest population (1.10 larvae plant
-1) was recorded in Spinosad treated plot in M2 and the highest (1.58 larvae plant
-1) in M5. This was followed by Imidacloprid treated plot in M4 (1.22 larvae plant
-1), NSKE treated plot in M1 (1.20 larvae plant
-1) and Indoxacarb treated plot in M3 (1.15 larvae plant
-1).
Before third spray, the no. of larvae plant
-1 ranged from 1.30 (M1) to 1.65 (M5). At 3 DAT of third spraying, the lowest larval population (1.00 larvae plant
-1) was recorded in Indoxacarb treated plot in M4 and the highest (1.73 larvae plant
-1) in M5, followed by HaNPV treated plot in M1 (1.21 larvae plant
-1), HaNPV treated plot in M3 (1.12 larvae plant
-1) and Bt treated plot in M2 (1.17 larvae plant
-1).
The mean larval population of
H. armigera before spray on short duration pigeonpea during
Kharif 2014 varied from 1.29 larvae plant
-1 in M2 to 1.47 larvae plant
-1 in M5. This was closely followed by 1.39 larvae plant
-1 in M4, 1.37 larvae plant
-1 in M3 and 1.34 larvae plant
-1 in M1.
However, after three sprays in all the modules, it ranged from 1.11 larvae plant
-1 in M2 to 1.58 larvae plant
-1 in M5, followed by 1.22 larvae plant
-1 in M1, 1.12 larvae plant
-1 in M4 and 1.12 larvae plant
-1 in M3. There was significant difference in the mean larval population during the post - treatment period at 3 DAT in M2 and M3, M3 and M4. However, M4 was at par with M1 and M3 was significantly superior over M1. In general, all the modules were significantly superior over M5.
These results are in agreement with the findings of Mane
et al., (2013) who also evaluated the efficacy of different insecticides and reported that three days after spraying, HaNPV was equally effective with quinalphos 25 EC @ 2 ml/lit and azadiractin 1500 ppm @ 2 ml/lit in reducing the larval population of
H armigera, Similarly,
Narasimhamurthy and Ram Keval (2012) reported HaNPV @ 500 LE/ha as the highest reduction of larval population of
H. armigera larvae.
Byrappa et al., (2012) have also found sequential application of NSKE-HaNPV-Bt effective against
H. armigera larvae.
Parmar et al., (2015) reported that Spinosad 2.5 SC (0.002%) was the most effective against gram pod borer in black gram along with Taggar and Singh (2015) also reported that Spinosad 45% SC (73 g a.i/ha) effective against the pod borer,
H. armigera in pigeonpea, followed by commercial Bt formulation (1.5 kg/ha).
Kumar et al., (2012) have observed Spinosad 45 SC @ 90 g a.i./ ha as most effective treatment followed by Indoxacarb 14.5 EC @ 50 g a.i/ ha for the management of
H. armigera and
Choudhary et al., (2013) found that Spinosad @ 56 g.a.i/ha, was gave the second best result in controlling okra fruit borer,
Helicoverpa armigera (Hübner).
In agreement with the present findings,
Singh et al., (2014a) recorded that Indoxacarb 14.5 SC @ 60 g.a.i.ha
-1 effective treatment for
Helicoverpa management and HaNPV @ 400 LE was least effective treatment compared to other new insecticide molecules.
Babariya et al., (2010) also found Indoxacarb 0.0075% giving the highest per cent mortality of the pest as in present study and
Awale et al., (2014) reported Indoxacarb @ 21.75 g a.i
./ha as second best treatment in reducing
H. armigera larval population in pigeonpea.