Synergism in Two-Component Insecticides with Dillapiole against Fall Armyworm

Area of Science:

• Agricultural Entomology
• Natural Product Chemistry
• Insecticide Development

Background:

• The fall armyworm (Spodoptera frugiperda) is a significant global pest threatening food security.
• Existing control methods (pyrethroids, organophosphorus, GM crops) face widespread resistance.
• Essential oils offer potential alternative pest control due to bioactive compounds and synergistic interactions.

Purpose of the Study:

• To evaluate the insecticidal activity of individual constituents from Piper aduncum essential oil.
• To investigate synergistic and antagonistic effects of binary mixtures of these constituents against fall armyworm.
• To explore novel, low-toxicity insecticide strategies leveraging essential oil component interactions.

Main Methods:

• Tested individual insecticidal activity of Piper aduncum essential oil constituents.
• Assessed insecticidal activity of binary mixtures of these constituents.
• Applied compounds topically to the dorsal pronotum of Spodoptera frugiperda larvae.

Main Results:

• Isolated dillapiole exhibited significant insecticidal activity (LD50 = 0.35 ppm).
• Binary mixtures of dillapiole with β-caryophyllene, methyl eugenol, and α-humulene showed strong synergistic effects (LD50s = 0.03–0.05 ppm).
• Antagonistic effects were observed in some mixtures, such as dillapiole + β-pinene (LD50 = 0.44 ppm).

Conclusions:

• Piper aduncum essential oil constituents possess potent insecticidal properties against the fall armyworm.
• Synergistic interactions between specific constituents can dramatically enhance insecticidal efficacy.
• Targeted binary mixtures offer a promising strategy for developing effective, low-environmental-impact insecticides.