Index

Abstract

Antifeedant, larvicidal and ovicidal activities of fractions isolated from ethyl acetate crude extracts of Barleriabuxifolia leaves were tested against fourth instar larvae of Spodopteralitura and Helicoverpaarmigera. The maximum antifeedant, ovicidal and larvicidal activity was recorded in fraction III of B. buxifolia against S. litura and H. armigera. Whereas significant larval mortality was observed in fraction III of B. buxifoliaon S. litura (78.66%) and H. armigera(73.76%) at the same concentration. These results indicate that B. buxifolia has the potential to serve as an alternate botanical pesticide in the management of Spodopteralitura and Helicoverpaarmigera.

Keywords: Antifeedant, Insecticidal, Ovicidal activities, Spodopteralitura, Helicoverpaarmigera, Barleriabuxifolia.

Received: 14 April 2017 / Revised: 18 May 2017 / Accepted: 23 June 2017 / Published: 20 July 2017

Contribution/ Originality

This study to approach the novel aspects of plant phytochemicals act as insecticides against economically important pest. Fractions isolated from B. buxifoliaand tested for insecticidal activity on S. litura and H. armigera is new report in this plant. Further, it may identify the active principles which may use as potential plant derived insecticide.


1. INTRODUCTION

The environmental problems caused by overuse of pesticides have been the matter of concern for both scientists and the public in recent years. It has been estimated about 2.5 million tons of pesticides are used in crop protection for each year and the worldwide damage caused by pesticides reaches 100 billion annually [1 ]. Due to a higher dose and repeated frequency of application, every year one million people suffer from pesticide poisoning, cardiopulmonary, neurological and skin disorders, fetal deformities, miscarriages, lowering the sperm count of applicators. Insect pests play a major role in damaging the agricultural crops and the loss varies between 10% and 30% for major crops [2 ]. In india, Spodopteralitura Fabricius (Lepidoptera: Noctuidae) is one of economically important insect and it damages many economically important crops including cotton, pigeonpea, chickpea, tomato, okra, and black gram [3 ]. The cotton bollworm, Helicoverpaarmigera (H. armigera) (Hübner) (Lepidoptera: Noctuidae) is a polyphagous pest worldwide that inflicts crop damage in India to the sum of one billion dollars annually and it attacks over 200 crop species belonging to 45 families [4 ].These pests status is well justified in its polyphagy on all economically important crops and the hurdles in its management. These insect pests have been controlled with the help of synthetic insecticides over the past fifty years [5 ].

Botanical pesticides provide an alternative to synthetic pesticides because of their generally low environmental pollution, low toxicity to humans and other advantages. While plant chemicals may produce toxic effects when ingested by insects, antifeeding activity may determine the extent of insect herbivory. Several papers have been published on the entomotoxic properties of crude extracts from different plant species [6 , 7 ]. Plants are endowed with a potential to produce a range of secondary metabolites like alkaloids, terpenoids, flavonoids, these phytochemicals are known to protect the plants from the attack of insect-pests. Phenols, glycosides, sitosterols and tannins.Solanummelongena., Lycopersiconesculentum And Capsicum annuum. (Solanaceae) are widely cultivated in India and other parts of the world. Few reports are available using C. annuumfruit powder [8 ]. However, primary work on Barleriabuxifoliabiological properties against agricultural insect pests has been already reported [9 ]. Further, the present investigation was carried out to evaluate the antifeedant, insecticidal and growth inhibitory activities of isolated fractions of Barleriabuxifolia against economically important pests.

2. MATERIALS AND METHODS

2.1. Collection of Plant Materials

The leaves of Barleriabuxifolia were collected from Pulliansolai, Kolli hills, namakkal District, Tamil Nadu, India during the July 2015. Collecetd plant specimen was identified by Dr. S. John Britto, Director, The Rapinat Herbarium and Centre for Molecular Sytematics, St’ Joseph’s College, Tiruchirapalli, Tamil Nadu, India and The Voucher specimen (IPH 16) was deposited in Entomology lab, Arignar Anna Government Arts College, Musiri, Tamil Nadu, India. The plant leaves were carefully washed with clean water and shade dried under room temperature (27.0 ± 2°C) at Entomology lab, PG & Research Department of Zoology, Arignar Anna Government Arts College, Musiri, Tamil Nadu, India.

2.2. Extraction and Fractionation

The plant materials were thoroughly washed with tap water and shade dried under room temperature (27.0± 20C and 75 ± 5% RH). After complete drying the plant materials were powdered using electric blender and sieved through a kitchen strainer. 1000g of plant powder was extracted by soxhlet extraction methods with ethyl acetate solvent and filtered through Whatman’s No. 1 filter paper. The solvent from the crude extract were evaporated to air dried at room temperature.

Crude ethyl acetate extract (15g) was separated by silica gel (100-200 mesh) column (size 60cm x 4 cm) chromatography and eluted with hexane 100% followed by the combination of hexane : chloroform (9:1, 8:2, 7:3, 6:4, 5:5, 4:6, 3:7, 2:8 and 1:9), then chloroform and Similarly the column was run over chloroform, then chloroform: ethyl acetate (9:1, 8:2 and 1:9) and then ethyl acetate respectively. A total of 118 fractions were collected in 10ml test tubes and pooled into 7 fractions based on similar RF values using thin layer chromatography.

2.3. Rearing of Test Insects

Egg mass of S. litura and different larval stages of H. armigera were collected from vegetable field at Anaipatti, Musiri, Trichirappalli, Tamil Nadu, and India. Larvae were reared in laboratory conditions (27.0˚C ± 2˚C; 70% RH) throughout the study period at PG & Research Department of Zoology, Government Arts College, Musiri, Tamil Nadu, India. Generally, healthy and uniform sized fourth instar larvae were used for the experiments and the cultures were maintained throughout the study period.

2.4. Antifeedant Activity

Antifeedant activity of the fractions of B.buxifolia was studied using leaf disc no choice method [10 ]. Required concentration of the fractions of B. buxifolia (1000ppm) was prepared by dissolving in acetone and mixing with dechlorinated water Polysorbate 20 (Tween 20) at 0.05% was used as an emulsifier [11 ]. Fresh cotton leaf (for H. armigera) and castor leaf (for S. litura) discs of 3 cm diameter were punched using a cork borer and dipped in 125,250, 500, and 1000ppm for fractions separately and air dried for 5 minutes. After air drying, treated leaf discs were kept inside the Petri dishes (15mm × 90 mm diameter) separately containing wet filter paper to avoid drying of the leaf disc and single 2hrs pre starved fourth instar larva of H. armigera and S. litura was introduced on each treated leaf disc.Neemazal was considered as constant. Ten replications were maintained for each treatment. A progressive consumption of leaf area by the larva in 24 hrs period was recorded in control and treatments using a leaf area meter (systronics 211). Leaf area consumed in plant extract and fraction treatments was corrected from the control. The percentage of antifeedant index was calculated using the formula of Ben Jannet, et al. [12 ].

C - T
AFI= -------------×100
C + T
Where
AFI = Antifeedant Index;
C = Area protected in control leaf disc;
T = Area protected in treated leaf disc.

2.5. Larvicidal Activity

For the evaluation of larvicidal activity of the fraction of B.buxifolia against the selected pest, primarily, the plant extract was tested on a wide range of concentration, from that a narrow range of concentration was derived. Thus, 125,250, 500, and 1000ppm concentrations for fractions were tested against the freshly moulted (0-6h) fourth instar larvae of H. armigera and S. litura .The branches bearing cotton leaves were tied with wet cotton plug to avoid early drying and placed in a plastic trough (29cm × 8cm). In each concentration 10 pre-starved (2hrs) fourth instar larvae were introduced individually and covered with muslin cloth. Neemazal was considered as constant. Five replicates were maintained for each concentration, each replicates comprised of 25 numbers of larvae. After 24h of the exposure period, the number of dead larvae was recorded from each replicates at all the concentrations and the percentage of larval mortality was calculated using Abbott’s formula [13 ]. The larvae with no symptom of a movement or shake while touching with soft camel brush were considered as dead.

%MT - %MC
Mortality (%) = --------------------------×100
100 - %MC
Where,
% MT = % Larvae mortality in treatment and
% MC = % Larvae mortality in control.

2.6. Ovicidal Activity

Twenty individual eggs of H. armigera andS.litura (for removal of scales from egg masses by using camel brush) were separated and dipped in various concentrations (as mentioned in antifeedant activity). Five replicates were maintained (n=100). Number of eggs hatched in the control and treatments were recorded and percent ovicidal activity was calculated according to Abbott [13 ] (as mentioned in larvicidal activity).

2.7. Statistical Analysis

Data analysis was carried out using Microsoft Excel 2007. One -Way ANOVA was performed for all the expe-rimental data from that Least Significant Difference was calculated and the significant differences were marked with different alphabet.LC50, LC90 was carried out using SPSS 16.00.

3. RESULTS AND DISCUSSION

The results of the antifeedant potential of the solvent crude extracts of B. buxifolia investigated against S.litura and H. armigera larvae were presented in Table 1. Maximum antifeedat activity was recorded in fraction III followed by fractionVI against 74.33% and 57.32% for S. litura and 70.11% and 50.43% for H. armigera at 1000ppm concentration. Percentage ovicidal activity for fractions of B.buxifolia, studied at different concentration against S. litura and H. armigera was presented in table2. Maximum ovicidal activity was recorded in fraction III followed by fractionVI against 76.84% and 62.06% for S. litura and 73.12% and 67.02% for H. armigera at 1000ppm concentration. Percentage larvicidal activity for fractions of B.buxifolia, studied at different concentrations against S. litura and H. armigera was presented in table 3. Significantly promising larval mortality was recorded at 1000ppm concentrations of different fractions showed increased larvicidal activity in fraction fractionVI fraction III against (68.26% and78.66% for S. lituraand (58.84% and 73.76%) for H. armigera respectively.

The botanical extracts from the plant leaves, roots seeds, flowers and bark in their crude form have been used as conventional insecticides in throughout the world. Several authors have reported that plant extracts possess similar type of antifeedant, insecticidal, oviposition deterrent, ovicidal and growth inhibition activities against lepidopteran pests [14 ]. Antifeedant, larvicidal and insect growth inhibitory activities of Pseudocalymma alliaceum were studied against S. litura and H. armigera[15 ]. Antifeedant, larvicidal and insect growth inhibitory activities of Barleria longiflora were studied against S. litura and H. armigera[16 ]. Antifeedant, larvicidal and insect growth inhibitory activities of Pseudocalymma alliaceum were studied against S. lituraand H. armigera. Chinnamani, et al. [15 ]in the present study, it was observed that III fraction of B. buxifoliareduced the feeding rate of S. litura and H. armigera. Jeyasankar, et al. [17 ] reported that the possible insecticidal property in the selected plant may arrest the various metabolic activities of the larvae during the development and ultimately the larvae failed to moult and finally died. This is in accordance with the earlier findings of In the present investigation, III fraction of B. buxifolia at 1000ppm concentration was recorded then maximum larval mortality of 78.66% S. lituraand73.76% H. armigera. Secondary plant compounds act as insecticides by poisoning per se or by production of toxic molecules after ingestion. These compounds also deter or possibly repel an insect from feeding Lajide, et al. [18 ]. Baskar, et al. [19 ]Observed that twelve fractions were collected from hexane extracts of Couroupita guianensis were studied against H.armigera. Among them, eight fractions showed maximum percentage of larvicidal (80.88%) activity against H. armigera at 1,000ppm concentration respectively. In the present study III fraction isolated from ethyl acetate extract of B. Buxifolia exhibited statistically significant larvicidal activity against fourth instar larvae of S. lituraand H. armigera at 1000ppm concentrations. Present results agreed with Atalantia monophylla leaf extract was fractionated using silica gel column chromatography. Twelve fractions were collected and evaluated for their ovicidal activity at 125, 250, 500 and 1000 ppm concentrations. Among them, fraction 9 showed maximum ovicidal activity of 72.21% at 1000 ppm concentration with least LC 50 value of 435.92 ppm [20 ].

Funding: The Authors are thankful that this work was conducted in the laboratory which is financially supported by UGC, New Delhi, India (Ref No. 42-570/2013 (SR)).
Competing Interests: The authors declare that they have no competing interests.
Contributors/Acknowledgement: The authors are thankful to Principal and Head of Department of Zoology, A. A. Govt. Arts College, Musiri-621 211, Tamil Nadu, India for their support and facilities provided.

 

REFERENCES

[1]          USEPA (United States Environmental Protection Agency), "Pesticide news story: EPA releases Report containing latest estimates of pesticide use in the United States," 2011.

[2]          P. C. Abhilash and N. Singh, "Pesticide use and application: An Indian scenario," Journal of Hazardous Materials, vol. 165, pp. 1-12, 2009. View at Google Scholar | View at Publisher

[3]          K. Sahayaraj and P. Sathyamoorthi, "The toxicity and biological effect of pedalium murex L.extracts on the tobacco cutworm, spodoptera litura (Fabr.) larvae," Archives of Phytopathology and Plant Protection, vol. 43, pp. 1768-1780, 2010. View at Google Scholar | View at Publisher

[4]          A. Jeyasankar, K. Elumalai, N. Raja, and S. Ignacimuthu, "Effect plant chemicals on oviposition deterrent and ovicidal activities against female moth, Spodoptera litura (Fab.) (Lepidoptera: Noctuidae)," International Journal of Agricultural Science and Research, vol. 2, pp. 206-213, 2013. View at Google Scholar 

[5]          B. Kiran Gandhi, R. H. Patil, and Y. Srujana, "Field resistance of spodoptera litura (Fab.) to conventional insecticides in India," Crop Protection, vol. 88, pp. 103-108, 2016. View at Google Scholar | View at Publisher

[6]          C. H. Ulrichs, I. Mews, and S. Adhikary, "Bhattacharyya A,  Goswami A. Antifeedant activity and toxicity of leaf extracts from Portesia coarctata Takeoka and their effects on the physiology of Spodoptera litura (F.)," Journal of Pest Science, vol. 81, pp. 79-84, 2008. View at Google Scholar | View at Publisher

[7]          K. Baskar, S. Kingsley, S. E. Vendan, M. Paulraj, and S. Ignacimuthu, "Antifeedant, larvicidal and pupicidal activities of Atalantia monophylla (L) Correa againstHelicoverpa armigera Hubner (Lepidoptera: Noctuidae)," Chemosphere, vol. 75, pp. 355-359, 2009. View at Google Scholar | View at Publisher

[8]          S. Ashouri and N. Shayesteh, "Insecticidal activities of black pepper and red pepper in powder form on adults of Rhyzopertha dominica (F.) and Sitophilus granarius (L.)," Pakistan Entomologist, vol. 31, pp. 122-127, 2009. View at Google Scholar 

[9]          A. Jeyasankar, T. Chinnamani, V. Chennaiyan, and G. Ramar, "Antifeedant activity of Barleria buxifolia (Linn.) (Acanthaceae) against Spodoptera litura fabricius and Helicoverpa armigera hübner(Lepidotera:Noctuidae)," International Journal of Natural Sciences Research, vol. 2, pp. 78 -84, 2014. View at Google Scholar 

[10]        M. B. Isman, O. Koul, A. Lucyzynski, and J. Kaminski, "Insecticidal and antifeedant bioactivities of neem oils and their relationship to azadirachtin content," Journal of Agricultural Food and Chemistry, vol. 38, pp. 1406-1411, 1990. View at Google Scholar | View at Publisher

[11]        T. Subramonithangam and K. Kathiresan, "Toxic effect of mangrove plant extracts on mosquito larvae Anopheles stephensi L.," Journal of Current Science, vol. 57, pp. 914-915, 1988. View at Google Scholar 

[12]        H. Ben Jannet, H. Skhiri, Z. Mighri, M. Simmonds, and W. Blaney, "Responses of spodoptera littoralis larvae to Tunisian plant extracts and to neo-clerodane diterpenoids isolated from Ajuga pseudoiva leaves," Fitoterapia, vol. 71, pp. 105 – 112, 2000. View at Google Scholar | View at Publisher

[13]        W. S. Abbott, "A method of computing the effectiveness of an insecticide," Journal of Economic Entomology, vol. 18, pp. 265-267, 1925. View at Google Scholar | View at Publisher

[14]        A. Jeyasankar, K. Elumalai, N. Raja, and S. Ignacimuthu, "Effect plant chemicals on oviposition deterrent and ovicidal activities against female moth, Spodoptera litura (Fab.) (Lepidoptera:Noctuidae)," International Journal of Agricultural Science, vol. 2, pp. 206-213, 2013. View at Google Scholar 

[15]        T. Chinnamani, R. Sivakami, and A. Jeyasankar, "Antifeedant, larvicidal and growth regulatory activities of fractions isolated from ethyl acetate extract of pseudocalymma alliaceum against Spodoptera litura Fabricius and Helicoverpa armigera Hübner (Lepidotera: Noctuidae)," International Journal of Advanced Research in Biological Sciences, vol. 3, pp. 98-107, 2016. View at Publisher

[16]        V. Chennaiyan, R. Sivakami, and A. Jeyasankar, "Evaluating ecofriendly botanicals of Barleria longiflora Linn. F. (Acanthaceae) against Armyworm Spodoptera litura Fab. and Cotton bollworm Helicoverpa armigera Hübner (Lepidoptera: Noctuidae)," Annual Research and Review in Biology, vol. 10, pp. 1-9, 2016. View at Publisher

[17]        A. Jeyasankar, N. Raja, and S. Ignacimuthu, "Antifeedant and growth inhibitory activities of syzygium lineare against Spodoptera litira(Lepidoptera: Noctuidae)," Current Research Journal of Biological Science, vol. 2, pp. 173–177, 2010. View at Google Scholar 

[18]        L. Lajide, P. Escoubas, and J. Mizutani, "Cyclohexadienones-insect growth inhibitors from the foliar surface and tissue extracts of Senecio cannabifolius," Experientia, vol. 52, pp. 259–263, 1996. View at Google Scholar | View at Publisher

[19]        K. Baskar, R. Maheswaran, S. Kingsley, and S. Ignacimuthu, "Bioefficacy of couroupita guianensis (Aubl) against Helicoverpa armigera (Hub.) (Lepidoptera: Noctuidae) larvae," Spanish Journal of Agricultural Research, vol. 8, pp. 135-141, 2010. View at Google Scholar | View at Publisher

[20]        K. Baskar and S. Ignacimuthu, "Ovicidal activity of Atalantia monophylla (L) Correa against Helicoverpa armigera Hubner (Lepidoptera: Noctuidae)," Journal of Agricultural Technology, vol. 8, pp. 861–868, 2012. View at Google Scholar 

Table-1.Antifeedant activity of ethyl acetate fractions of B.buxifoliaagainst fourth instars larvae of S.lituraand H.armigera

Fractions
Spodopteralitura
Helicoverpaarmigera
Concentrations tested (ppm)
125
250
500
1000
125
250
500
1000
I
7.56±3.08a
(15.89)
9.73±2.20a
(18.15)
10.38±2.22a
(18.72)
17.57±3.35a
(24.73)
8.25±3.64a
(16.64)
17.31±8.34bc
(24.58)
21.99±5.70b
(27.90)
26.35±7.49b
(30.85)
II
9.18±2.38ab
(17.56)
19.24±2.19b
(25.99)
19.64±4.35bc
(26.28)
24.85±4.37b
(29.87)
9.75±5.75a
(18.15)
12.30±5.19ab
(20.53)
13.92±7.72a
(21.89)
21.16±3.88a
(27.35)
III
21.10±4.02c
(27.35)
43.35±8.82c
(41.15)
59.42±7.31e
(50.42)
74.33±7.76e
(59.54)
23.73±4.73c
(29.13)
28.24±8.10c
(32.08)
43.99±7.41c
(41.50)
70.11±5.46e
(56.85)
IV
6.34±2.52a
(14.54)
9.46±1.62a
(17.85)
13.37±1.65ab
(21.39)
17.05±4.71a
(24.35)
12.24±9.70b
(20.44)
14.30±6.34b
(22.22)
15.66±7.49ab
(23.26)
20.84±7.06a
(27.13)
V
5.95±1.65a
(14.06)
13.06±4.54ab
(21.13)
22.35±6.26bc
(28.18)
28.76±8.39bc
(32.39)
6.36±3.56a
(14.54)
9.92±6.18a
(18.34)
11.51±5.26a
(19.82)
18.06±3.93a
(25.10)
VI
17.18±3.35b
(24.43)
27.88±7.94c
(31.82)
40.36±6.61d
(39.41)
57.32±11.35d
(49.20)
14.29±2.97bc
(22.14)
17.16±2.22bc
(24.43)
21.19±4.41b
(27.35)
50.43±7.06d
(45.23)
VII
8.83±2.75ab
(17.26)
14.18±7.08ab
(22.06)
16.45±4.78b
(23.89)
24.83±9.35b
(29.87)
7.65±3.82a
(16.00)
9.66±5.29a
(18.05)
12.76±3.47a
(20.88)
19.45±3.75a
(26.13)

Values are mean ±Standard deviation of five replications; Values in parentheses are angular transformed; ANOVA followed by Duncan Multiples Range Test (DMRT) was performed; Superscripts alphabet in the values are significantly different at p<0.05% Control group was fed with host plant without the treatment of chemicals.

Table-2.vicidal activity of ethyl acetate fractions of B.buxifoliaagainst fourth instars larvae of S.lituraand H.armigera

Fractions
Concentration (ppm)
S. litura
H. armigera
vicidal(%)
LC50
LC90
X2 value
Larvicidal (%)
LC50
LC90
X2 value
I
125
250
500
1000
9.30±1.30a
10.10±0.46a
16.30±1.30a
27.10±3.49a
1636.744
3031.141
0.571
7.20±1.35a
9.92±0.97a
12.60±1.43ab
17.10±2.77a
1585.015
2821.249
0.915
II
125
250
500
1000
10.42±1.13a
12.18±1.91a
18.90±3.57b
23.20±3.70ab
1873.519
3567.500
2.463
10.84±0.70a
13.60±1.98ab
19.06±3.40bc
29.50±2.47b
1508.466
2846.093
3.615
III
125
250
500
1000
34.38±6.32d
48.20±4.65d
54.10±4.00d
76.84±3.87d
437.466
1341.279
6.817
30.82±4.37c
46.14±2.77d
56.40±5.41e
73.12±2.48d
465.191
1422.692
5.801
IV
125
250
500
1000
9.60±2.30a
16.98±3.23b
20.54±3.90bc
28.42±4.46bc
1617.994
3172.792
3.302
9.48±1.79a
16.14±3.06bc
20.50±1.39c
27.00±3.78bc
1676.816
3272.828
3.412
V
125
250
500
1000
7.88±1.86a
9.12±1.73a
10.50±1.87a
28.88±2.92a
1569.626
2798.892
1.027
8.74±1.77a
9.42±0.98a
15.00±2.09a
26.40±3.65a
1695.320
3129.784
0.189
VI
125
250
500
1000
19.40±4.74c
26.02±4.18c
40.06±5.97c
62.06±2.37c
744.960
1672.508
1.081
19.12±5.80b
28.42±4.99c
48.42±2.97d
67.02±3.19c
1657.536
3174.053
1.136
VII
125
250
500
1000
12.18±5.05b
16.16±4.11b
20.64±3.14bc
29.20±4.45b
1689.712
3417.645
0.968
10.36±1.91a
13.88±2.05ab
16.88±2.58b
28.20±5.46b
650.405
1472.027
4.322

Values are mean ± S.D of five replication; Number of larvae =10; LC50=Lethal concentration 50 and LC90=Lethal concentration 90; SPSS16.0. Values with different alphabet in column are statistically significant (p<0.05 level; DMRT).

Table-3.Larvicidalctivity of ethyl acetate fractions of B.buxifoliaagainst fourth instars larvae of S.lituraand H.armigera.

Fractions
Concentration (ppm)
S. litura
H. armigera
Larvicidal (%)
LC50
LC90
X2 value
Larvicidal (%)
LC50
LC90
X2 value
I
125
250
500
1000
8.60±1.14a
12.80±2.41a
17.8±1.87a 28.48±1.46a
1519.723
2791.434
3.127
8.90±2.84a
12.40±2.06b
18.20±2.58ab
26.70±4.40bc
1620.130
3025.912
2.392
II
125
250
500
1000
9.40±1.24a
16.40±2.51ab
20.30±1.63b
31.30±1.27ab
1422.045
2699.516
4.918
15.90±2.57b
21.20±3.81bc
22.80±2.48b
28.40±2.99c
1650.628
3346.041
3.759
III
125
250
500
1000
21.80±1.85b
30.20±2.88d
51.20±7.09d
78.60±1.61d
549.205
1198.750
4.317
27.10±4.52d
39.30±8.12d
51.30±3.10c
73.70±4.05d
531.660
170.776
4.784
IV
125
250
500
1000
9.40±2.07a
15.60±3.07a
16.50±3.78a
37.30±4.29a
1264.146
2335.574
3.623
9.10±0.43a
10.30±0.54a
14.00±1.93a
26.80±3.22a
1633.267
2238.010
1414
V
125
250
500
1000
12.10±2.75ab
17.70±1.86b
18.10±2.26a
41.00±2.06a
1185.616
2246.520
5.313
11.10±1.47ab
13.60±2.06a
16.80±4.54a
23.80±5.44b
1616.643
3136.691
1.045
VI
125
250
500
1000
21.60±1.20b
35.70±7.87c
47.10±2.87c
68.20±3.98c
619.307
1494.693
4.715
20.80±1.08c
30.90±3.88c
50.70±5.65c
58.80±4.43c
736.127
1767.499
5.290
VII
125
250
500
1000
10.70±1.95a
15.80±2.80a
20.20±3.78ab
23.00±0.76b
1961.831
3896.151
3.419
13.30±2.26a
19.40±2.41bc
24.20±6.25bc
31.30±4.98bc
1561.350
3254.332
2.846

Values are mean ± S.D of five replication; Number of larvae =10; LC50=Lethal concentration 50 and LC90=Lethal concentration 90; SPSS16.0. Values with different alphabet in column are statistically significant (p<0.05 level; DMRT).