Entomopathogenic Fungi-Mediated AgNPs: Synthesis and Insecticidal Effect against Plutella xylostella (Lepidoptera: Plutellidae)

Tárcio S Santos; Camila de Souza Varize; Elena Sanchez-Lopez; Sona A Jain; Eliana B Souto; Patrícia Severino; Marcelo da Costa Mendonça

doi:10.3390/ma15217596

Entomopathogenic Fungi-Mediated AgNPs: Synthesis and Insecticidal Effect against Plutella xylostella (Lepidoptera: Plutellidae)

Materials (Basel). 2022 Oct 28;15(21):7596. doi: 10.3390/ma15217596.

Authors

Tárcio S Santos¹, Camila de Souza Varize², Elena Sanchez-Lopez^{3

4

5}, Sona A Jain^{1

6}, Eliana B Souto^{3

7

8}, Patrícia Severino^{1

6}, Marcelo da Costa Mendonça^{1

2

6}

Affiliations

¹ Post-graduate Program in Industrial Biotechnology (PBI), University Tiradentes (Unit), Av. Murilo Dantas, 300, Aracaju 49010-390, Brazil.
² Sergipe Agricultural Development Company (Emdagro), Av. Carlos Rodrigues da Cruz s/n, Aracaju 49081-015, Brazil.
³ Department of Pharmacy, Pharmaceutical Technology and Physical Chemistry, Faculty of Pharmacy and Food Sciences, University of Barcelona, 08028 Barcelona, Spain.
⁴ Institute of Nanoscience and Nanotechnology (IN2UB), University of Barcelona, 08028 Barcelona, Spain.
⁵ Unit of Synthesis and Biomedical Applications of Peptides, IQAC-CSIC, 08034 Barcelona, Spain.
⁶ Institute of Technology and Research (ITP), Av. Murilo Dantas, 300, Aracaju 49010-390, Brazil.
⁷ Department of Pharmaceutical Technology, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal.
⁸ REQUIMTE/UCIBIO, Faculty of Pharmacy, University of Porto, Rua de Jorge Viterbo Ferreira, 228, 4050-313 Porto, Portugal.

Abstract

The insect Plutella xylostella is known worldwide to cause severe damage to brassica plantations because of its resistance against several groups of chemicals and pesticides. Efforts have been conducted to overcome the barrier of P. xylostella genetic resistance. Because of their easy production and effective insecticidal activity against different insect orders, silver nanoparticles are proposed as an alternative for agricultural pest control. The use of entomopathogenic fungi for nanoparticle production may offer additional advantages since fungal biomolecules may synergistically improve the nanoparticle's effectiveness. The present study aimed to synthesize silver nanoparticles using aqueous extracts of Beauveria bassiana, Metarhizium anisopliae, and Isaria fumosorosea isolates and to evaluate their insecticidal activity against P. xylostella, as innovative nano-ecofriendly pest control. The produced silver nanoparticles were evaluated by measuring the UV-vis spectrum and the mean particle size by dynamic light scattering (DLS). I. fumosorosea aqueous extract with 3-mM silver nitrate solution showed the most promising results (86-nm mean diameter and 0.37 of polydispersity). Scanning electron microscopy showed spherical nanoparticles and Fourier-Transform Infrared Spectroscopy revealed the presence of amine and amide groups, possibly responsible for nanoparticles' reduction and stabilization. The CL₅₀ value of 0.691 mg mL^-1 was determined at 72-h for the second-instar larvae of the P. xylostella, promoting a 78% of cumulative mortality rate after the entire larval stage. From our results, the synthesis of silver nanoparticles mediated by entomopathogenic fungi was successful in obtaining an efficient product for insect pest control. The I. fumosorosea was the most suitable isolate for the synthesis of silver nanoparticles contributing to the development of a green nanoproduct and the potential control of P. xylostella.

Keywords: agricultural pest control; biological control; biological synthesis; entomopathogenic fungi; silver nanoparticles.

Grants and funding

CAPES/Coordination for the Improvement of Higher Education Personnel