Giuseppe Mannino
Over the last two decades, interest in plant biostimulants has expanded, driving scientific research, industrial initiatives, and regulatory efforts. European (EU) Regulation 2019/1009 defines them as products that stimulate plant nutritional processes regardless of nutrient content, enhancing efficiency, stress tolerance, product quality, or soil nutrient availability. Yet, ambiguities persist regarding their distinction from fertilizers and plant protection products, while effect assessment is hindered by agronomic variability and lack of standardized protocols. Scientific literature has largely focused on physiological interactions, highlighting impacts on growth, productivity, and stress resistance, but has often neglected broader systemic perspectives. This review adopts a multidimensional approach, analyzing: (i) the evolution of research, (ii) physiological roles and agronomic applications, (iii) market and industrial dynamics, and (iv) social perceptions. Through integrated bibliometric analysis, it offers a critical and comprehensive overview, moving beyond biology to explore the opportunities and challenges biostimulants present across agriculture, industry, and society.