Site-specific pesticide delivery is one of the potential strategies to enhance the use of fungicides and decrease undesirable environmental damages. Herein, a β-glucanase enzyme-responsive nanovehicle used for controlling chlorothalonil (CHT) release in the plant vascular system was synthesized (CHT@MSNs-β-glucans) by attaching β-glucans extracted from the yeast cell wall on MSNs pore rims for the management of rice blast (Magnaporthe grisea). CHT@MSNs-β-glucans characteristics were examined by transmission electron microscopy (TEM), scanning electron microscopy (SEM), Fourier transfer infrared (FT-IR) spectroscopy, thermogravimetric analysis (TGA), N 2 isotherm, and Zetasizer. The obtained results showed that CHT@MSNs-β-glucans have excellent enzymatic release dependency, an outstanding loading efficacy of 24.99%, remarkable protection from acidic and alkaline conditions, and UV shielding ability up to 3 times greater than that of CHT commercial product (CHT-WP). CHT@MSNs-β-glucans showed excellent bioactivity against rice blast compared with CHT-WP. Moreover, CHT@ MSNs-β-glucans showed better distribution in different tissues of rice plants. Additionally, CHT@MSNs-β-glucans showed 2.6 times lower toxicity to Daphnia magna and exhibited lower changes in soil microbial abundance than CHT-WP. This study provides significant sustainable management of plant pathogens for better farming.

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Interactive release formulations are one of the best strategies for enhancing pesticides usage. A 112 nm α-amylase enzyme-responsive nanosystem loaded with abamectin (ABM) was synthesized by attaching carboxymethyl starch (CMS) to the surface of hollow mesoporous silica (HMS) to improve ABM insecticidal activity and photostability. ABM-loaded HMS–CMS characteristics were tested. ABM release behavior under different pH levels and in the presence or absence of α-amylase enzyme was investigated. The ultraviolet (UV) protection ability and the insecticidal activity against one of the model insects, Spodoptera littoralis, were examined. The adhesion properties of ABM-loaded HMS–CMS on corn leaves have been tested. The prepared ABM-loaded HMS–CMS presented a high loading efficacy of up to 24.77% and enzymatic release dependency of up to 88.34% after 17 days of adding α-amylase enzyme. After 60 h of UV radiation, only 17.7% of the loaded ABM into HMS–CMS has deteriorated. ABM-loaded HMS–CMS showed better insecticidal activity against S. littoralis than abamectin commercial formulation (ABM-EC). After 14 days, the LC50 of ABM-loaded HMS–CMS was 51.7% lower than that of ABM-EC. The prepared ABM-loaded HMS–CMS showed excellent adhesion on corn leaves. We recommend using such formulations to achieve better and sustainable farming.

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In this work, an enzyme-responsive nanovehicle for improving captan (CAP) contact fungicide bioactivity and translocation in plant tissues was synthesized (CAP-MSNs-β-glucan) by attaching β-glucan to the outer surface of mesoporous silica nanoparticles. CAP-MSNs-β-glucan properties were tested by FTIR, ζ-potential, DLS, XRD, TGA, FE-SEM, and HR-TEM. Cargo protection ability of CAP-MSNs-β-glucan from photolysis and hydrolysis was examined in comparison to CAP commercial formulation (CAP-CF). CAP-MSNs-β-glucan distribution in plant tissues, bioactivity against Fusarium graminearum , and biotoxicity toward zebrafish ( Danio rerio ) were tested and compared with that of CAP-CF. CAP-MSNs-β-glucan results showed good loading efficacy reaching 18.39% and enzymatic-release dependency up to 83.8% of the total cargo after 20 days of β-glucan unsealing. CAP-MSNs-β-glucan showed significant release protection under pH changes. MSNs-β-glucan showed excellent CAP protection from UV. CAP-MSNs-β-glucan showed better distribution in corn tissues and 1.28 more inhibiting potency to Fusarium graminearum than CAP-CF. CAP-MSNs-β-glucan showed 1.88 times lower toxicity than CAP-CF to zebrafish after 96 h of treatment. We recommend using such formulations to overcome shortcomings of contact fungicides and achieve better and sustainable farming.

BACKGROUND: Downy mildew, a devastating disease of cucurbitaceous crops caused by Pseudoperonospora cubensis. Although a variety of fungicides are used to control downy mildew, choosing an effective product can be challenging. Environmental stimulus-responsive pesticide delivery systems have great potential to improve the effectiveness of disease and pest control and reduce the impact on environmentally beneficial organisms. RESULTS: In this work, a disulfide bond (SS)-modified and chitosan oligosaccharide (COS)-capped hollow mesoporous silica (HMS) pesticide delivery system was synthesized using a hard template method for the control of downy mildew in cucurbit crops. The synthesized nanoparticles were loaded with dimethomorph (DMM)