Efficiency of Artemisia annua L. essential oil and its chitosan/tripolyphosphate or zeolite encapsulated form in controlling Sitophilus oryzae L

Chitosan-based insecticide formulations for insect pest control management: A review of current trends and challenges

Future agricultural practices necessitate green alternatives to replace hazardous insecticides while distinguishing between pests and beneficial insects. Chitosan, as a biological macromolecule derived from chitin, is biodegradable and exhibits low toxicity to non-target organisms, making it a sustainable alternative to synthetic pesticides. This review identifies chitosan-derivatives for insecticidal activity and highlights its efficacy including genotoxicity, defense mechanism, and disruption of insect's exoskeleton at different concentrations against several insect pests. Similarly, synergistic effects of chitosan in combination with natural extracts, essential oils, and plant-derived compounds, enhances insecticidal action against various pests was evaluated. The chitosan-based insecticide formulations (CHIF) in the form of emulsions, microcapsules, and nanoparticles showed efficient insecticide action on the targeted pests with less environmental impact. The current challenges associated with the field-trial application were also recognized, by optimizing potent CHIF-formulation parameters, scaling-up process, and regulatory hurdles addressed alongside potential solutions. These findings will provide insight into achieving the EU mission of reducing chemical pesticides by 50 %.

pH-responsive bentonite nanoclay carriers control the release of benzothiazolinone to restrain bacterial wilt disease

Ralstonia solanacearum (R. solanacearum) is one of the most devastating pathogens in terms of losses in agricultural production. Bentonite (Bent) is a promising synergistic agent used in development of effective and environmentally friendly pesticides against plant disease. However, the synergistic mechanism of Bent nanoclays with benzothiazolinone (BIT) against R. solanacearum is unknown. In this work, acid-functionalized porous Bent and cetyltrimethylammonium bromide (CTAB) were employed as the core nanoclays, and BIT was loaded into the clay to form BIT-loaded CT-Bent (BIT@CT-Bent) for the control of bacterial wilt disease. BIT@CT-Bent exhibited pH-responsive release behavior that fit the Fickian diffusion model, rapidly releasing BIT in an acidic environment (pH = 5.5). The antibacterial effect of BIT@CT-Bent was approximately 4 times greater than that of the commercial product BIT, and its biotoxicity was much lower than that of BIT under the same conditions. Interestingly, R. solanacearum attracted BIT@CT-Bent into the nanocomposites and induced cytoplasmic leakage and changes in membrane permeability, indicating an efficient and synergistic bactericidal effect that rapidly reduced bacterial density. In addition, BIT@CT-Bent significantly inhibited R. solanacearum biofilm formation and swimming activity, by suppressing the expression of phcA, solR and vsrC. Indeed, exogenous application of BIT@CT-Bent significantly suppressed the virulence of R. solanacearum on tobacco plants, with control effect of 75.48%, 72.08% and 66.08% at 9, 11 and 13 days after inoculation, respectively. This study highlights the potential of using BIT@CT-Bent as an effective, eco-friendly bactericide to control bacterial wilt diseases and for the development of sustainable crop protection strategies.