The nanoencapsulation of pesticides in biodegradable polymers confers several advantages to conventional agrochemicals, such as protection against losses due volatilization and degradation of the active ingredient, as well as the augment of water dispersion, allowing for their application on crops without requiring the use of organic solvents that could harm the user and the environment. This characteristics could enhance the productivity, reducing both costs and environmental pollution. In this work the propiconazole fungicide, forming part of a commercial formulation as well as in its pure state, was encapsulated using as carriers the biodegradable polymer poly lactic acid (PLA) and the biodegradable co-polymer poly (lactic-co-glicolic) acid, all with the aim of generate controlled fungicide release systems to augment the efficiency of the treatments of the Fusarium dieback disease. The most efficient system obtained presented nanospheres of 146.28 nm and an encapsulation efficiency over 42%. The antifungal activity tests showed that the use of this nanoencapsulated fungicide system enhances the growth inhibition percentage in 5%, obtaining a formulation that presents good dispersion in water without the need of organic emulsifier agents.

Xyleborus sp beetles are types of ambrosia beetles invasive to the United States and recently also to Mexico. The beetle can carry a fungus responsible for the Laurel Wilt, a vascular lethal disease that can host over 300 tree species, including redbay and avocado. This problem has a great economic and environmental impact. Indeed, synthetic chemists have recently attempted to develop new neonicotinoids. This is also due to severe drug resistance to “classic” insecticides. In this research, a series of neonicotinoids analogs were synthesized, characterized, and evaluated against Xyleborus sp. Most of the target compounds showed good to excellent insecticidal activity. Generally, the cyclic compounds also showed better activity in comparison with open-chain compounds. Compounds R-13, 23, S-29, and 43 showed a mortality percent of up to 73% after 12 h of exposure. These results highlight the enantioenriched compounds with absolute R configuration. The docking results correlated with experimental data which showed both cation-π interactions in relation to the aromatic ring and hydrogen bonds between the search cavity 3C79 and the novel molecules. The results suggest that these sorts of interactions are responsible for high insecticidal activity.

Synthetic fungicides are used to control fungal diseases in plants, such as those caused by members of the Fusarium genus. Nonetheless, the over-application of synthetic formulations can generate other problems, like phytotoxicity, or the pollution of water and soil. In this context, botanical extracts with antifungal properties can represent an environmentally friendly alternative to control fungal infections. The application of natural products in the form of crude extracts still requires the incorporation of toxic organic solvents to be used as vehicle. Nanotechnology allows the dispersion of hydroalcoholic extracts in water simply by the nanoencapsulation of the active molecules in a biodegradable polymer, with the advantage that no organic solvents are required while, at the same time, this polymer may protect the extract against photodegradation. The present study aims to encapsulate an antifungal Piper schlechtendalii crude extract in poly(lactide-co-glycolide) acid nanospheres, conferring good dispersion in water while protecting the active ingredients against degradation by solar irradiation. The particle size, zeta potential, and encapsulation efficiency obtained were 170 nm, -37 mV, and 33.7 %, respectively. The system obtained showed good dispersion in water, in the form of a colloidal suspension of polymeric nanospheres. After 24 h of exposure to UV-A radiation, crude extract only retained 58.35 % of its original Fusarium solani growth inhibition capacity, while the nanoencapsulated extract retained 70 %. The study concluded that the biodegradable polymer does confer photoprotection to the active ingredients in the antifungal Piper extract while simultaneously removing the necessity of organic solvents as vehicles, potentially reducing the environmental impact. Resumen. Los fungicidas sintéticos son usados para controlar enfermedades fúngicas en plantas, como aquellas causadas por el género Fusarium. Sin embargo, la aplicación desmedida de formulaciones sintéticas puede generar otros problemas, como fitotoxicidad, o contaminación de agua y suelos. En este contexto, extractos botánicos con propiedades antifúngicas representan una alternativa ecológicamente amigable para controlar infecciones fúngicas. La aplicación de productos naturales en forma de extractos crudos aún requiere la incorporación de disolventes orgánicos tóxicos para ser utilizados como vehículos. La nanotecnología permite la dispersión de extractos hidroalcóholicos en agua simplemente nanoencapsulando las moléculas activas en polímeros biodegradables, con la ventaja de que no requiere disolventes orgánicos mientras que, a la vez, dicho polímero protege al extracto contra fotodegradación. El presente estudio busca encapsular un extracto crudo antifúngico de Piper schlechtendalii en nanoesferas de poli(ácido láctico-co-glicólico), brindando buena dispersión en agua mientras se protege a los ingredientes activos contra degradación por luz solar. El tamaño de partícula, potencial zeta, y eficiencia de encapsulación obtenidos fueron 170 nm, -37 mV, y 33.7 %, respectivamente. El sistema obtenido mostró buena dispersión en agua, en forma de una suspensión coloidal de nanoesferas poliméricas. Después de 24 h de exposición a radiación UV-A, el extracto crudo solo retuvo 58.35 % de su inhibición de crecimiento de Fusarium solani original mientras que el extracto nanoencapsulado retuvo el 70 %. El estudio concluyó que el polímero biodegradable logra brindar fotoprotección a los ingredientes activos del extracto de Piper mientras que, simultáneamente, remueve la necesidad de usar disolventes orgánicos como vehículo, reduciendo potencialmente el impacto ambiental.