Rate and Timing of Application of Biostimulant Substances to Enhance Fruit Tree Tolerance toward Environmental Stresses and Fruit Quality

Biostimulants represent an important category of agricultural inputs characterized by multiple functions. They are used to assist crop growth, yield and enhance the final quality produces. Their classification is generally based on claims (i.e., which services they provide crop), even though their biological effects often species-dependent highly influenced external factors growing conditions). This review provides a survey available scientific literature use biostimulant substances in fruit production, with specific aim clarify predominant mode time application. An extremely varied scenario emerged where foliar treatments common for seaweed extracts, humic fulvic acids, protein hydrolysates silicon applied both soil (drench) or sprayed canopy. Dosages were difficult compare between considered studies given wide range tested products uncertainty actual composition. Regarding number applications, biostimulants following calendar-approach, covering most season. When intended tolerance toward environmental stresses, mainly before stressful event prime plant physiological defenses. Further multiple-year research projects standard methodological protocols urgently needed verify clear compliance evaluate cost-effectiveness production sector.