Mortality Responses of Helicoverpa armigera (Lepidoptera: Noctuidae) against Different Insecticides under Laboratory Conditions

Muhammad Usman Asif1*, Sadam Hussain Soomro2, Raza Muhammad1, Sikandar Ali Soomro2

1Plant Protection Division, Nuclear Institute of Agriculture, Tandojam-70060, Pakistan

2Department of Entomology, Sindh Agriculture University, Tandojam, Pakistan

Abstract | Toxicity of five different insecticides viz., Uniron 10 EC, Bio Care TM 16000 IU/mg, Voliam Flexi 300 SC, Neomed 3 SC and Coragen 20 SC was recorded against 3rd instar larvae of Helicoverpa armigera under laboratory conditions at their low, recommended and high doses by leaf dip method. The results concluded that significantly high toxicity was shown after treatment with Neomed 3 SC which caused 100 % to the insect at its recommended (200 ml) and high dose (400 ml) after 24 hours of application followed by Voliam Flexi 300 SC causing 66.66 % and 75% mortality on its recommended (80 ml) and high dose (160 ml), respectively. After 72 hours, 83.33% mortality was observed in Voliam Flexi on its recommended dose whereas percent mortality was reached to 100% on its high dose. Uniron 10 EC was also found effective and statistically at par with Voliam Flexi 300 SC causing 100 % mortality at its recommended dose after 96 hours of exposure. However, Bio CareTM 16000 IU/mg consisting of Bacillus thuringiensis was least effective at its recommended dose with percent mortality of 25% and 41.66% after 72 and 96 hours, respectively. It is thus concluded that Neomed 3 SC is the most effective insecticide against 3rd instar larvae of H. armigera as compared to other tested insecticides.

Novelty Statement | This study reported the efficacy of newer synthetic insecticides in comparison with biopesticide containing Bacillus thruingiensis against Helicoverpa armigera.

Article History

Received: April 08,2020

Revised: May 6, 2020

Accepted: June 27, 2020

Published: July 14, 2020

Authors’ Contributions

MUA designed, conducted research, recorded data, drafted manuscript and analyzed the data. SHS executed the experiment, collected data and wrote the manuscript. RM finalize experimental plan, supervised the project and proof read the manuscript. SAS helped in execution of experiment and data collection.

Keywords

Amercian bollworm, Comparison, Gram, Insecticides, Mortality

Corresponding author: Muhammad Usman Asif, uakhan1987@hotmail.com

To cite this article: Asif, M.U., Soomro, S.H., Muhammad, R., Soomro, S.A., 2020. Mortality responses of Helicoverpa armigera (Lepidoptera: Noctuidae) against different insecticides under laboratory conditions. Punjab Univ. J. Zool., 35(2): 167-172. https://dx.doi.org/10.17582/journal.pujz/2020.35.1.167.172

Introduction

The genus Helicoverpa in the family Noctuidae consists of many significantly important pest species including H. zea, H. assulta, H. armigera and H. punctigera (Behere et al., 2007). Annual economic damage to crops due to the feeding of H. armigera is estimated to be in millions of dollars (Tabashnik et al., 2013; Smith-Pardo, 2014). This pest feeds on more than 180 plant species belonging to 45 different families including fibrous and food crops (Rauf et al., 2019). Successive generations due to high productiveness in addition to strong migratory potential, facultative diapause, resistance development phenomenon against insecticides enabled H. armigera to become most threatening and cosmopolitan pest of agriculture (Ahmad et al., 2004; Wakil et al., 2012).

Use of insecticides is the most efficient method of insect pest management all over the world. Worldwide usage of pesticide has increased manifold since the 1960s (Sheikh et al., 2011). In Pakistan, the dependence on pesticides is very much apparent from its fast growing trend of utilization, i.e. the import of pesticides increased from 13,030 tons in 1990 to 36,180 tons in 2011 (GOP, 2012).

Economic importance of crop yield compelled the growers to support the repeated usage of insecticides on alternate days, occasionally almost double the recommended doses (Babar et al., 2016). Now a day, synthetic chemicals like pesticides are being consumed in huge amount for the management of insect pest as compared to past (Rauf et al., 2019). This non-judicious and indiscriminate consumption has resulted into resistance development in numerous insect pests especially in H. armigera (Hamed et al., 2006).

In an effort to alleviate insecticide resistance, various tactics have been proposed and evaluated in the field and these novel techniques must be substantiated with pest control and economic data to satisfy growers. Key elements of resistance management include minimizing pesticide use, avoiding tank mixes, avoiding persistent chemicals, and using long-term rotations of pesticide from different chemical classes (Gressel et al., 1996; Bethke, 2010). With such strategies, resistance may be delayed or reduced by conserving adequate population of susceptible individuals through the usage of available pesticides at lower rates and avoidance in the selection of recessively resistant heterozygotes. Contrarily, use of pesticide at high dose is also suggested but only for reducing or eliminating occurrence of heterozygotes where resistance is dominant (Helps et al., 2017). Numerous studies have been carried out in this aspect with rodenticides and fungicides, while some were conducted against insects for resistance management by high/low dose strategy (Denholm and Rowland, 1992).

So far, this strategy has not been evaluated on the resistant population of H. armigera collected from field. The present studies report the comparative efficacy of different insecticides at low and high recommended field dose rate against H. armigera.

 

Materials and Methods

Insects rearing

Experiments were performed in maintained laboratory conditions at 25 + 20 C, 60 + 5% RH and 14-10 h (L:D) photoperiod. The larvae collected from chickpea crop grown at experimental farm of Nuclear Institute of Agriculture, Tandojam were brought to the laboratory and kept singly in the petri dishes (9 cm x 1.5 cm). Fresh leaves of gram were provided daily until pupation in clean petri dishes to avoid microbial contamination. Pupae were transferred to adult rearing jars (17 cm x 9 cm) for emergence. The adults on emergence were paired in the jars and covered with muslin cloth for mating and egg laying. The adults were supplied with 10% sugar solution. The muslin cloth was also provided at the surface of plastic jar to facilitate the females for egg laying. After hatching, larvae were transferred individually in petri dishes and provided fresh leaves of gram. Insecticidal treatments were applied on the homogeneous population of 3rd instar larvae acquired from F-1 generation.

Insecticides

Five different insecticides were tested against 3rd instar larvae of H. armigera. Three dosages i.e. recommended (mentioned on label), high (double of recommended) and low (half of recommended dose) of each insecticide were made by serial dilutions (Table 1).

Bioassay

Toxicity of five different insecticides was determined by using leaf dip method (Busvine, 1971). Fresh leaves of gram were immersed in insecticides solution for ten seconds. After air drying, treated leaves were put in petri dishes containing moistened blotting paper below to avoid dryness. Twelve third instar larvae of H. armigera were placed singly on treated leaves in petri dishes with four larvae per replicate. The treatments were replicated thrice. In control treatment, larvae were placed on leaves treated with water.

Statistical analysis

The data regarding percent mortality were recorded after 24, 48, 72 and 96 hours of treatment. Insects were considered dead with no apparent sign of life even when touched with a needle. Data on percent larval mortality were analyzed through one way ANOVA and means were compared by using LSD (Least Significant Difference) test at 5% probability level.

Table 1: Details of insecticides.

Tr.	Insecticides	Active ingredient	Doses (per acre)
			Low	Recommended	High
T1	Uniron 10 EC	Novaluron	150 ml	300 ml	600 ml
T2	Bio Care 16000 IU/mg	Bacillus thuringiensis	125 gm	250 gm	500 gm
T3	Voliam Flexi 300 SC	Thiamethoxam + Chlorantraniliprole	40 ml	80 ml	160 ml
T4	Neomed 3 SC	Emamectin benzoate + Lufenuron	100 ml	200 ml	400 ml
T5	Corgaen 20 SC	Chlorantraniliprole	25 ml	50 ml	100 ml
T6	Control

 

Results

Percent mortality at recommended doses

The results revealed significant difference in the mean percent mortality of the 3rd instar larvae of H. armigera after exposure to recommended doses at various time intervals (Table 2). After 24 hours, the maximum percent mortality of 100% was observed in Neomed followed by Voliam Flexi with percent mortality of 66.66%. However, no mortality was observed for Uniron, Bio Care and Coragen after 24 hours. After 48 hours, 41.66% and 8.33% mortality was recorded in Uniron and Coragen, respectively whereas it was constant in case of Voliam Flexi. Mortality after 72 hours increased significantly in four insecticides as 83.33 % for Volim Flexi and Uniron, 66.66% for Coragen and 25% for Bio Care. Uniron showed complete mortality (100%) after 96 hours followed by Voliam Flexi and Coragen with percent mortality of 91.66% and 83.33%, respectively. The lowest mortality of 41.66% was caused by Bio Care at its field recommended dose after 96 hours.

 

Table 2: Effect of recommended doses of insecticides on the larvae of H. armigera after different time intervals.

Tr.	Insecticides	Mean percent mortality
		After 24 hrs	After 48 hrs	After 72 hrs	After 96 hrs
T1	Uniron 10 EC	0 c	41.66 bc	83.33 a	100 a
T2	Bio Care 16000 IU/mg	0 c	0 d	25.00 b	41.66b
T3	Voliam Flexi 300 SC	66.66b	66.66 ab	83.33 a	91.66a
T4	Neomed 3 SC	100 a	100 a	100 a	100 a
T5	Corgaen 20 SC	0 c	8.33 cd	66.66 a	83.33a
T6	Control	0 c	0 d	0 b	0 c

 

Mean sharing similar letters in columns are not significantly different at p=0.05

 

Overall mean percent mortality comparison showed that maximum mortality (100%) was seen at the recommended dose of Neomed followed by Voliam Flexi and Uniron with percent mortality of 77.08% and 56.25%, respectively. However, Coragen and Bio Care caused 39.58% and 16.66% percent mortality, respectively and found least effective insecticides against larvae of H. armigera at their recommended dose rates (Figure 1).

Percent mortality at high doses

After 24 hours, the highest percent mortality of 100 % was recorded in Neomed followed by Voliam Flexi (75%). The lowest percent mortality was observed in Uniron (8.33 %) whereas no mortality was observed after treatment with Coragen and Bio Care. Mortality increased after 48 hours of exposure in four insecticide treatments as 83.33 % for Voliam Flexi, 58.33 % for Coragen, 50 % for Uniron and 25 % for Bio Care. Voliam Flexi showed complete mortality (100 %) after 72 hours followed by Coragen and Uniron with percent mortality of 91.66 % and 83.33 %, respectively. The lowest percent mortality of 33.33% was caused by Bio Care insecticide. After 96 hours, 100 % mortality was also reached in Uniron whereas Coragen and Bio Care showed 91.66 % and 41.66 %, respectively (Table 3).

 

Table 3: Effect of high doses (double of recommended) of insecticides on the larvae of H. armigera after different time intervals.

Tr.	Insecticides	Mean percent mortality
		After 24 hrs	After 48 hrs	After 72 hrs	After 96 hrs
T1	Uniron 10 EC	8.33 c	50 cd	83.33 a	100 a
T2	Bio Care 16000 IU/mg	0 c	25 de	33.33 b	41.66 b
T3	Voliam Flexi 300 SC	75 b	83.33 ab	100 a	100 a
T4	Neomed 3 SC	100 a	100 a	100 a	100 a
T5	Corgaen 20 SC	0 c	58.33 bc	91.66 a	91.66 a
T6	Control	0 c	0 e	0 c	0 c

 

Mean sharing similar letters in columns are not significantly different at p=0.05

 

Overall comparison of mean percent mortality at high dose revealed that Neomed was best by showing 100 % mortality of H. armigera followed by 89.58 % in Voliam Flexi, 60.41% in Coragen and Uniron, whereas Bio Care was least effective with 25 % mortality (Figure 2).

Percent mortality at low doses

Table 4 also showed significant toxicity variations among the evaluated insecticides at their low doses after 24, 48, 72 and 96 hours of exposure. No mortality was recorded for Uniron, Bio Care and Coragen after 24 hours of treatment whereas it was significantly high for Neomed followed by Voliam Flexi with percent mortality of 91.66% and 58.33%, respectively. After 48 hours, Neomed caused 100% mortality whereas slight increase in mortality was observed in Voliam Flexi (66.66%) and Coragen (8.33%). Mortality further increased after 72 hours of exposure in three treatments as 83.33 % for Voliam Flexi, 58.33 % for Coragen and 8.33 % for Uniron. No larval mortality was observed for Bio Care after 48 and 72 hours. After 96 hours, Voliam Flexi and Coragen showed 83.33% mortality followed by 58.33% in Uniron whereas Bio Care was least effective with percent mortality of 41.66%.

 

Table 4: Effect of low doses (half of recommended) of insecticides on the larvae of H. armigera after different time intervals.

Tr.	Insecticides	Mean percent mortality
		After 24 hrs	After 48 hrs	After 72 hrs	After 96 hrs
T1	Uniron 10 EC	0 c	0 c	8.33 c	58.33bc
T2	Bio Care 16000 IU/mg	0 c	0 c	0 c	41.66c
T3	Voliam Flexi 300 SC	58.33 b	66.66b	83.33a	83.33ab
T4	Neomed 3 SC	91.66 a	100 a	100 a	100 a
T5	Corgaen 20 SC	0 c	8.33 c	58.33b	83.33ab
T6	Control	0 c	0 c	0 c	0 d

 

Mean sharing similar letters in columns are not significantly different at p=0.05

The overall comparison of mean percent mortality at low doses of tested insecticides showed that Neomed was most effective against H. armigera by bringing about 97.91% mortality followed by Voliam Flexi (72.91%) and Coragen (37.5%). However, Uniron and Bio Care were least effective with percent mortality of 16.66% and 10.41%, respectively at their low dose rates (Figure 3).

 

Discussion

The present studies indicated that all the tested insecticides were found effective and caused significant mortality of 3rd instar larvae of H. armigera. Among the tested insecticides, Neomed 3 SC (emamectin benzoate + lufenuron) was the most effective insecticide by causing highest percent mortality followed by Voliam Flexi 300 SC (thiamethoxam + chloranraniliprole), Uniron 10 EC (novaluron) and Coragen 20 SC (chlorantraniliprole) at their recommended doses. Neomed is the combination of emamectin benzoate and lufenuron. Emamectin benzoate belongs to second-generation of avermectins having unique toxic potential against lepidopteran pests (Vargas et al., 1997). It acts as an activator of chloride channels by decreasing the neurons excitability. Soon after its exposure the insect stop feeding, larvae become paralyzed irreversibly and die (Cardwell et al., 2005). Lufenuron acts as a chitin synthesis inhibitor and effects the larval development of lepidopterans and also causes the infertile eggs production. Exposed insects fail to complete the moult due to the inhibition of the synthesis of new cuticle (Tunaz and Uygun, 2004). Our results are in agreement with Baikar and Naik (2016) who reported that emamectin benzoate caused highest percent mortality of H. armigera larvae and found best among the other treatments under laboratory conditions. Similarly, Babar et al. (2012) determined the larvicidal and ovicidal action of emamectin benzoate against H. armigera and recorded 96 % mortality in laboratory and reported it as the most effective larvicide. Likewise, Jat et al. (2016) recommended that for effective management of H. armigera, emamectin benzoate and spinetoram could be the first choice. Khatri et al. (2014) also observed lufenuron and flufenoxuron more effective compared to other two tested insect growth regulators against 3rd instar larvae of H. armigera. Akbar et al. (2018) reported significant mortality of larval population of H. armigera after application of emamectin benzoate (74.99%) and lufenuron (62.49%) with lower pod damage and enhanced yield. Iqbal et al. (2014); Babar et al. (2016) and Hakeem et al. (2017) confirmed the high toxicity of emamaectin benzoate and lufenuron against H. armigera in laboratory and field studies.

 

The present study have indicated that Voliam Flexi 300 SC was the second most effective insecticide and caused more than 90% mortality of H. armigera at its recommended dose. Voliam Flexi is the combination of chlorantraniliprole and thiamethoxam. Chlorantraniliprole belongs to anthranilic diamides with novel mode of action and acts as an activator of ryanodine receptors of insects causing rapid muscle paralysis and dysfunction (Cordova et al., 2006, 2007; Lahm et al., 2005, 2007). Thiamethoxam is a broad-spectrum systemic insecticide. It is rapidly absorbed and transported to all parts of the plants including pollen where it acts to deter insect feeding. It enters the insect body through direct contact or through stomach after feeding and also through its tracheal system. The compound disrupts the transfer of information between nerve cells by interfering with nicotinic acetylcholine receptors and ultimately paralyzes the insects muscles (FAO, 2014). These results are in line with the Rizvi and Jaffar (2015), who conducted a study to compare the biopesticide and synthetic insecticide on the development and growth of three different pests belonging to Noctuidae family. They concluded that Voliam Flexi 300 SC and Delegate 25 EC caused highest percentage mortality of H. armigera. Likewise, Abbas et al. (2015) also reported 89 % mortality of the target pests with Voliam Flexi.

The present results showed that Uniron 10 EC (novaluron) did not cause any larval mortality after 24 hours of exposure. These results are completely in line with Jat et al. (2016) who also concluded that insecticide novaluron did not show any promising results after 24 h feeding of 3rd instar H. armigera. Bio insecticide, Bio Care TM 16000 IU/mg that consists of Bacillus thuringiensis was found least effective with minimum mortality of tested insect. B. thuringiensis Cry and Cyt protein families are a diverse group of proteins with activity against insects of different orders-Lepidoptera, Diptera, Coleoptera, and also against other invertebrates such as nematodes. Their primary action is to lyse midgut epithelial cells by inserting into the target membrane and forming pores (Bravo et al., 2007). Similar to these findings, Baikar and Naik (2016)also observed only 11% mortality of H. armigera after treatment with B. turingiensis.

 

Conclusion

It can be inferred from the present study that insecticides Neomed 3 SC (emamectin benzoate + lufenuron) and Voliam Flexi 300 SC (thiamethoxam + chloranraniliprole) could be the first choice for management of H. armigera in field crops.

 

Conflict of interests

The authors have declared no conflict of interest.

 

References

Ahmad, S., Zia, K. and Shah, N.U.R., 2004. Chemical control of pod borers on chickpea. Int. J. Agric. Biol., 6: 978- 980.

Abbas, G., Hassan, N., Farhan, M., Haq, I. and Karar, H., 2015. Effect of selected insecticides on Helicoverpa armigera Hubner (Lepidoptera: Noctuidae) on tomato (Lycopersicon esculentum Miller) and their successful management. Adv. Entomol., 3: 1-23. https://doi.org/10.4236/ae.2015.31003

Akbar, W., Asif, M.U., Memon, R.M., Bux, M. and Sohail, M., 2018. Validation of some new chemistry and conventional insecticides against gram pod borer (Helicoverpa armigera) in chickpea. Pak. Entomol., 40: 45-49.

Babar, T.K., Hasnain, M., Aslam, A., Ali, Q., Ahmad, K.J., Ahmad, A. and Shahid, M., 2016. Comparative bioefficacy of newer insecticides against tomato fruit borer, Helicoverpa armigera (Hubner) on tomato crop under field conditions. Pak. Entomol., 38: 115-122.

Babar, K.S., Bharpoda, T.M., Shah, K.D. and Jhala, R.C., 2012. Bio-efficacy of newer molecules of insecticides against chickpea pod borer, Helicoverpa armigera (Hubner). AGRES (An International e- Journal), 1: 134-147.

Baikar, A.A. and Naik, K.V., 2016. Efficacy of insecticides against fruit borer, Helicoverpa armigera (Hubner) infesting chili under laboratory conditions. Pl. Arch., 16: 890-892.

Behere, G.T., Tay, W.T., Russell, D.A., Heckel, D.G., Appleton, B.R., Kranthi, K.R. and Batterham, P., 2007. Mitochondrial DNA analysis of field populations of Helicoverpa armigera (Lepidoptera: Noctuidae) and of its relationship to H. zea. BMC Evol. Biol., 7: 117-892. https://doi.org/10.1186/1471-2148-7-117

Bethke, J.A., 2010. UC IPM pest management guidelines: Floriculture and ornamental nurseries. University of California, Davis.

Bravo, A., Gill, S.S. and Soberon, M., 2007. Mode of action of Bacillus thuringiensis Cry and Cyt toxins and their potential for insect control. Toxicon, 49: 423-435. https://doi.org/10.1016/j.toxicon.2006.11.022

Busvine, J.R., 1971. A critical review of the techniques for testing of insecticides. 2nd ed. London: Commonwealth Agriculture Bureau.

Cardwell, G.E.E., Godfrey, L.D., Chaney, W.E. and Bentley, W.J., 2005. Various novel insecticides are less toxic to humans, more specific to key pests. Calif. Agric., 59: 29-34. https://doi.org/10.3733/ca.v059n01p29

Cordova, D., Benner, E.A., Sacher, M.D., Rauh, J.J., Sopa, J.S. and Lahm G.P., 2006. Anthranilic diamides: a new class of insecticides with a novel mode of action, ryanodine receptor activation. Pestic. Biochem. Physiol., 84: 196–214. https://doi.org/10.1016/j.pestbp.2005.07.005

Cordova, D., Benner, E.A., Sacher, M.D., Rauh, J.J., Sopa, J.S. and Lahm G.P., 2007. Elucidation of the mode of action of Rynaxypyr, a selective ryanodine receptor activator, in Pesticide Chemistry: Crop Protection, Public Health and Environmental Safety, Ed. by Ohkawa E, Miyagawa, H., Lee, P.W., Wiley-VCH, Weinheim, Germany.

Denholm, I. and Rowland, M.W., 1992. Tactics for managing pesticide resistance in arthropods: Theory and practice. Annu. Rev. Entomol., 37: 91-112. https://doi.org/10.1146/annurev.en.37.010192.000515

FAO, 2014. FAO specifications and evaluations for thiamethoxam. http://www.fao.org/ fileadmin/templates/agphome/documents/Pests_Pesticides/Specs/Thiamethoxam2014.pdf

Gressel, J., Gardner S.N. and Mangel, M., 1996. Prevention versus remediation in resistance management. In: molecular genetics and evolution of pesticide resistance, Chapter 18, pp. 169-186. ACS ACS Symposium Series, Vol. 645. American Chemical Society, Washington DC, USA. https://doi.org/10.1021/bk-1996-0645.ch018

GOP, 2012. Economic survey of Pakistan, 2011-2012. MINFAL., Islamabad, Pakistan. pp. 35-52. https://doi.org/10.1525/as.2012.52.1.100

Hakeem, S.A., Wani, R.A., Jahangeer, A., Baba, B.A., Allie, N.A., Bashir, S., Seerat-un-Nissa, Zaffer, G., Dar, S.A. and Yaseen, A., 2017. Evaluation of different insecticides against pod borer (Helicoverpa armigera) in lentil. Int. J. Curr. Microbiol. App. Sci., 6: 681- 685. https://doi.org/10.20546/ijcmas.2017.607.083

Hamed, M., Khan, R.A. and Jamil, F.F., 2006. Toxicity of different insecticide mixtures against cotton bollworm, Helicoverpa armigera (Hub.) (Lepidoptera: Noctuidae). Pakistan J. Zool., 38: 39-42.

Helps, J.C., Paveley, N.D. and Van Den Bosch, F., 2017. Identifying circumstances under which high insecticide dose increases or decreases resistance selection. J. Theor. Biol., 428: 153-167. https://doi.org/10.1016/j.jtbi.2017.06.007

Iqbal, J.S., Farooq, U., Jamil, M., Khan, H.A.A. and Younis, M., 2014. Relative efficacy of selective insecticides against gram pod borer (Helicoverpa armigera) of chickpea. Mycopathologia, 12: 119-122.

Jat, B.L., Yadav, S.S. and Lal, R., 2016. Bioassay of new chemistry insecticides against pod borer, Helicoverpa armigera on chickpea. Ind. J. Plant Prot., 44: 185-188.

Khatri, I., Shaikh, A.A., Sultan, R., Wagan, M.S. and Zubair, A., 2014. Effect of some insect growth regulators against gram pod borer Helicoverpa armigera (Hb.) on chickpea Cicer arietinum (L.) under laboratory conditions. Pakistan J. Zool., 46: 1537-1540.

Lahm, G.P., Selby, T.P., Freudenberger, J.H., Stevenson, T.M., Myers, B.J. and Seburyamo, G., 2005. Insecticidal anthranilic diamides: A new class of potent ryanodine receptor activators. Bioorg. Med. Chem. Lett., 15: 4898–4906. https://doi.org/10.1016/j.bmcl.2005.08.034

Lahm, G.P., Stevenson, T.M., Selby, T.P., Freudenberger, J.H., Cordova, D. and Flexner, L., 2007. Rynaxypyr: a new insecticidal anthranilic diamide that acts as a potent and selective ryanodine receptor activator. Bioorg. Med. Chem. Lett., 17: 6274–6279. https://doi.org/10.1016/j.bmcl.2007.09.012

Rizvi, S.A.H. and Jaffar, S., 2015. Efficacy of some selected chemical insecticides and bio-pesticides against tomato fruit worm, (Helicoverpa armigera) under the agro climatic condition of Gilgit Baltistan, Pakistan. J. Entomol. Zool. Stud., 3: 50-52.

Rauf, I., Javaid, S., Naqvi, R.Z., Mustafa, T., Amin, I., Mukhtar, Z., Jander, G. and Mansoor, S., 2019. In-planta expression of insecticidal proteins provides protection against lepidopteran insects. Sci. Rep., 9: 1-7. https://doi.org/10.1038/s41598-019-41833-7

Smith-Pardo, A., 2014. The old world bollworm Helicoverpa armigera (Hübner) (Lepidoptera: Noctuidae: Heliothinae) its biology, economic importance and its recent introduction into the western hemisphere. Bol. Mus. Entomol. Univ. Valle., 6: 18–28.

Sheikh, S.A., Nizamani, S.M., Jamali, A.A. and Kumbhar, M.I., 2011. Pesticides and associated impact on human health: A Case of small farmers in southern Sindh, Pakistan. J. Pharm. Nutr. Sci., 1: 82-86. https://doi.org/10.6000/1927-5951.2011.01.01.13

Tabashnik, B.E., Brevault, T. and Carriere, Y., 2013. Insect resistance to Bt crops: Lessons from the first billion acres. Nat. Biotechnol., 31: 510–521. https://doi.org/10.1038/nbt.2597

Tunaz, H. and Uygun, N., 2004. Insect growth regulators for insect pest control. Turk. J. Agric. For., 28: 377-387.

Vargas T, Garza-Urbina, A.P., Blanco-Montero, E., Perez-Carmona, C.A., Pellegaud G. and Rabago, J.M., 1997. Efficacy of new insecticides to control beet armyworm in north eastern Mexico. In: Proceedings of the Beltwide Cotton Conference of the National Cotton Council, New Orleans, Louisiana. pp. 1030-1031.

Wakil, W., Ghazanfar, U.M., Nasir, N., Qayyum, M.A. and Tahir, M., 2012. Insecticidal efficacy of Azadirachta indica, Nucleopolyhedrovirus and Chlorantraniliprole singly or combined against field populations for Helicoverpa armigera Hubner (Lepidoptera: Noctuidae). Chilean J. Agric. Res., 72: 53-61. https://doi.org/10.4067/S0718-58392012000100009