Using a simple one-pot method, we developed a prochloraz (Pro) and pH-jump reagent-loaded zeolitic imidazolate framework-8 (PD@ZIF-8) composite for the smart control of Sclerotinia disease. The pH-jump reagent can induce the acidic degradation of ZIF-8 using UV light to realize the controlled release of Pro. Thus, the physical properties of PD@ZIF-8, such as its release, formulation stability, and adhesion, were investigated in detail. The results showed that the quantity of Pro released by PD@ZIF-8 under UV light irradiation (365 nm) was 63.4 ± 3.5%, whereas under dark conditions, it was only 13.7 ± 0.8%. In vitro activity indicated that the EC50 of PD@ZIF-8 under UV light irradiation was 0.122 ± 0.02 μg/mL, which was not significantly different from that of Pro (0.107 ± 0.01 μg/mL). Pot experiments showed that the efficacy of PD@ZIF-8 under light irradiation was 51.2 ± 5.7% for a fungal infection at 14 days post-spraying, whereas the effectiveness of prochloraz emulsion in water was only 9.3 ± 3.3%. Furthermore, fluorescence tracking of ZIF-8 and biosafety experiments showed that ZIF-8 could be absorbed by plant leaves and transported to various parts of oilseed rape in a short period of time and that PD@ZIF-8 was relatively safe for plants and HepG2 cells. These results highlight the potential of the composite to provide efficient and smart delivery of fungicides into plants for protection against diseases and provide an idea for developing sustainable agriculture.

Developing an effective and safe technology to control severe bacterial diseases in agriculture has attracted significant attention. Here, ZnO nanosphere and ZIF-8 are employed as core and shell, respectively, and then a pH-responsive core–shell nanocarrier (ZnO-Z) was prepared by in situ crystal growth strategy. The bactericide berberine (Ber) was further loaded to form Ber-loaded ZnO-Z (Ber@ZnO-Z) for control of tomato bacterial wilt disease. Results demonstrated that Ber@ZnO-Z could release Ber rapidly in an acidic environment, which corresponded to the pH of the soil where the tomato bacterial wilt disease often outbreak. In vitro experiments showed that the antibacterial activity of Ber@ZnO-Z was about 4.5 times and 1.8 times higher than that of Ber and ZnO-Z, respectively. It was because Ber@ZnO-Z could induce ROS generation, resulting in DNA damage, cytoplasm leakage, and membrane permeability changes so the released Ber without penetrability more easily penetrated the bacteria to achieve an efficient synergistic bactericidal effect with ZnO-Z carriers after combining with DNA. Pot experiments also showed that Ber@ZnO-Z significantly reduced disease severity with a wilt index of 45.8% on day 14 after inoculation, compared to 94.4% for the commercial berberine aqueous solution. More importantly, ZnO-Z carriers did not accumulate in aboveground parts of plants and did not affect plant growth in a short period. This work provides guidance for the effective control of soil-borne bacterial diseases and the development of sustainable agriculture.

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Soil-borne diseases have caused substantial economic losses to agricultural production due to their rapid onset and few means of control. Here, pyraclostrobin (Pyr) microcapsules (Pyr@MCC) with temperature-responsive pesticide release capability were prepared using temperature-sensitive phase-change materials as capsule cores. Then, the Pyr@MCC was organically combined with poly­(vinyl alcohol)-starch film (PVA/ST) to prepare a composite mulch film (PM/PVA/ST) with intelligent control of pesticide release rate according to external temperature change, which realized sustainable and efficient control of Phytophthora root rot (PRR) on soybean. Tensile tests showed that the PM/PVA/ST film exhibited good tensile deformation ability (134.9%) and high tensile stress (18.0 Mpa). The water vapor transmission rate test showed that the PM/PVA/ST film exhibited good barrier performance to H2O, CO2, and O2. The release test data proved that the PM/PVA/ST film could slowly release Pyr at lower temperatures (15 °C) and release Pyr rapidly at higher temperatures (35 °C), corresponding to the high temperature at which the Phytophthora root rot outbreak. In vitro antifungal and pot experiments showed that the PM/PVA/ST film had a good control efficiency on Fusarium spp. These results show that the functional pesticide microcapsules loaded onto the film have good application potential for controlling PRR on soybean. In general, this composite mulch film provided some innovative research ideas for optimizing the pesticide delivery pathway and thereby efficiently controlling soil-borne pests and diseases, reducing the frequency and amount of pesticide use and minimizing white pollution from traditional plastic mulch films.

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