Comparative toxicological analysis of different plant leaf extracts from diverse families targeting rice moth, Corcyra cephalonica (Lepidoptera: Pyralidae)

Introduction

Insect infestation in storage facilities remains a critical challenge in agriculture. Insects contribute to 5% of the total 10% grain damage caused by pests annually [1] , resulting in substantial financial losses [2] . While chemical pesticides remain in use, growing concerns about food safety have prompted the development of eco-friendly pest management approaches [3,4] . These alternative strategies include plant-derived insecticides, biological control agents such as Bacillus thuringiensis (Bt), entomopathogenic fungi, natural enemies, and semiochemicals for controlling C. cephalonica and similar stored product pests [5][6][7][8][9] . The stored grain pest Corcyra cephalonica (Stainton), commonly known as the rice moth, belongs to the order Lepidoptera. The pest has established its presence across Europe, Africa, Asia, and North America [10] , with ongoing spread to new territories through grain trade and transportation of infested products. The larvae cause significant damage by feeding on broken and damaged cereal grains, creating characteristic silk webbing that eventually forms dense masses, binding the infested products together [11] . The infestation not only damages the grain but also reduces its commercial value due to contamination with insect waste, silk webs, shed skins, and dead insects. Despite its significant impact, the destructive potential of C. cephalonica is often undervalued [12] . Enhanced understanding of this pest's impact and biology is crucial for developing effective management strategies. Additionally, the simplicity and costeffectiveness of rearing C. cephalonica in laboratory conditions make it an attractive option for producing biological control agents. This aspect is particularly relevant for developing nations where the high costs often limit the implementation of biological control programs [13] . The present investigation deals in exploring the biocontrol potential of plant botanicals belonging to 12 different families viz.,Sapotaceae (Achrassapota, Sapota), Annonaceae (Annona squamosa, Custard apple), Umbelliferae (Annethumsowa, Dill) Chenopodiaceae (Chenopodium album, Lamb's quarters), Euphorbiaceae (Euphorbia nerifolia, Palsetia), Moraceae (Ficusindica, Banyan and Ficusreligiosa, Peepal), Rutaceae (Murrayakoenigii, Curry leaf tree), Combretaceae (Quisqualisindica, Ragoon creeper), Myrtaceae (Syzygiumcumini, Black plum), Apocynaceae (Tabernaemontanalivaricate, Chandani) Caesalpiniaceae (Tamarindusindica, Tamarind tree)) and Papilionaceae (Trogonellafoenum-graecum, Fenugreek) against larvae of C. cephalonica (Stainton) in an experimentation designed for analysis of toxicological studies including anti-feeding and repellent action.

Materials and Methods

Culturing and Rearing of Insects

The culture of the experimental insect C. cephalonica was obtained from Agricultural Research Station, Durgapura, Jaipur. In laboratory, the stock culture was maintained in transparent glass jars. These jars were pre-sterilized by keeping them at 60 °C for 24 hours in an oven. The rearing of insects was done on artificial diet comprising sterilized half-crushed sorghum at 50-60 °C for a period of 2 days with 10% of brewer'syeast added to the diet mixture.

Collection of Plant Botanicals

The experimentation was devised in two phases. During first phase the botanicals were collected from open fields of Agricultural Research Station, Durgapura, Jaipur. The fresh leaves were collected, dried and solvent extracted in soxhlet assembly [14] , with a mantle heating temperature of 50 °C. The thimble comprised of Whatmann filter paper No. 80 holding 30 gram powdered sample of each of the plant extract. The running time was standardized to a period of 11 hours.

Toxicological Studies

The toxicological studies were done by assessing the antifeeding and larvicidal action. For the assessment of antifeeding action of plant extracts, the insect diet (5 gram sorghum) was treated with 1 ml extract having four different concentrations (25, 50, 75 and 100%) with three replications of each concentration tested against C. cephalonica larvae. The solvent was itself used as control deprived of plant extracts in plastic vials used for experimentation. A total of twenty 3 rd instar larvae were utilized under each concentration for a 20 day observation period. The loss in seed weight of sorghum was compared with control diet calculated by C-value [15] .

Percentseedprotectionovercontrol =

% seed protection in treated -% seed protection in control 100 -% seedprotectionincontrol x 100

Where, A is average loss in seed weight in experimental trial and M is average loss in seed weight in control

The repellent properties were estimated using Y-shaped olfactometer [16] . The 20 newly emerged adults were released in the center of olfactometer through the base arm.

The repellency percentage was calculated [17] .

RepellencyPercentage = Insects in control arm -Insects in experimental arm Insectsincontrolarm x 100

The petroleum ether and acetone were used as solvents destined for control.

Results

The highest anti-feeding potential was recorded for A. squamosa against C. cephalonica with a 87.80% of percent seed protection @100% concentration while least antifeeding potential was recorded with Q. indica (56.91% @ 25% concentration) among 9 different plants (Table 1). The repellent action of plant leaf extracts against C. cephalonica was assessed using two different solvents, represented in Table 2. The least effect was observed for T. indica petroleum ether extract and highest effect was observed for T. livaricate petroleum ether extract.

Discussions

The results in the current finding are in consonance with the observations recorded by previous research groups. It is observed that neem plant extract exhibited highest antifeeding property against Perical liaricini and Selepadocilis [18] . Three new flavonoidshave been isolated from the roots of Tephrosia emoroides and reported their anti-feeding activity against the larvae of spotted borer, Chilo partellus [19] . Also, 4 neem products (azadirachtin, azadirachtiniodine, neem seeed oil cake and neem oil) has been evaluated and found that all exhibited potent anti-feeding activity against rice moth, C. cephalonica [20] . Phago deterrent action of M. koenigii, A. sapota and A. sowa leaf extract were evaluated [21] . They registered 84.26, 62.44 and 51.86% seed protection @ 100% concentration respectively with the above mentioned plant leaf extracts. These findings for anti-feeding potential are in agreement with the present investigation. Similarly, for repellent potential, the present investigation withholds to the previous studies [22] , where they reported 100 percent repellency of C. cephalonica when adults were subjected to citrus clean oil formulation. Highest repellent properties of C. album (petroleum ether extracts) against tobacco cutworm, Spodoptera litura larvae has been found [23] . The results obtained [24] , also in accordance with the present investigation where they reported high repellent potential of A. sowa against Tribolium castaneum. In near future the emphasis should be on these plant derived safe to environment biochemicals so as to attain the goal of sustainable agriculture. Moreover, the Gas-Chromatography (GC-MS) analysis and High Performance Liquid Chromatography (HPLC) studies are required so as to decipher the biochemistry of the metabolites responsible for insect deterring potential.

Acknowledgement

AcknowledgementsThe authors are thankful to Dean and HoD, Department of Zoology, University of Rajasthan, Jaipur for their invaluable support during the research work for the research facilities.The authors are also thankful to Dean, College of Agriculture, GBPUA&T, Pantnagar.

References

1. Yuksel E, Canhilal R, Imren M. Potential of four Turkish isolates of entomopathogenic nematodes against three major stored products insect pests. J. Stored Prod. Res. 2019;83:317-321.
2. Urrutia RI, Yeguerman C, Jesser E, Gutierrez VS, Volpe MA, Gonzalez JOW. Sunflower seed hulls waste as a novel source of insecticidal product: pyrolysis biooil bioactivity on insect pests of stored grains and products. J. Clean. Prod. 2021;287:125-132.
3. Kumar D, Kalita P. Reducing postharvest losses during storage of grain crops to strengthen food security in developing countries. Foods. 2017;6(1):8.
4. Arthur FH. Structural pest management for stored product insects. In: Recent Advances in Stored Product Protection. Springer, Berlin, Heidelberg; 2018. p. 6581.
5. Jhala J, Vyas A, Swami H, Mordia A. Efficacy of different plant products against rice moth (Corcyra cephalonica, Stainton) in rice. J. Entomol. Zool. Studies. 2018;6(4):1109-1112.
6. Prashant K, Saravanan L. Insecticidal activity of Bacillus thuringiensis strains against rice grain moth, Corcyra cephalonica. Int. J. Plant Protect. 2008;1(2):66-68.
7. Ahmad MJ, Pathania SS, Sajad M. Laboratory evaluation of anthocorid predator, Blaptostethus pallescens against storage pest, Corcyra cephalonica in rice. J. Exp. Zool. India. 2007;20(2):897-900.
8. Paul AVN, Srivastava M, Dureja P, Singh AK. Semiochemicals produced by tomato varieties and their role in parasitism of Corcyra cephalonica (Lepidoptera: Pyralidae) by the egg parasitoid Trichogramma chilonis (Hymenoptera: Trichogrammatidae). Int. J. Trop. Insect Sci. 2008;28(2):108-116. https://doi.org/10.1017/S1742758408977493.
9. Jhala J, Vyas AK, Rajput VS, Sharma S. Biology of (Corcyra cephalonica, Stainton) on different host. J. Pharmacogn. Phytochem. 2019;8(5):476-479.
10. Shazali MEH, Smith RH. Life history studies of externally feeding pests of stored sorghum: Corcyra cephalonica (Staint.) and Tribolium castaneum (Hbst). J. Stored Prod. Res. 1986;22(2):55-61.
11. Meena BL, Jeengar KL, Singh B, Meena NL. Evaluation of different plant powders as seed protectants against rice moth, Corcyra cephalonica Stainton. J. Appl. Nat. Sci. 2016;8(2):910-918.
12. Wang QY, Dong X, Yang J, Hu YH, Peng LQ, Zheng H, Cao J. Vesicle-based ultrasonic-assisted extraction of saponins in Panax notoginseng. Food Chem. 2020;303:125-134.
13. Kogan M, Goeden RD. The host-plant range of Lematrilinae daturaphila (Coleoptera: Chrysomelidae). Ann. Entomol. 1970;63(4):1175-1180.
14. Read DP, Feeny PP, Root RB. Habitat selection by the aphid parasite Diaeretiella rapae (Hymenoptera: Braconidae) and hyperparasite Charips brassicae (Hymenoptera: Cynipidae). Can. Entomol. 1970;102(12):1567-1578.
15. Granett P, Haynes HL, Connola DP, Bowery TG, Barber GW. Two butoxypolypropylene glycol compounds as fly repellents for livestock. Ann. Entomol. 1949;42(2):281-286.
16. Jacob S, Sheila MK. A note on the protection of stored rice from the lesser grain borer, Rhizopertha dominica Fabr. by indigenous plant products. Indian J. Entomol. 1993;55(3):337-339.
17. Machocho AK, Lwande W, Jondikoa JI, Moreka LVC, Hassanali A. Three new flavonoids from the root of Tephrosia emoroides and their antifeedant activity against the larvae of the spotted stalk borer Chilo partellus Swinhoe. Int. J. Pharmacogn. Pharm. Res. 1995;33(3):222-227.
18. Chakkraborti S, Chatterjee M. Effects of neem derivatives in survival, growth, and development of the rice moth, Corcyra cephalonica (Stainton). Pest Management and Economic Zoology. 1996;4(1-2):3743.
19. Dwivedi SC, Venugopalan S. Olfactory response of Callosobruchus chinensis (Linn.) to the odours of six plant extracts. J. Adv. Zool. 2002;23(2):77-79.
20. Dwivedi SC, Garg S. Oviposition deterrent properties of some plant extracts against rice moth, Corcyra cephalonica (Stainton). Uttar Pradesh J. Zoo. 2002;20(2):191-193.
21. Dwivedi SC, Mathur B. Screening of plant extracts as repellents against Spodoptera litura (Fabricius). Indian Bio. 2000;32(1):71-73.
22. Tripathi AK, Veena P, Aggarwal SPS, Kumar. Toxicity of fractionated essential oil from Anethum sowa seed towards castaneum Herbst. J. Med. Aromat. Plant Sci. 2001;22(4):146-150.