A novel approach to control Botrytis cinerea fungal infections: uptake and biological activity of antifungals encapsulated in nanoparticle based vectors

Botrytis cinerea, responsible for grey mold diseases, is a pathogen with a broad host range, affecting many important agricultural crops, in pre and post harvesting of fruits and vegetables. Commercial fungicides used to control this pathogen are often subjected to photolysis, volatilization, degradation, leaching, and runoff during application. In this context, the use of a delivery system, based on poly (lactic-co-glycolic acid) nanoparticles (PLGA NPs) represents an innovative approach to develop new pesticide formulations to successfully fight B. cinerea infections. In order to study NPs uptake, B. cinerea conidia and mycelium were treated with PLGA NPs loaded with the high fluorescent probe coumarin 6 (Cu6-PLGA NPs) and analyzed under ApoTome fluorescence microscopy. The observations revealed that 50 nm Cu6-PLGA NPs penetrated into B. cinerea conidia and hyphae, as early as 10 min after administration. Pterostilbene, a natural compound, and fluopyram, a synthetic antifungal, were entrapped in PLGA NPs, added to B. cinerea conidia and mycelium, and their antifungal activity was tested. The results revealed that the compounds loaded in NPs exhibited a higher activity against B. cinerea. These results lay the foundations for the use of PLGA NPs as a new strategy in plant pest management.