The broad-spectrum and widely used fungicide pyraclostrobin is encapsulated using a coordination assembly between Fe 3+ 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.

The application of pesticide microcapsules (MCs) in agriculture is becoming more and more popular. In this study, the effects of different wall materials on the stomach toxicity, contact toxicity, length of efficacy, and photolysis characteristics of pesticide microcapsules were investigated. The results showed that microencapsulation reduced the stomach and contact toxicities of phoxim and prolonged the efficacy of this light-sensitive chemical in the greenhouse test. Neither of the degradation curves for microencapsulated phoxim under ultraviolet light fit a first-order model, although the emulsifiable concentrate (EC) degradation curve fit it well. The phoxim-loaded polyurea microcapsules (PUA-MCs) showed significantly increased UV-resistance ability, stomach toxicity, and contact toxicity compared with the phoxim-loaded urea-formaldehyde microcapsules (UF-MCs). These experiments indicated that it is crucial to select the appropriate wall materials for pesticide microcapsules on the basis of application sites and physicochemical properties of pesticide active ingredients.

A response surface methodology with four factors at five levels was adopted to optimize a model thiacloprid suspension concentrate.

A model chlorpyrifos microcapsule was prepared using coordination assembly between Fe 31 and tannic acid (TA). The influence of independent variables such as the dropping rate of TA (X 1 ) and Fe 31 (X 3 ), the concentration of TA (X 2 ) and Fe 31 (X 4 ), and the reaction temperature (X 5 ) on the encapsulation efficiency (R 1 ) and release characteristics (R 2 ) of the microcapsule had been investigated, based on a central composite design with five factors and five levels. The results showed that the main factors influencing R 1 and R 2 were X 4 and X 2 , then the interaction between X 2 and X 4 , followed by X 5 and X 3 . The optimal formula mainly based on higher R 1 and lower R 2 were determined and then tested. The optimized conditions led to an encapsulation efficiency and cumulative release proportion of 97.12% 6 0.72% and 40.07% 6 0.53%, along with the average relative errors of predicted values being 1.78% and 21.60%, respectively.

A model 25% suspension concentrate (SC) of thiacloprid was adopted to evaluate an integrative approach of uniform design and response surface methodology. Tersperse2700, PE1601, xanthan gum and veegum were the four experimental factors, and the aqueous separation ratio and viscosity were the two dependent variables. Linear and quadratic polynomial models of stepwise regression and partial least squares were adopted to test the fit of the experimental data. Verification tests revealed satisfactory agreement between the experimental and predicted data. The measured values for the aqueous separation ratio and viscosity were 3.45% and 278.8 mPa·s, respectively, and the relative errors of the predicted values were 9.57% and 2.65%, respectively (prepared under the proposed conditions). Comprehensive benefits could also be obtained by appropriately adjusting the amount of certain adjuvants based on practical requirements. Integrating uniform design and response surface methodology is an effective strategy for optimizing SC formulas.