A pH‐ and redox‐stimulated responsive hollow mesoporous silica for triggered delivery of fungicides to control downy mildew of Luffa cylindrica

• Published in: Pest management science Vol. 78; no. 8; pp. 3365 - 3375
• Main Authors: Yang, Liupeng, Chen, Huiya, Yan, Wenjuan, Huang, Suqing, Cheng, Dongmei, Xu, HanHong, Zhang, Zhixiang
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01.08.2022; Wiley Subscription Services, Inc
• Subjects: Acute toxicity; Airborne microorganisms; Chemical pest control; Chitosan; chitosan oligosaccharide; Crops; Danio rerio; dimethomorph; Disease control; Downy mildew; Embryos; Environmental assessment; Environmental risk; Fungicides; Glutathione; Hatching; hollow mesoporous silica; Nanoparticles; Oligosaccharides; Pest control; Pesticides; pH effects; Risk assessment; Silica; Silicon dioxide; Survival; Synthesis; System effectiveness; Toxicity testing; Ultraviolet radiation; Zebrafish; zebrafish embryos; hollow mesoporous silica; chitosan oligosaccharide; zebrafish embryos; downy mildew; glutathione; dimethomorph
• ISSN: 1526-498X; 1526-4998
• DOI: 10.1002/ps.6964

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), denoted as DMM@HMS‐SS‐COS, and the developmental toxicity of these nanoparticles to zebrafish embryos were evaluated. The results showed that the prepared DMM@HMS‐SS‐COS exhibited excellent dual response properties to pH and glutathione (GSH), with an encapsulation rate of up to 24.36%. DMM@HMS‐SS‐COS has good ultraviolet (UV) radiation stability and adhesion properties. Compared with dimethomorph suspension concentrate (SC), DMM@HMS‐SS‐COS was more effective against downy mildew for up to 21 days. Toxicity tests showed that DMM@HMS‐SS‐COS significantly reduced the effect of DMM on the hatching rate and survival rate of zebrafish embryos. CONCLUSIONS This work not only demonstrates that DMM@HMS‐SS‐COS could be used as a nanodelivery system for intelligent control of downy mildew but also emphasizes the necessity of increasing the acute toxicity of nanoformulations to non‐target organisms in environmental risk assessment. © 2022 Society of Chemical Industry. The prepared nanoparticles had a glutathione (GSH)‐ and pH‐stimulated response for controlling the release of dimethomorph (DMM). Synthesized nanoparticles loaded with dimethomorph (DMM@HMS‐SS‐COS) were more effective and longer lasting than DMM suspension concentrate in controlling downy mildew.