Nanoscale hydroxyapatite-coated Cu-based nanopesticides exhibited promising benefits: enhanced application efficiency and plant element homeostasis

Abstract

Cu-based pesticides are globally popular owing to their low toxicity, high efficiency, broad applicability, and cost-effectiveness. Nevertheless, their use frequently results in waste accumulation and environmental concerns. Herein, we developed nanoscale hydroxyapatite as a Cu-based pesticide carrier and coated it with chitosan for achieving slow release of Cu/P. The HAP carriers with three sizes (20 nm, 60 nm, and 80 μm) and three types of Cu-based pesticides (OrganCu, InorganCu, and NanoCu) were prepared and compared. The nanopesticide (K60) prepared using the 60 nm HAP carrier and NanoCu commercial pesticide were proved with a particle size of less than 200 nm, and exhibited potential in long-term application performance. At low concentrations (10 mg kg⁻¹), NanoCu pesticides significantly affected the diversity of soil microorganisms. Notably, K60 decreased the negative influence on microorganism diversity compared with the original commercial pesticides, and improved alpha diversity and microbial species composition variation. Besides, K60 enhanced the phosphorus deficiency resistance of lettuces via the adjustment of microelement homeostasis. In particular, 5 μM K60 increased the Cu and P uptake in lettuce root by 77.81% and 76.12%, and increased the Mg and K uptake in root by 44.95% and 39.74%. The nanopesticide dosage exhibited more influence than the nanocarrier size on lettuce root ionome variation. Our research findings emphasize the implementation of sustainable strategies to enhance the utilization efficiency of commercial pesticides while mitigating ecological risks. These insights are expected to significantly contribute to the development of valuable concepts and serve as key references for the future market introduction of additional nanopesticides.