Briefly described, embodiments of this disclosure, among others, include compositions, gels, methods for synthesizing multifunctional silica based nanoparticle gel, method of treating, preventing, or both treating and preventing, a disease in a plant species, method for simultaneously treating citrus plants for citrus canker and preventing the invasion of an Asian Citrus Psyllid (ACP) vector that carries the pathogen and spreads the citrus greening disease in citrus plants, and the like.