Dose-Reduction Potential of Spinosad via Combination with Green-Synthesized Silver Nanoparticles for Thrips Control

The green synthesis of nanoparticles offers a solution to control pesticide-resistant pests while minimizing environmental and health risks. Thrips tabaci is an injurious pest that attacks garlic crops and spreads the Iris yellow spot virus. The present research was performed to evaluate the synergistic effects of silver nanoparticles (AgNPs) synthesized by Teucrium polium with Spinosad against T. tabaci and assess their impact on garlic photosynthetic pigments. The characterization of the prepared nanoparticles was carried out by SEM, XRD, and Malvern zeta sizer. Antimicrobial activity was assessed using microdilution. Photosynthetic pigments were measured with a spectrophotometer after treating garlic cloves with four different concentrations of AgNPs and Spinosad mixture along with positive control (Spinosad) and negative control (tap water). Toxic bioassays were conducted under laboratory, greenhouse, and open field conditions. The results indicate all treatments, except for the 100% AgNPs, resulted in 100% second instar larvae and adult mortality after 72 h in the laboratory. In greenhouse conditions, the 50% Spinosad–50% AgNPs achieved 93.85% larvae mortality, and the 75% Spinosad–25% AgNPs achieved 100% adult mortality after a week. In open field conditions, the combination 50% Spinosad–50% AgNPs showed high efficacy, resulting in 65.97% mortality of larvae and 73.06% mortality of adults after 72 h. This study reveals that AgNPs have active pesticide properties against T. tabaci with minimal environmental and health risks.