Efficiency of nano-emulsion of propolis with activator adjuvants in improving the pesticide application technology on eggplant leaves

Abstract

Most conventional pesticide formulations get lost in the field during spraying, which causes a variety of issues with the environment and public health. Therefore, the study aimed to use new nanotechnology, such as nanoemulsion of propolis (NP) alone or mixed with some activator adjuvants, tannin (T), argal (Si), and urea (U) for improving the performance of chlorfenapyr on eggplant leaves. The results of the study indicate that the addition of chlorfenapyr to NP alone or in combination with the tested activator adjuvants reduced the surface tension of chlorfenapyr, improved the total initial amounts of droplet deposition efficiency, gradually enhanced the translocation process from soil to the eggplant leaves and between the leaves, and increased the efficiency of chlorfenapyr at the lowest dose while reducing environmental contamination. After two hours of treatment, the droplet deposition efficiency of chlorfenapyr on the eggplant leaves was found to be improved by NP alone at a concentration of 0.25 % to 1.58 mg kg⁻¹, as compared to 1.05 mg kg⁻¹ in the control. However, when NP was combined with activator adjuvants, NP-Si-U, the droplet deposition efficiency was increased to 1.90 mg kg⁻¹. Furthermore, chlorfenapyr enhanced with NP-Si-U induced the highest control efficiency against Tetranychus urticae. It is evident that treating chlorfenapyr amended with NP-T-U and NP-Si-U on the middle eggplant leaves, separately induced considerable translocation the pesticides to other part of the eggplant leaves within the range of 0.12 mg kg⁻¹ – 0.23 mg kg⁻¹, and 0.13 mg/kg⁻¹ − 0.27 mg/kg⁻¹, respectively through 1–3 days, while it did not transfer in the chlorfenapyr alone. Moreover, the transfer of chlorfenapyr from the soil to eggplant leaves increased, with values ranging between 0.63–0.79 mg/kg⁻¹ and 0.65–0.96 mg/kg⁻¹, respectively, during 2–4 days of exposure compared to 0.22–0.31 mg/kg⁻¹ in chlorfenapyr. The addition of NP to chlorfenapyr improved the plants vigor index for tomato, squash, and sweet melon to 1.23, 1.18, and 1.11 times at the recommended dose, and to 1.40, 1.50, and 1.32 times at half the recommended dose, respectively compared with the control. These results suggest that the addition of NP with activator adjuvants to pesticides leads to improvements in control efficiency and efficacy of utilization.