Bio-residual activity of selected biopesticides in comparison with the conventional insecticide Dursban against cotton leafworm, Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae).
Pesticides play a central role in controlling major economic pests. There are many insecticides used today for controlling pests included organophosphorus (OP), carbamate, pyrethroids, and now modern neonicotinoid insecticides [1-6]. Pesticide resistance is widespread in many pests not only that, but also there are many cases of OP and carbamate resistance have been recorded in economic pests . Such an extensive reliance on conventional pesticides for pest control is expected to lead to the eventual rise in broad-spectrum resistances that could make many of the conventional pesticides ineffective [8, 9]. In this regards, it is very important to reduce the use of chemical pesticides that considered too risky to the environmental impacts and anticipate pesticide alternatives . One of the significant alternative pesticides is Spinosad [11-13].
Spinosad is a biologically derived insecticide produced via fermentation culture of the actinomycete Saccharopolyspora spinosa, a bacterial organism isolated from soil [14-17]. In view of its mode of action, Spinosad has novel mode of action that affects the nicotinic acetylcholine receptors (nAChRs) and the y-amino butyric acid (GABA) receptor physiology in the nervous system [18, 19]. However, the unique mode of action, physical and chemical properties, and environmental fate make Spinosad an excellent tool for management of insect pests [20-22].
In the study, we have made attempts to assess the bio-residual activity of 3 biopesticides, SpinTor (Spinosad), Echotech Bio (Bacillus thuringiensis sub.sp. kurstaki), and Neemix (Azadirachtin) in comparison with Dursban (an OP pesticide) on 2nd and 4th instars larvae of S. littoralis after 24 and 48 h feeding.
Materials and Methods
Egg masses were collected from different localities in Assiut Governorate, Egypt and reared under laboratory conditions the same as the laboratory strain that described .
The second and fourth instars larvae of S. littoralis were used for evaluation.
1. SpinTor 24 SC at a rate of 70 ml/100 L (Spinosad).
2. Ecotech Bio (32000 inter. unit) at a rate of 100 g/100 L (Bacillus thuringiensis subsp. kurstaki).
3. Neemix 4.5% at a rate of 100 ml/100 L (Azadirachtin).
4. Dursban 48% EC at rate of 500 ml/100 L (Chloropyrifos ethyl).
The formulation of SpinTor obtained from Dow Agroscience Co. Cairo office. Ecotech Bio was obtained from Ministry of Agriculture, Egypt. Neemix and Dursban were purchased from the commercial market.
Cotton, Giza 83 variety, was planted in the experimental farm of Faculty of Agriculture, Assiut University, Egypt.
For each compound, four plots (1/400 fed.) of cotton plants were sprayed with the rate mentioned before. All products were sprayed by using knabsack Sprayer of 20 L size. Treated leaves were taken at periods from 0 to 14 days after spray and transferred to the laboratory for feeding.
For each compound, 4 plastic cups were used. Each cup was provided with treated leaves and ten 2nd instar or five 4th instar larvae. Four cups were provided with cotton leaves treated with water only as control. The mortality was recorded 24 and 48 h after feeding the larvae. Percentage of mortality was estimated to each compound at different periods (from 0 to 14 days after spray). The dead larvae were recorded 24 and 48 h after exposure and the percentage of mortality was estimated and corrected according to Abott's formula .
Bioassay data were pooled and analyzed (the [LT.sub.50], [LT.sub.90], and 95% Confidence limits values) according to the methods described by Litchfield and Wilcoxon and Swaroop et al. [25, 26].
Results and Discussions
The [LT.sub.50] values of the four compounds tested after 24 h on 2nd instar larvae were 9.2, 6.4, 1.1 and 1.8 day for Dursban, SpinTor, Ecotech Bio, and Neemix, respectively (Table 1). According to the [LT.sub.90] value, Dursban was the highest 5.2 days followed by SpinTor 4.5 days whereas Ecotech Bio and Neemix showed the least values 0.16 and 0.17 days. Comparing the slope values, Neemix and Ecotech Bio had the highest slope values (6.06 and 4.29 days) indicating that the field strain of S. littoralis showed high degree of homogeneity in its response to these two compounds as compared with Dursban and SpinTor.
However, the [LT.sub.50] values of the four compounds tested after 48 h feeding experiments were 12, 9, 37, and 5 days for Dursban, SpinTor, Ecotech Bio, and Neemix, respectively (Table 2). Also, Dursban showed the highest [LT.sub.90] value (7.3 day), followed by SpinTor (5.5 days), whereas Ecotech Bio and Neemix exhibited the least [LT.sub.90] values (0.8 day for each). According to [LT.sub.50] and [LT.sub.90] values of the four compounds in 48 h feeding test, SpinTor showed the highest active compound among the three natural products tested against 2nd instar larvae of S. littoralis.
Generally, in both 24 and 48 h feeding test and according to the percentage of mortality and [LT.sub.50] and [LT.sub.90] values, Dursban showed the longest residual effect against 2nd instar larvae of S. littoralis followed by SpinTor, whereas, Ecotech Bio, and Neemix showed the shortest residual effects.
The [LT.sub.50] and [LT.sub.90] values after 24 h exposure tested on 4th instar larvae were 6, 3, 1-2 days, and 38, 0.8 and 0.1 for Dursban, SpinTor, and Neemix, respectively (Table 3). According to the percentage of mortality and to [LT.sub.50] and [LT.sub.90] values SpinTor showed the highest residual effect against 4th instar larvae among the three natural products tested. Comparing the slope values, 4th larvae of S. littoralis showed high homogeneity response to Neemix (7.28) followed by Spinosad (2.83) and lastly Dursban (1.3).
The [LT.sub.50] values of 4th instar larvae after 48 h feeding exposure, were 7.8, 4, and 3.2 days for Dursban, SpinTor, and Neemix, respectively (Table 4), the [LT.sub.90] values in respective were 4.0, 1.0, and 0.8 days. The slope values for the three compounds showed that 4th instar larvae exhibited high homogeneity response to Neemix (3.4) then SpinTor (2.87) and lastly Dursban (1.66).
According to the percentage of mortality and [LT.sub.50] and [LT.sub.90] values, Dursban exhibited the highest toxicity and longest residual effect against 4th instar larvae of S. littoralis, followed by SpinTor, whereas Neemix was of medium toxicity and residual effect. However, Ecotech Bio showed no toxicity (Table 4).
All in all, the 4 compounds tested showed variable degrees of efficacy and residual toxicity against both 2nd and 4th instars larvae of S. littoralis after 24 or 48 h feeding on treated leaves. The conventional insecticide Dursban showed the highest toxic and the longest residual effect irrespective of instar of feeding period. However, SpinTor was the highest active and had the longest residual effect among the three natural products tested.
Liu et al.  found in laboratory studies that SpinTor was highly toxic to 3rd instar larvae of the Cabbage looper, Trichoplusia ni for at least 36 days. However, Sanders and Bret (1997)  stated that in the laboratory and other protected environments, leaf residue of SpinTor has longer residual effect on the foliage as compared with that in the field conditions since the photolysis is the primary route of Spinosad degradation.
In interested work, Temerak  studied the residual activity of Dursban (500 ml/100 L), SpinTor (70 ml/100 L),
Dipel (100g/100L) and Neemix (100 ml/100L) on field strain of S. littoralis collected from Bohira Governorate, Egypt. In agreement with the present findings he found that Dursban and Spinosad after 48 h feeding gave 100% kill to the 2nd instar larvae up to the 9th and 7th day after treatment, and the toxicity of these two compounds extended as more than 50% kill was achieved after 11 day of spray. Based on result of the 2nd and 4th instars, the descending order of performance or the residual effect was Chlorpyrifos-ethyl, Spinosad, Neemix, and Dipel.
Comparing the speed of kill for the four compounds tested in the present study it might be concluded that Spinosad acts quickly and has speed of kill comparable to most synthetic insecticides (Dursban). It acts significantly faster than slow-acting products like Bacillus bacteria and other traditional biological. Bret et al.  attributed the high speed of kill of Spinosad to its contact and ingestion activity. Temerak  found that Spinosad follow Chlorpyrifos-ethyl, and superior to Neem and Dipel in its speed of kill against 2nd and 4th instars larvae of S. littoralis.
In conclusion, the three biopesticides tested, SpinTor, Neemix and Biotech bio showed variable degree of toxicity against S. littoralis. According to the present investigation and the available literature, Spinosad proved to be the most active biopesticide against cotton pests. Its efficacy was comparable to the synthetic insecticides in that it is equivalent to pyrethroid and superior to most carbamate pesticides . The Bt formulation (Biotech bio) and neem formulation (Neemix) showed low toxicity against Cotton leafworm and cotton bollworms. Further investigation of the biochemical and molecular biology of the mode of action should be done. Plus, more potent Spinosad analogs must be developed in the future to enhance the pesticide effectiveness and potency.
Published Online 10 March 2015.
Corresponding Author: Mohamed A.I. Ahmed, Plant Protection Department, Faculty of Agriculture, Assiut University, Assiut 71526, Egypt.
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[1.] Ahmed, M.A.I., F. Matsumura, 2012. Synergistic action of formamidine insecticides on the activity of pyrethroids and neonicotinoids against Aedes aegypti (Diptera: Culicidae). Journal of Medical Entomology, 49(6): 1405-1410.
[2.] Ahmed, R.M. Saba, 2014. Comparative toxicological evaluation between different formulations of two selected neonicotinoid pesticides on Culex pipiens (Diptera: Culicidae) mosquito. Advances of Environmental Biology, 8(4): 1169-1174.
[3.] Ahmed, M.A.I., S.A. Eraky, M. Fakeer, A.S. Soliman, 2014. Toxicity assessment of selected neonicotinoid pesticides against the sand termite, Psammotermes hypostoma Desneux workers (Isoptera: Rhinotermitidae) under laboratory conditions. Australian Journal of Basic & Applied Sciences, 8(9): 238-240.
[4.] Ahmed, M.A.I., 2014. Evaluation of novel neonicotinoid pesticides against Cotton leafworm, Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae) under laboratory conditions. Advances of Environmental Biology, 8(10): 1002-1007.
[5.] Ahmed M.A.I., C.F.A. Vogel, F. Matsumura, 2015. Unique biochemical and molecular biological mechanism of synergistic actions of formamidine compounds on selected pyrethroid and neonicotinoid insecticides on the fourth instar larvae of Aedes egypti (Diptera: Culicidae). Pesticide Biochemistry and Physiology. In press.
[6.] Ahmed, M.A.I., C.F.A. Vogel, 2015. Synergistic action of octopamine receptor agonists on the activity of selected novel insecticides for control of dengue vector Aedes aegypti (Diptera: Culicidae) mosquito. Pesticide Biochemistry and Physiology. In press.
[7.] Ahmed, M.A.I., A. Cornel, B. Hammock, 2012. Monitoring of Insecticide Resistance of Culex pipiens (Diptera: Culicidae) Colonies-Collected from California. International Journal of Environmental Science and Development, 3(4): 346-349.
[8.] Ahmed, M.A.I., N.S. Khalil, T.A. Abd El Rahman, 2014a. Determination of Pesticide Residues In Potato Tuber Samples Using QuEChERS Method With Gas Chromatography. Australian Journal of Basic & Applied Sciences, 8(3): 349-353.
[9.] Ahmed, M.A.I., N.S. Khalil, T.A. Abd El Rahman, 2014b. Carbamate pesticide residues analysis of potato tuber samples using high-performance liquid chromatography (HPLC). Journal of Environmental Chemistry and Ecotoxicology, 6(1): 1-5.
[10.] El-Geddawy, A.M.H., M.A.I. Ahmed, S.H. Mohamed, 2014. Toxicological Evaluation of Selected biopesticides and one essential oOil in comparison with Indoxacarb pesticide on Cotton leafworm, Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae) under laboratory conditions. American-Eurasian Journal of Sustainable Agriculture, 8(2): 58-64.
[11.] Sagri E., M. Reczko, M.E. Gregoriou, K.T. Tsoumani, N.E. Zygouridis, K.D. Salpea, F.G. Zalom, J. Ragoussis, K.D. Mathiopoulos, 2014. Olive fly transcriptomics analysis implicates energy metabolism genes in spinosad resistance. BMC Genomics, 15: 714.
[12.] Ekesi S., S. Mohamed, C.M. Tanga, 2014. Comparison of food-based attractants for Bactrocera invadens (Diptera: Tephritidae) and evaluation of mazoferm-spinosad bait spray for field suppression in mango. Journal of Economic Entomology, 107(1): 299-309.
[13.] Campos M.R., A.R. Rodrigues, W.M. Silva, T.B. Silva, V.R. Silva, R.N. Guedes, H.A. Siqueira, 2014. Spinosad and the tomato borer Tuta absoluta: a bioinsecticide, an invasive pest threat, and high insecticide resistance. PLoS One, 9(8): e103235.
[14.] Mertz, F.P., R.C. Yao, 1990. Saccharopolyspora spinosa sp. nov. isolated from soil collected in a sugar rum still, International Journal of Systematic Bacteriology, 40: 34-39.
[15.] Kirst, H.A., K.H. Michel, J.S. Mynderse, E.H. Chao, R.C. Yao, W.M. Nakatsukasa, L.D. Boeck, J. Occlowitz, J.W. Paschel, J.B. Deeter, G.D. Thompson, 1992. Discovery, isolation and structure elucidation of a family of structurally unique fermentation-derived tetracyclic macrolides. In: Baker, D.R., Fenyes, J.G., Steffens, J.J. (Eds.), Synthesis and Chemistry of Agrochemicals, Vol. 3. American Chemical Society, Washington, D.C., USA, pp: 214-225.
[16.] Sparks, T.C., G.D. Thompson, L.L. Larson, H.A. Kirst, O.K. Jantz, T.V. Worden, M.B. Hertlein, J.D. Busacca, 1995. Biological characteristics of the spinosyns: new naturally derived insect control agents. In: Proceedings of the Beltwide Cotton Conference, San Antonio, Texas, 4-7 January, 1995. National Cotton Council of America, Memphis, TN, USA, pp: 903-907.
[17.] Sparks, T.C., G.D. Thompson, H.A. Kirst, M.B. Hertlein, J.S. Mynderse, J.R. Turner, T.V. Worden, 1999. Fermentation-derived insect control agents. In: Hall, F.R., Menn, J.J. (Eds.), Biopesticides: Use and Delivery. Humana Press, Totowa, New Jersey, USA, pp: 171-188.
[18.] Salgado, V.L., 1998. Studies on the mode of action of spinosad: insect symptoms and physiological correlates. Pesticide Biochemistry and Physiology, 60: 91-102.
[19.] Salgado, V.L., T.C. Sparks, 2005. The spinosyns: Chemistry, biochemistry, mode of action and resistance. In: Gilbert, L.I., Iatrou, K., Gill, S. (Eds.), Comprehensive Insect Molecular Science. Elsevier B.V., 6: 137-173.
[20.] Biondi, A., V. Mommaerts, G. Smagghe, E. Vinuela, L. Zappala, N. Desneux, 2012. The non-target impact of spinosyns on beneficial arthropods. Pest Management Science, 68(12): 1523-1536.
[21.] Cleveland, C.B., 2007. Environmental and health assessments for spinosad against the backdrop of organic certification. In: Felsot, A.J., Racke, K.D. (Eds.), Certified Organic and Biologically-Derived Pesticides: Environmental, Health, and Efficacy Assessment. Symposium Series. American Chemical Society, Washington D.C., USA, pp: 109-130.
[22.] Racke, K.D., 2007. A reduced risk insecticide for organic agriculture. In: Felsot, A.J., Racke, K.D. (Eds.), Certified Organic and Biologically-Derived Pesticides: Environmental, Health, and Efficacy Assessment. Symposium Series. American Chemical Society, Washington D.C., USA, pp: 92-108.
[23.] Ahmed, M.A.I., S.A.S. Temerak, F.A. Abdel Galil, S.H.M. Manna, 2015. Effect of selected host plants on the efficacy of spinosad pesticide on Cotton leafworm, Spodoptera littoralis (Boisd.) (Lepidoptera: Noctuidae) under laboratory conditions. Advances in Environmental Biology, In press.
[24.] Abbott, W.S., 1925. A method of computing the effectiveness of an insecticide. Journal of Economic Entomology, 18: 265-267.
[25.] Litchfield, J.J., F. Wilcoxon, 1949. A simplified method of evaluation dose-effect experiments. Journal of Pharmacology and Experimental Therapeutics, 96: 99-113.
[26.] Swaroop, S., A.B. Gilory, K. Umeura, 1966. Susceptibility tests. Statistical methods in malaria eradication. WHO Monograph Seris, No. 5, WHO, Geneva, pp: 118-129.
[27.] Liu, T.X., A.N. Sparks, W.H. Hendrix, B. Yue, 1999. Effects of spintor (spinosad) on cabbage looper (Lepidoptera: Noctuidae): Toxicity and persistence of leaf residue on cabbage under field and laboratory conditions. Journal of Economic Entomology, 92(6): 1266-1273.
[28.] Saunders, D.G., B.L. Bret, 1997. Fate of spinosad in the environment. Down to Earth, 52(1): 14-20.
[29.] Temerak, S.A., 2002. Historical records of Cotton leafworm (Spodoptera littoralis) resistance to conventional insecticides in the field as influenced by the resistance programs in Egypt from 1950-2002. Resistant Pest management Newsletter, 12(1): 7-10.
[30.] Bret, B.L., L.L. Larson, J.R. Schoonover, T.C. Sparks, G.D. Thompson, 1997. Biological properties of spinosad. Down To Earth, 52(1): 6-13.
(1) Mohamed A.I. Ahmed, (1) Farouk A. Abdel-Galil, (1) Sobhy A.H. Temerak, (1) Samir H.M. Manna
(1) Plant Protection Department, Faculty of Agriculture, Assiut University, Assiut 71526. Egypt
Table 1: Probit analysis parameters of Dursban and 3 biopesticides tested against 2nd instar larvae of S. littoralis after 24 h feeding. Compounds [LT.sub.50] Confidence limits Slope (days) Upper Lower Dursban 9.2 9.9 8.55 1.56 SpinTor 6.4 6.76 6.06 1.28 Neemix 1.8 2.31 1.4 6.06 Ecotech bio 1.1 1.51 0.8 4.29 Compounds [LT.sub.90] Confidence limits (days) Upper Lower Dursban 5.2 5.6 4.83 SpinTor 4.5 4.75 4.26 Neemix 0.17 0.22 0.13 Ecotech bio 0.16 0.22 0.12 Table 2: Probit analysis parameters of Dursban and 3 biopesticides tested a gainst 2nd instar larvae of S. littoralis after 48 h feeding. Compounds [LT.sub.50] Confidence limits Slope (days) Upper Lower Dursban 12 12.9 11.16 1.33 Spinosad 9 9.92 8.16 1.47 Neemix 5 6.69 3.74 4.08 Ecotech bio 3.7 4.98 2.75 3.33 Compounds [LT.sub.90] Confidence limits (days) Upper Lower Dursban 7.3 7.85 6.26 Spinosad 5.5 6.06 4.99 Neemix 0.8 1.07 0.6 Ecotech bio 0.8 1.08 0.59 Table 3: Probit analysis parameters of Dursban and 3 biopesticides tested against 4th instar larvae of S. littoralis after 24 h feeding. Compounds [LT.sub.50] Confidence limits Slope days Upper Lower Dursban 6 6.57 5.8 1.39 SpinTor 3 4 2.25 2.83 Neemix 1.2 1.91 0.63 7.28 Ecotech bio No toxicity Compounds [LT.sub.90] Confidence limits days Upper Lower Dursban 3.8 4.16 3.47 SpinTor 0.8 1.07 0.6 Neemix 0.1 0.16 0.06 Ecotech bio No toxicity Table 4: Probit analysis parameters of Dursban and 3 biopesticides tested against 4th instar larvae of S. littoralis after 48 h feeding. Compounds [LT.sub.50] Confidence limits Slope days Upper Lower Dursban 7.8 8.87 6.86 1.66 SpinTor 4 5.36 2.99 2.87 Neemix 3.2 4.18 2.45 3.4 Ecotech bio No toxicity Compounds [LT.sub.90] Confidence limits days Upper Lower Dursban 4 4.55 3.52 SpinTor 1 1.34 0.75 Neemix 0.68 0.89 0.52 Ecotech bio No toxicity
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|Title Annotation:||Research Article|
|Author:||Ahmed, Mohamed A.I.; Abdel-Galil, Farouk A.; Temerak, Sobhy A.H.; Manna, Samir H.M.|
|Publication:||American-Eurasian Journal of Sustainable Agriculture|
|Date:||Jan 1, 2015|
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