screening elite genotypes and ipm of defoliators in groundnut

The early instar larvae scraped the chlorophyll content of the leaves from
undersurface. Later instars caused severe defoliation. Their population varied from 1.64 to
4.42 with an average of 2.43 ± 0.86 larvae / plant.
Tobacco caterpillar, Spodoptera litura was observed during vegetative stage of the
crop from 37 DAS to 79 DAS. Early instars larvae were gregarious and scraped the
chlorophyll content from under surface of leaves, resulted in skeletonisation. Later instars
spread and fed on leaves voraciously. The population ranged between 1.86 to 13.84 larvae/
plant. Initially the population was less (1.86 larvae/ plant) whereas gradually the population
was increased (13.84 larvae/ plant) with the mean value of 7.38 ± 3.99.
Bihar hairy caterpillar, Spilosoma obliqua scraped the green mater from under
surface of leaves and skeletonised them in the early instars. The grown up caterpillar
defoliated the crop. This pest was noticed on the crop from 37 DAS to 79 DAS with mean
larval population of 6.17 ± 3.47. Initially the larval population was less (1.48 larvae/ plant) and
it was increased to 11.56 larvae/ plant at end of the crop stage (Table 14).
4.2.7 Incidence of defoliators on main and trap crop
The defoliator pest population was more on sunflower compared to groundnut at all
the stages of the crop. The semiloopers population varied from 1.24 to 1.72 larvae / m row in
groundnut whereas in sunflower varied from 1.64 to 4.42/ plant.
The population of S. litura and S. obliqua varied from 1.48 to 3.96 and 0.78 to 1.11
larve/ m row respectively in groundnut whereas in sunflower, the population ranged from 1.86
to 13.84 and 1.48 to 11.56 larvae/ plant (Table 15).
4.2.8 Natural enemy population in different IPM modules of groundnut
Natural enemy population was recorded in all the three IPM modules of groundnut.
4.2.8.1 Coccinellids
Coccinellid population was noticed on the crop 21 DAS to 63 DAS. Both adult and
grubs were predators on sucking pests. The population both adult and grubs were ranged
from 1.20 to 2.40 and 1.20 to 2.60 per m row respectively in M-I. Whereas in M-II the adult
and grub population was ranged from 2.00 to 3.80 and 2.40 to 3.80 grubs per m row
respectively. In M-III, the population of adult and grubs were ranged between 1.00 to 2.00 and
1.00 to 1.80 respectively (Table 16).
Paired ‘t’ value, module-II and module-I differed significantly and module-II and
module-III also varied significantly from each other. Module-II was significantly superior over
module-I and module III during 21 DAS to 63 DAS.
4.2.8.2 Syrphids
Syrphid population was observed on the crop from 21 DAS to 63 DAS. The
population ranged between 1.40 to 2.70 syrphids / m row in first module. In second module
Syrphid population was varied from 2.60 to 3.90. Whereas in third module it was differed from
1.00 to 1.80 (Table 17).
As per Paired ‘t’ value, all the three modules varied significantly from each other.
Module-II was significantly superior over module-I and module-III during 21 DAS to 63 DAS.
Where the module-I was significantly superior over module-III.
4.2.8.3 Campoletis chlorideae
It was observed in large proportion during August and September. The incidence was
noticed on the third instar larvae of S. litura during 37 to 79 DAS. The population ranged