Background Tetranychus urticae Koch, is a globally significant agricultural pest. Its rapid development of resistance to conventional acaricides poses a major challenge to effective control. Recently, nanotechnology has emerged as a transformative approach in agriculture, particularly through the synthesis of eco-friendly nanoparticles using natural plant extracts. This study evaluates the acaricidal efficacy of silver nanoparticles (AgNPs) synthesized from Solanum elaeagnifolium unripe fruit extract against adult females of T. urticae. Characterization via UV-Vis, FT-IR, DLS, TEM, and zeta potential analysis confirmed the formation of stable, well-dispersed AgNPs. Results The reaction color of silver nanoparticles (AgNPs) from pale-brown to dark brown indicated that the nanoparticles were successfully formed. TEM image of silver nanoparticles (AgNPs) exhibited spherical shapes with a zeta potential of − 11.8 mV. The results indicated an increasing trend of mortality percentage along with the increasing concentrations of silver nanoparticles (AgNPs) synthesized from unripe S. elaeagnifolium fruit extract. Silver nanoparticles of synthesized from unripe S. elaeagnifolium were significantly effective against T. urticae. The highest mortality 85 ± 0.20% was observed for 20 µg/mL concentration after 72 h. Whereas, lowest mortality percentage were recorded 5 ± 0.78 and 10 ± 0.35% respectively after 24 h at concentrations 5 and 10 (µg/mL). Also, the average number of immature stages produced by the surviving T. urticae females were sharply decreased after treatment with varying concentrations of silver nanoparticles (AgNPs) synthesized from unripe S. elaeagnifolium fruits. The LC50 value dropped significantly from 25.559 µg/mL after 24 h while, reaching its lowest value of 8.937 µg/mL after 72 h of exposure. A similar decreasing trend was observed for LC90 values, which declined from 80.788 µg/mL (24 h) to 44.669 µg/mL (72 h) against T. urticae. The toxicity index was recorded 100% and The Resistance Ratio (RR) = (1.00) after 72 h of treatment. T. urticae exhibited an RR value of 2.86 at 24 h. Biochemically, silver nanoparticles (AgNPs) at 20 µg/mL significantly inhibited acetylcholinesterase (AChE) activity, while glutathione-S-transferase (GST) levels increased significantly after 72 h. Docking findings demonstrated that S. elaeagnifolium-mediated AgNPs support a possible role of enzymatic disruption (AChE and GST) of T. urticae. The components of unripe S. elaeagnifolium fruits were analyzed using gas chromatography–mass spectrometry (GC–MS). The major constituents are oleic acid, 13-octadecenoic acid, Z-2-tridecen-1-ol and Z, Z-2,5-pentadecadien-1-ol and α-tocopherol. Conclusion Prolonged exposure ensures continuous absorption and accumulation of the active ingredients of plant extract within the biological system of T. urticae, shifting the individuals from a state of relative tolerance at 24 h to complete susceptibility at 72 h. This study proved that application of silver nanoparticles synthesized from unripe S. elaeagnifoliumat fruits high concentrations and over extended exposure durations could be effective for control of T. urticae population. These results provided baseline data regarding the lethal thresholds of the silver nanoparticles of synthesized from S. elaeagnifolium, reinforcing its potential as a highly potent for targeted pest management strategy. S. elaeagnifolium-mediated silver nanoparticles (AgNPs) exhibit strong acaricidal activity against T. urticae through enzymatic disruption mechanisms. The IC50 value obtained for Vero cells was approximately 24–68-fold higher than the LC50 values recorded against mite, demonstrating a favorable safety margin and selective toxicity of the synthesized silver nanoparticles (AgNPs) toward the target mite relative to mammalian cells. These findings suggest that S. elaeagnifolium-mediated silver nanoparticles (AgNPs) serve as a potent and sustainable biopesticide for managing T. urticae populations. Graphical abstract

Acaricidal activity of silver nanoparticles biosynthesized from unripe fruits of Solanum elaeagnifolium Cav. against Tetranychus urticae Koch

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2026年8月2日

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Salwa M. El-Sayed,
Amany M. Ahmed,
Heba M. Emam

摘要

Background

Tetranychus urticae Koch, is a globally significant agricultural pest. Its rapid development of resistance to conventional acaricides poses a major challenge to effective control. Recently, nanotechnology has emerged as a transformative approach in agriculture, particularly through the synthesis of eco-friendly nanoparticles using natural plant extracts. This study evaluates the acaricidal efficacy of silver nanoparticles (AgNPs) synthesized from Solanum elaeagnifolium unripe fruit extract against adult females of T. urticae. Characterization via UV-Vis, FT-IR, DLS, TEM, and zeta potential analysis confirmed the formation of stable, well-dispersed AgNPs.

Results

The reaction color of silver nanoparticles (AgNPs) from pale-brown to dark brown indicated that the nanoparticles were successfully formed. TEM image of silver nanoparticles (AgNPs) exhibited spherical shapes with a zeta potential of − 11.8 mV. The results indicated an increasing trend of mortality percentage along with the increasing concentrations of silver nanoparticles (AgNPs) synthesized from unripe S. elaeagnifolium fruit extract. Silver nanoparticles of synthesized from unripe S. elaeagnifolium were significantly effective against T. urticae. The highest mortality 85 ± 0.20% was observed for 20 µg/mL concentration after 72 h. Whereas, lowest mortality percentage were recorded 5 ± 0.78 and 10 ± 0.35% respectively after 24 h at concentrations 5 and 10 (µg/mL). Also, the average number of immature stages produced by the surviving T. urticae females were sharply decreased after treatment with varying concentrations of silver nanoparticles (AgNPs) synthesized from unripe S. elaeagnifolium fruits. The LC₅₀ value dropped significantly from 25.559 µg/mL after 24 h while, reaching its lowest value of 8.937 µg/mL after 72 h of exposure. A similar decreasing trend was observed for LC₉₀ values, which declined from 80.788 µg/mL (24 h) to 44.669 µg/mL (72 h) against T. urticae. The toxicity index was recorded 100% and The Resistance Ratio (RR) = (1.00) after 72 h of treatment. T. urticae exhibited an RR value of 2.86 at 24 h. Biochemically, silver nanoparticles (AgNPs) at 20 µg/mL significantly inhibited acetylcholinesterase (AChE) activity, while glutathione-S-transferase (GST) levels increased significantly after 72 h. Docking findings demonstrated that S. elaeagnifolium-mediated AgNPs support a possible role of enzymatic disruption (AChE and GST) of T. urticae. The components of unripe S. elaeagnifolium fruits were analyzed using gas chromatography–mass spectrometry (GC–MS). The major constituents are oleic acid, 13-octadecenoic acid, Z-2-tridecen-1-ol and Z, Z-2,5-pentadecadien-1-ol and α-tocopherol.

Conclusion

Prolonged exposure ensures continuous absorption and accumulation of the active ingredients of plant extract within the biological system of T. urticae, shifting the individuals from a state of relative tolerance at 24 h to complete susceptibility at 72 h. This study proved that application of silver nanoparticles synthesized from unripe S. elaeagnifoliumat fruits high concentrations and over extended exposure durations could be effective for control of T. urticae population. These results provided baseline data regarding the lethal thresholds of the silver nanoparticles of synthesized from S. elaeagnifolium, reinforcing its potential as a highly potent for targeted pest management strategy. S. elaeagnifolium-mediated silver nanoparticles (AgNPs) exhibit strong acaricidal activity against T. urticae through enzymatic disruption mechanisms. The IC₅₀ value obtained for Vero cells was approximately 24–68-fold higher than the LC₅₀ values recorded against mite, demonstrating a favorable safety margin and selective toxicity of the synthesized silver nanoparticles (AgNPs) toward the target mite relative to mammalian cells. These findings suggest that S. elaeagnifolium-mediated silver nanoparticles (AgNPs) serve as a potent and sustainable biopesticide for managing T. urticae populations.

Graphical abstract