DIFFERENTIAL SUSCEPTIBILITY OF LABORATORY AND FIELD STRAINS OF Spodoptera littoralis BOISD (LEPIDOPTERA: NOCTUIDAE) TO INSECT GROWTH REGULATORS

Ali, Ola S.; Nasr, Hoda M.; Rabea, Entsar; Abd Elrasoul, Mona A.; Singab, Mohamed

doi:10.21608/jaesj.2025.406072.1281

DIFFERENTIAL SUSCEPTIBILITY OF LABORATORY AND FIELD STRAINS OF Spodoptera littoralis BOISD (LEPIDOPTERA: NOCTUIDAE) TO INSECT GROWTH REGULATORS

Document Type : Full research articles

Authors

¹ Department of Resistance, Central Agricultural Pesticides Laboratory, Agricultural Research Center, 12618 Giza, Egypt

² Department of Plant Protection, Faculty of Agriculture, Damanhour University, Egypt

10.21608/jaesj.2025.406072.1281

Abstract

The cotton leafworm, Spodoptera littoralis (Boisd.), has a significant impact on crop yields worldwide. To combat these losses, various management strategies have been developed. This study aimed to assess the efficacy of several commercial insect growth regulators (IGRs); lufenuron, diflubenzuron, hexaflumuron, flufenoxuron, and triflumuron against 4^th instar larvae of both laboratory and field strains of S. littoralis. The effects of these IGRs on key enzymes, including acetylcholinesterase (AChE), carboxylesterases (α- and β-esterases), and chitinase, in the same larval instars and strains were also examined. The results revealed that lufenuron was most toxic to the laboratory strain (LC₅₀: 1.47 mg/L), while diflubenzuron proved most potent against the field strain (LC₅₀: 3.78 mg/L). Furthermore, diflubenzuron was the most effective overall, evidenced by a reduction in the AChE activity and an increase in α-esterase activity. Lufenuron significantly boosted β-esterase activity, and both flufenoxuron and hexaflumuron led to a notable increase in chitinase activity.

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