Effect of natural products on growth and development of Agrotis segetum (Denis and Schiffermuller)
Loading...
Date
2021-11-10
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Palampur
Abstract
The present investigation entitled “Effect of natural products on growth and development of Agrotis segetum
(Denis and Schiffermuller)” was undertaken during 2020-2021 in the Department of Entomology, CSK
HPKV, Palampur. The effect of natural products viz., Neemastra, Agniastra and Brahmastra at
concentrations ranging from 2.5 to 40 per cent and azadirachtin at concentrations ranging from 1.25 to 20
ppm was studied on developmental biology of A. segetum under laboratory conditions on cabbage. The
natural products impaired the normal development of A. segetum by prolonging the developmental period in
dose dependent manner. However, the adult longevity, oviposition period, post-ovipostition period and
fecundity were reduced with increasing concentrations of natural products. The maximum prolongation of
incubation period (3.02 days), larval period (25.23 days), pre-pupal period (2.11 days), pupal period (10.02
days), pre-oviposition period (3.00 days) as compared to control 2.17, 20.97, 1.34, 9.04, 2.23 days,
respectively was observed at 40 per cent concentration of Brahmastra. Brahmastra (40%) proved to be most
effective, in reducing male longevity (9.54 days), female longevity (7.90 days), shortening oviposition
period (2.49 days), post-ovipostition period (2.05 days) and reducing the fecundity (775.00 eggs) as
compared to control 10.72, 8.92, 4.13, 2.68 days and 887.67 eggs, respectively. The survival percentage of
each stage was reduced with increasing concentrations of natural products and maximum reduction was
observed in Brahmastra (40%). The percent hatchability of eggs (93.33%), larval survival (51.11%), prepupal survival (52.22%), pupal survival (45.56%) and adult survival (45.56%) were reduced as compared to
control 100.00, 84.44, 81.11, 78.89 and 78.89 per cent, respectively. Azadirachtin (1.25-20 ppm) had
prolonged the incubation period, larval period, pre-pupal period, pupal period and pre-oviposition period
ranging between 3.57-4.32, 26.10-29.17, 2.33-2.97, 10.94-11.58 and 2.70-3.44 days, respectively. The male
longevity, female longevity, oviposition period, post-oviposition period and fecundity were reduced from
7.73 to 6.92, 6.17 to 5.31, 3.17 to 2.36, 1.92 to 1.36 days, respectively and 751.0 to 667.0 eggs at
concentrations ranging from 1.25 to 20 ppm, respectively. The feeding inhibition (FI) studies of different
natural products viz., Neemastra, Agniastra, Brahmastra and garlic+chilli extract in concentrations ranging
from 2 to 32 per cent and azadirachtin concentrations ranging from 2 to 32 ppm were evaluated against 3rd
and 6th instar larvae of A. segetum. Based on FI50 values, the order of feeding inhibition of the natural
products tested against the third and sixth instar larvae was observed as: Brahmastra (5.81 and
6.61%)>Neemastra (6.12 and 7.04%)>garlic+chilli extract (6.39 and 7.49%)>Agniastra (6.44 and 8.62%),
respectively. While the FI50 values of azadirachtin against these instars was calculated to be 4.90 and 5.15
ppm, respectively.