Biological Impacts of Various Metarhizium anisopliae Formulations on the Invasive Fall Armyworm, Spodoptera frugiperda
摘要
The fall armyworm (FAW), Spodoptera frugiperda (J. E. Smith), poses a significant threat to maize worldwide due to its voracious feeding nature and increasing resistance to conventional insecticides. Management of this pest with a single technique is often uneconomical and needs an alternative strategy for effective control. The current study investigates the efficacy of different oil-based formulations of the entomopathogenic fungus, Metarhizium anisopliae against S. frugiperda. The study utilized M. anisopliae formulation with various oils, such as groundnut, cottonseed, safflower, sunflower, sesame, soybean, and rice bran oils. Key attributes of S. frugiperda were measured including larval mortality, pupal duration, pupation rates, pupal weight, pupal and adult malformations, adult emergence, fecundity and longevity. Results demonstrated that rice bran oil-based formulations exhibited the highest efficacy, with the lowest LC50 values (46.67 mg/mL) for the larval stage, followed by sesame (59.44 mg/mL), sunflower (63.34 mg/mL) and safflower oil (67.37 mg/mL). Oil-based formulations, particularly those with rice bran oil, significantly influenced the development of S. frugiperda by extending larval (19.80 days) and pupal duration (13.80 days), reducing pupal weight (0.80 gm) and increasing malformations rate (66.70%). Furthermore, adult longevity and fecundity (266 eggs) were significantly decreased compared to untreated control. Ultimately, rice bran oil formulations displayed promising results by causing high mortality and significantly disrupting the biology of S. frugiperda. These findings suggest the rice bran oil based M. anisopliae can be used as a prominent biopesticide for the sustainable management of this destructive pest.