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<p>Botanical insecticides are a&#xa0;promising alternative for integrated pest management programs, with neem derivatives (<i>Azadirachta indica</i> (Meliaceae)) being the most widespread and widely used, with different commercial formulations available on the Brazilian market. However, inconsistent results have been observed in the field, which may be due to variations in the qualitative and quantitative profile of the active compounds in these formulations. Therefore, the aim of this study was to evaluate the content of azadirachtin (the majority limonoid) in four commercial formulations based on neem limonoids available on the Brazilian market (Agroneem®, Fitoneem®, Azamax® and Azact® EC) and to compare their lethal and sublethal toxicity to <i>Spodoptera frugiperda</i> (Lepidoptera: Noctuidae) larvae using toxicological parameters. At the diagnostic concentration (5.000 mg&#xa0;kg<sup>−1</sup>), all the formulations tested caused significant lethal toxicity (Azact® EC (LC<sub>50</sub> = 160.5 mg&#xa0;kg<sup>−1</sup>), Fitoneem® (LC<sub>50</sub> = 198.3 mg&#xa0;kg<sup>−1</sup>), Azamax® (LC<sub>50</sub> = 700.5 mg&#xa0;kg<sup>−1</sup>) and Agroneem® (LC<sub>50</sub> = 1115.3 mg&#xa0;kg<sup>−1</sup>)); however, these mortality levels were lower than those observed in the positive control consisting of a&#xa0;chlorantraniliprole-based insecticide (Premio® 200 g&#xa0;L<sup>−1</sup>&#xa0;a. i.; LC<sub>50</sub> = 18.4 mg&#xa0;kg<sup>−1</sup>). In addition to lethal toxicity, the limonoid-based formulations also caused significant inhibition of larval development in a&#xa0;concentration-dependent manner (Azact® EC (EC<sub>50</sub> = 160.5 mg&#xa0;kg<sup>−1</sup>), Fitoneem® (EC<sub>50</sub> = 110.7 mg&#xa0;kg<sup>−1</sup>), Azamax® (EC<sub>50</sub> = 275.1 mg&#xa0;kg<sup>−1</sup>) and Agroneem® (EC<sub>50</sub> = 285.4 mg&#xa0;kg<sup>−1</sup>)) without differing between them based on comparison of the confidence intervals of the adjusted values. UHPLC/MS/MS analysis indicated a&#xa0;wide variation in the azadirachtin content between the formulations tested. Our results indicated that the levels of lethal and sublethal toxicity observed in these limonoid-based formulations may contribute to the management of <i>S.&#xa0;frugiperda</i>, keeping populations below levels that cause economic damage and providing alternatives for controlling resistance problems.</p>

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Azadirachtin Content and Comparative Toxicity of Commercial Formulations Based on Limonoids on Spodoptera frugiperda (Lepidoptera: Noctuidae)

  • 期刊论文

  • 发表日期：

    2025年8月22日

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  • Liliane Nachtigall Martins,
  • Fernanda Carla dos Santos Geisler,
  • Dylan Thomas Telles Amandio,
  • Matheus Rakes,
  • José Djair Vendramim,
  • Moacir Rossi Forim,
  • Michele Trombin de Souza,
  • Mireli Trombin de Souza,
  • Leandro do Prado Ribeiro,
  • Daniel Bernardi

摘要

Botanical insecticides are a promising alternative for integrated pest management programs, with neem derivatives (Azadirachta indica (Meliaceae)) being the most widespread and widely used, with different commercial formulations available on the Brazilian market. However, inconsistent results have been observed in the field, which may be due to variations in the qualitative and quantitative profile of the active compounds in these formulations. Therefore, the aim of this study was to evaluate the content of azadirachtin (the majority limonoid) in four commercial formulations based on neem limonoids available on the Brazilian market (Agroneem®, Fitoneem®, Azamax® and Azact® EC) and to compare their lethal and sublethal toxicity to Spodoptera frugiperda (Lepidoptera: Noctuidae) larvae using toxicological parameters. At the diagnostic concentration (5.000 mg kg−1), all the formulations tested caused significant lethal toxicity (Azact® EC (LC50 = 160.5 mg kg−1), Fitoneem® (LC50 = 198.3 mg kg−1), Azamax® (LC50 = 700.5 mg kg−1) and Agroneem® (LC50 = 1115.3 mg kg−1)); however, these mortality levels were lower than those observed in the positive control consisting of a chlorantraniliprole-based insecticide (Premio® 200 g L−1 a. i.; LC50 = 18.4 mg kg−1). In addition to lethal toxicity, the limonoid-based formulations also caused significant inhibition of larval development in a concentration-dependent manner (Azact® EC (EC50 = 160.5 mg kg−1), Fitoneem® (EC50 = 110.7 mg kg−1), Azamax® (EC50 = 275.1 mg kg−1) and Agroneem® (EC50 = 285.4 mg kg−1)) without differing between them based on comparison of the confidence intervals of the adjusted values. UHPLC/MS/MS analysis indicated a wide variation in the azadirachtin content between the formulations tested. Our results indicated that the levels of lethal and sublethal toxicity observed in these limonoid-based formulations may contribute to the management of S. frugiperda, keeping populations below levels that cause economic damage and providing alternatives for controlling resistance problems.