DEVELOPMENT AND EVALUATION OF BOTANICAL FORMULATIONS AGAINST MAJOR DEFOLIATORS OF GROUNDNUT 3771
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Date
2023-09
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JAU JUNAGADH
Abstract
The present investigation was carried out with the aim of “Development and
evaluation of botanical formulations against major defoliators of groundnut” and
planned to extract the active compounds with different solvents, identification of
active compounds, development of botanical formulations, evaluation of developed
botanical formulation under laboratory and field conditions against S. litura and H.
armigera on groundnut. The laboratory experiments were studied under the
Biocontrol Research Laboratory, Department of Entomology, while field experiments
were carried out in the Instructional Farm, Department of Agronomy, Junagadh
Agricultural University, Junagadh during the summer seasons of the year 2021-22
and 2022-23.
A total of eleven botanical plant samples of selected plant parts were collected
from Lalbagh and the nursery of JAU, Junagadh, Gujarat. The selected plant materials
were extracted with different organic solvents (acetone, methanol, hexane, ethanol
and dichloro methane) using the Soxhlet apparatus. Among all the solvents, methanol
solvent recorded the maximum product yield compared with other solvents. In
methanol solvent, neem recorded the maximum yield recovery with 20.40% followed
by custard apple (18.41%), pongamia (16.55%), eucalyptus (12.91%) and vitex
(12.51%).
The identification of active compounds from methanol crude extract of
different botanical plants was analysed by using GC-MS analysis. The compounds
such as octadecanoic acid, betulin, oleic acid, squalene, α-amyrin, 1,8-cineole,
caryophyllene, p-cymene, thymol, phytol, linalool, methyl eugenol, eucalyptol,
estragole, limonene, ursolic acid, p-hydroxy benzoic acid, scopolamine, n hexadecanoic acid, atropine, hyoscyamine, syringaldehyde, syringic acid and γ sitosterol were identified in various botanical crude extracts (neem, pongamia, custard
apple, eucalyptus, tulsi, vitex, datura, jatropa, calotropis, henna and nerium). These
compounds were responsible for insecticidal activity against different insect pests.
The methanol crude extract of different botanicals were evaluated to study
their efficacy against S. litura and H. armigera under laboratory conditions. The
results revealed that methanol crude extract of neem, custard apple, pongamia,
eucalyptus and vitex recorded more than 80% and 75% mortality against S. litura and
H. armigera, respectively. These five treatments were significantly superior to other
treatments. These top five botanical crude extracts were used further in the
development of the botanical formulations.
The developed 40 EC, WP and WDG formulations of neem, pongamia,
custard apple, eucalyptus and vitex passed all the physicochemical studies viz.,
emulsion stability, cold test, pH test, wettability test, suspensibility test, dispersibility
test, disintegration time and accelerated storage temperature. These developed
botanical formulations were further used to study their efficacy against major
defoliators under laboratory and field conditions.
The developed formulations of five different botanicals each with five
different concentrations studied against S. litura and H. armigera under laboratory
conditions by leaf disc bioassay method. The results of EC formulations showed that
neem, custard apple, pongamia and vitex 40 EC 1.5% recorded mortality of more than
75% and 65% on S. litura and H. armigera, respectively. The LC50 values ranged
from 0.63 to 0.97% and 0.90 to 1.12% on S. litura and H. armigera, respectively.
The results of WP formulations revealed that neem, custard apple, pongamia
and vitex 40 WP 1.50% recorded more than 80% and 70% mortality on S. litura and
H. armigera, respectively. The LC50 values of these botanical WP formulations
ranged from 0.53 to 0.89% and 0.73 to 0.99% on S. litura and H. armigera,
respectively. Whereas, the WDG formulation of neem, custard apple and pongamia
40 WDG 1.50% recorded more than 70% and 50% mortality and median lethal
concentration (LC50) of WDG formulations ranged from 0.73 to 0.99% and 1.30 to
1.75% against S. litura and H. armigera, respectively.
The bio-efficacy of developed botanical formulations was evaluated at the
field level. The results revealed that neem 40 WP 1.50% recorded the lowest larval
population which was found statistically at par with custard apple 40 WP 1.50%. The
treatments, neem 40 EC 1.50%, custard apple 40 EC 1.50%, azadirachtin 0.15%
neem 40 WDG 1.50% and custard apple 40 WDG 1.50% were found next better
treatmens for effective management of defoliators (S. litura and H. armigera) in
groundnut.
The data on groundnut yield revealed that maximum (1983 kg ha-1 ) yield was
recorded in neem 40 WP 1.5% treated plots followed by custard apple 40 WP 1.5%,
neem 40 EC 1.5%, custard apple 40 EC 1.5% and azadirachtin 0.15% with 1883,
1849, 1817 and 1750 kg ha-1
, respectively. The maximum ICBR was recorded in
neem 40 WP 1.5% (1:15.20) followed by custard apple 40 WP 1.5% (1:13.65), neem
40 EC 1.5% (1:13.13), custard apple 40 EC 1.5% (1:12.64) and azadirachtin 0.15%
(1:12.69).
From the overall results of the present investigation, it can be concluded that
methanol extract of developed botanicals formulations (WP, EC and WDG) of neem
and custard apple was found to be promising against S. litura and H. armigera in
groundnut. Therefore, it can be used in Integrated Pest Management (IPM)
programmes to reduce the usage of synthetic chemical insecticides.