Using Coordination Assembly as the Microencapsulation Strategy to Promote the Efficacy and Environmental Safety of Pyraclostrobin

The broad-spectrum and widely used fungicide pyraclostrobin is encapsulated using a coordination assembly between Fe3+ and tannic acid to promote its efficacy and environmental safety. The deposition is confirmed by the surface zeta potential and energy dispersive spectroscopy. Optical microscopy, scanning electron microscopy, transmission electron microscopy (TEM), and atomic force microscopy (AFM) observations are integrated to characterize the pyraclostrobin-loaded microcapsules (MCs). These MCs retain a spherical shape when suspended in water but quickly deform or rupture after the water evaporates when deposited for 1 cycle. After sequential deposition of the membrane, the membrane thickness increases linearly according to TEM and AFM height analyses. These MCs show satisfactory efficacy on rice blast, resulting in significantly higher yields at doses of 120 and 180 g ha(-1). Moreover, these MCs display significantly lower toxicity to Brachydanio rerio, Daphnia magna, Xenopus laevis, and Rana nigromaculata. Overall, this novel microencapsulation strategy is capable of promoting the efficacy and environmental safety of pyraclostrobin.