Ethnobotanical Leaflets 12: 938-43. 2008. Antifeedant
Activity of Leaf Aqueous Extracts of Selected Medicinal Plants on VI instar
larva of Helicoverpa armigera (Hübner) 1 School of Biotechnology,
Chemical and Biomedical 2 P G and Research
Department of Botany, 3 Department of Zoology, RD
4 Department of Botany, RD Issued ABSTRACT Phytochemicals,
especially botanical insecticides are currently of interest because of their successful
application in plant protection as biocontrol agents. Biological activity of
leaf aqueous extract of ten selected medicinal plants were evaluated against the
fourth-instar larvae of gram pod borer Helicoverpa
armigera (Hübner), (Lepidoptera: Noctuidae).
Antifeedant activity of leaf aqueous extracts of Abutilon indicum L.,
Achyranthus aspera L., Aerva lanata
L., Albiziz amara (Roxb), Andrographis paniculata Ness., Cardiospermum halicacabum L., Cassia tora L., Catharanthus roseus L (G) Don., Datura metal L. and Tribulus
terrestris L. were evaluated in this study. Preliminary screening after
24 h of exposure with leaf aqueous extracts of the selected plants at a
concentration of 1,000 ppm exhibited significant larval mortality rate. The
percentage mortality rate ranged considerably from 10.8 to 72.8. The mortality
rate was observed in the decreasing order of A. paniculata > C.
roseus > D. metal > A. amara > C. halicacabum > A.
indicum > C. tora > T.
terrestris > A. aspera >A.
lanata against the larvae of H.
armigera. The results imply that leaf aqueous extract of A. paniculata, C. roseus and D. metal can potentially be used as
eco-friendly pest control agents against the larva of H. armigera. INTRODUCTION During the last 50 years, worldwide use of synthetic insecticides to control insect pests has led to both insecticide resistance and environmental persistence (Roush, 1990). Plant derived phytochemicals have been widely used in the management of agricultural pest since time immemorial (Choudary, 2001). Plant derived pesticides are eco-friendly, non-toxic to non target organisms, non persistent in nature, besides they do not promote drug resistance (Liu et al., 2000). Therefore, researchers world over are engaged in a mission to hunt for novel phytochemicals that could potentially be used in the management of insect-pests. Plants are
endowed with a potential to produce a range of secondary metabolites like
alkaloids, terpenoids, flavonoids, phenols, glycosides, sitosterols and
tannins. These phytochemicals are known to protect the plants from the attack
of insect-pests (Ahmad, 2007). However, production of phytochemicals varies
from plant to plant. Further, parameters like age of plant, part of plant
(root, stem, leaf, fruit, flower, seed and bark) have been reported to affect
the production of phytochemicals. The phytochemicals produced in response to
insect-pest attack, affect feeding and oviposition of insects on the plants. Application
of bio-pesticides has been reported to have positive impacts on bollworm
population management (Ge and Ding 1996). A number of plants have been shown to have pesticidal and
antifeedant activity against H. armigera of which
Neem has been subjected to extensive investigation by Chopra et al., (1994). Studies have shown
that Acorus calamus, Annona squamosa,
Vitex negundo are effective in the management of H. armigera (Murugan et al.,
1998). Sundararajan and Kumuthakalavalli, (2001) evaluated antifeedant
activity of aqueous extract of Gnidia glauca and Toddalia asiatica
against H.
armigera. In this view, effect of leaf aqueous extracts of selected
medicinal plants viz., A. indicum, A.
aspera, A. lanata, A. amara, A. paniculata, C. halicacabum, C. tora, C. roseus, D. metal and T. terrestris
have been evaluated for their efficacy in the management of the insect pest H. armigera. MATERIALS Preparation of extract Selection
of plants used in the present study was made on the basis of their
availability and absence of damage by the insect-pest. Healthy plant
materials were collected from the wild in poly bags and brought to lab and
their botanical identity was established. Fresh leaves from the selected
plants were collected and washed separately. About 1gm of fresh leaf material
was ground with distilled water using mortar and pestle. The extract was
filtered and the filtrate was made upto 100ml and was maintained as stock.
The leaf aqueous extract was diluted with distilled water to obtain 1% test
solution used in the bioassay studies. Test organism The larvae used for the study were collected from the
host plants in the cotton fields and brought to lab. They were reared on
artificial diet under laboratory conditions. Studies were carried out using VI instar larvae of H. armigera against the aqueous extract of all
the selected plant species. The percentage mortality was calculated after a
period of 24h by using bioassay studies. Bioassay studies Studies were conducted for a period of 24h in the
laboratory in transparent plastic containers of 4x2.5 cm size capped with
perforated plastic lids. Fresh leaves of Lycopersicum
esculentum (tomato) were collected from the field and washed in water.
Excess moisture was removed from the leaves and the leaves were dipped in 1% test
solution, shade dried and served to the VI instar larvae of H. armigera. Extract free leaves
served as control. For each treatment 10 larvae were singly introduced in
separate containers after six hour starvation. Three replicates each of ten
larvae were maintained for each treatment. All the experiments were conducted
at 27± 1℃, 75% humidity and 14h dark period. Twenty four hour
larval mortality was observed and the percentage mortalities were corrected
using Abbott’s formula (Abbott, 1925). RESULTS The
aqueous extracts of selected plant species collected from DISCUSSION Prohibitive
expense to meet the challenges of increasing resistance in insects,
resurgence of pests and escalating environmental pollution caused by
synthetic pesticides call for the discovery of less-expensive, non-hazardous
alternatives in the management of insect-pests. Plants are endowed
with a potential to produce a wide spectrum of allelo-chemicals (Norduland
and Sauls, 1981). Insects have been influential in the evolution of
allelo-chemicals in plants which in turn affects the insects. Some of
compounds affect the feeding behavior of the insects and inhibit feeding,
while few others disrupt hormonal balance there by inhibits growth,
metamorphosis and reproduction. Due to aforesaid reasons there is resurgence
of interest in plant derived compounds for developing them novel eco-friendly
insecticides on commercial scale (Jacobson and Crosby, 1971). Despite
hundreds of plants have insecticidal property, only few compounds like
Azadirachtin (known to disrupt the action of moulting hormone) and
pyrethroids (brings about paralysis of the insects) have been commercialized.
However, an understanding of structure-activity relationship and knowledge on
the mode of action is required for large-scale production. For successful exploitation of a bio-insecticide,
screening of phytochemicals for wide spectrum of behavioral and physiological
activities in poly-phagous insects is essential. Koul et al., (2000) administered phytochemical extracts orally through food to determine the toxicity or efficacy of plant materials for antifeedancy, inhibition of growth or emergence as adults. Murugan et al (1998), followed no-choice method in which the test insect was provided with treated leaf disc. Dual choice method mimics the situation in the field, and is valuable in assessing the antifeedancy of phytochemicals. However, this method does not facilitate administration of apt quantity of plant extract to the insects. On the other hand, no-choice bioassay method provides on opportunity to precisely administer the desired quantity of extract to the insect. Hence in the present study, no-choice bioassay method was followed for assessing the insecticidal activity of the different plant extracts. Usually larger doses of plant extracts inflict mortality either by inhibiting feeding or reducing digestibility or inhibiting growth. Smaller doses of extracts may not be adequate for killing the insects however it may sometimes induce malformation (Ahmad, 2007). Induction of morphogenetic deformities during larval development or metamorphosis has greater impact on population build up. Malformed adults are unable to participate in reproductive activities and hence do not help building up the population. High antifeedancy (low ED50) has been reported for pure compounds isolated from different plants by Simmonds et al., (1990). Aqueous extracts of Calotropis procera and Datura stromonium display about 90% feeding protection against H. armigera (Dodia et al., 1998). Likewise,
it has been reported that the effectiveness of the phytochemicals depend on
the extraction method used. Janarthan et
al., (1999) reported that petroleum ether extracts of Parthenium histerophorus at a
concentration of 0.2 and 0.5% cause 100% mortality in the larvae of H. armigera. Antifeedant property of
plant extracts brings about retardation of growth and ultimately results in
death of the insect. However, compounds which do not display antifeedant
property are reported to have growth regulatory activity (Kraus et al., 1987). On the other hand, a
few plant extracts display bimodal activity. At high concentrations they are
as feeding deterrents and at low concentrations as growth inhibitors (Nawrot et al., 1991). Jermy (1990) reported that extracts with antifeedant and toxic effect
are more successful in practical application as they evoke behavioral effect
of antifeedancy. Jaglan et al
(1997) evaluated the effect of Azadirachta
indica extracts against H. armigera
and reported that Chloroform : methanol (9:1) extracts of Neem seed kernels
and leaves showed better insecticidal properties than methanol extracts. On the other hand Koul et al., (2000) reported that H.
armigera larva fed on azadirachtin treated leaf suffered dose dependant
effect on growth. Young larvae fed on 4 ppm azadirachtin treated leaf
initially gained weight however, older larvae fed on 4 ppm azadirachtin leaf
suffered 75% decrease in growth compared with the control larva (Koul, 1985).
Similar observations were made by Murugan and Babu (1998) on growth and
feeding physiology of H. armigera larva
on extracts of Ricinus communis, Glycosmis pentaphylla, Vitex negundo and Nerium oleander. Murugan et al., (1998) reported that larvae
fed on 0.3% ethylaceteate fraction of Glycosmis
pentaphylla, Vitex negundo and
Nerium oleander showed significant effect on initial weight (259, 181 and
177%) in 48h compared to weight gained by the control larva (898, 972 and
890%). However, earlier it has been reported that the aqueous leaf
extracts of Gnidia glauca showed more than 50% larval mortality at
0.8-1.0% and 86.1% mortality observed at 1.0% on Toddalia asiatica
extract against the sixth-instar larvae of H. armigera
(Sundararajan and Kumuthakalavalli, 2001). In the
present study all the tested plant extracts exhibited antifeedant activity on
H. armigera. Of the 10 species of
the plants screened for insecticidal property, three plant species (A. paniculata, C. roseus and D. metal) showed high rate of mortality,
i.e. above 60%, on application of aqueous extracts against the VI instar
larva of H. armigera. In
conclusion, the study reveals that leaf aqueous extracts of A. paniculata, C. roseus and D. metal can potentially be used as
eco friendly bio-pesticide to control the devastating damage caused by VI
instar larva of H. armigera. REFERENCES Abbott WS (1925) A method for computing the effectiveness of an insecticide J Econ Ent 18:265-267. Ahmad Mahmood (2007) Insecticide resistance mechanisms and their Management in Helicoverpa armigera (Hübner) - A review J Agric Res 45(4): 319-335. Chopra RN, Badhwar R and
Ghosh S (1994) Poisonous Plants of Choudhary RK, Veda OP and Mandloi KC (2001) Use of Neem, Azadirechta indica and garlic, Allium sativum in the management of bolloworms, Helicoverpa armigera in cotton In: Proc 88th Session of the Indian Sci Cong Agric Sci, New Delhi. 40-42. Dodia DA, Patel IS and Jacobson (1982) The
potential role of natural product chemistry research in Heliothis management. In: Proc. Internt. Patacheru, Jacobson M and Crosby DG (1971). Naturally occurring insecticide (Eds Marcel and Dekker) 212-219. Jaglan MS, Janardhan RS, Chitra KC,
Kameswara RP and Subramaniyam RK (1999) Antifeedant and insecticidal
properties of certain plant extracts against Helicoverpa armigera J Insect Sci, 5:163-164. Jermy T (1990) Prospects of antifeedant approach to pest control – a critical review J Chem Ecol, 16:3151-3166. Koul O (1985) Azadirachtin interaction with development of Helicoverpa armigera Fab Indian J Expt Biol 23:160-163. Koul O, Jain MP and Sharma VK (2000) Growth inhibitory and antifeedant activity of extracts from Melia dubia to Spodoptera litura and Helicoverpa armigera larvae. Indian J Exp Biol 38(1):63-68. Kraus W, Baumann S, Bokel
M, Keller U, Klenk A, Klingele M, Pohnl H and Schwinger M (1987) Control of
insect feeding and development by constituents of Melia azadirach and
Azadirachta indica Proc 3rd International Neem Conference, Manjunath TM, Bhattnagar
VS, Pawer CS and Sidhanantham S (1985) Economic importance of Heliothis armigera (Hubner) in Michael AF and Donald CS
(1996) Inundative biological control of Helicoverpa zea (Lepidoptera:
Noctuidae) with the entomopathogenic nematode Steinernema riobravis
(Rhabditida: Steinernematidae) Biol
Control Murugan K and Babu R (1998) Impact of certain plant products and Bacillus thurengiensis Berliner sub sp. kurstaki on the growth and feeding physiology of Helicoverpa armigera (Hubner) JSIR 57:757-765. Murugan K, Sivaramakrishnan S, Senthilkumar N, Jayabalan D and Senthil Nathan S (1998) Syneristic interaction of botanicals and Biocides Nuclear polyhedrosis virus on pest control JSIR 57:732-739. Nawrot J, Koul O, Norduland DA and Sauls GE (1981) Kairomones and their use for the management of entomophagous insects J Gen Ecol 7:1057-1061. Roush R T and BE Tabashnik (1990) Pesticide resistance in
arthropods. Chapman and Hall, Simmonds MSJ, Blaney WM and Fellows FE (1990) Behavioral and electro-physiological study of antifeedant mechanisms associated with polyhydroxy alkaloids. J Chem Ecol 16:3167-3196. Sundararajan G and Kumuthakalavalli R (2001) Antifeedant activity of aqueous extract of Gnidia glauca Gilg. and Toddalia asiatica Lam. on the gram pod borer, Helicoverpa armigera (Hbn). J Environ Biol 22(1):11-14. Table
1 Effect of leaf aqueous solutions on the larvae of H. armigera.
|