A team led by Prof. WU Zhengyan and ZHANG Jia from the Hefei Institutes of Physical Science of Chinese Academy of Sciences, developed a new, eco-friendly way to deliver pesticides using porous microspheres made from halloysite nanotubes (HNTs). These microspheres are created through reversible metal-ligand coordination interaction, which makes them responsive to changes in pH, humidity, and enzymes.
The results were published in small.
Traditional pesticide formulations are limited by their rapid release, resulting in low efficiency and serious environmental risks. To address this, researchers are developing greener pesticides with controlled-release properties. Improving the release of existing active ingredients is a simpler and more effective way to enhance efficiency and reduce ecological risks, mitigating misuse.
In this research, the team loaded the insecticide avermectin (AVM) and the herbicide prometryn (PMT) into the HNT microspheres. They then coated the microspheres with a tannic acid/iron complex, fabricating two controlled-release pesticides named HCEAT and HCEPT. These new formulations have high pesticide loading capacities and effectively release the pesticides in response to weak acids.
Additionally, these pesticides show better resistance to ultraviolet light, better foliar adhesion, and reduced leaching into the soil, with no observed adverse effects on plants and soil organisms.
"This approach could lead to more efficient and environmentally friendly pesticide use in agriculture, supporting sustainable farming practices," said TENG Guopeng, first author of the paper.
Schematic illustration of fabrication and mechanism of smart pesticides. (Image by TENG Guopeng)