Recently, there have been urgent economic and scientific demands to decrease the use
of chemical fungicides during the treatment of phytopathogens, due to their human health and
environmental impacts. This study explored the biocontrol efficacy of novel and eco-friendly preen
(uropygial) oil and endophytic Bacillus safensis in managing postharvest Botrytis grey mold in strawberry
fruit. The preen oil (25 L/mL) showed high antifungal activity against B. cinerea Str5 in
terms of the reduction in the fungal radial growth (41.3%) and the fungal colony-forming units
(28.6%) compared to the control. A new strain of Bacillus safensis B3 had a good potential to produce
chitinase enzymes (3.69 0.31 U/mL), hydrolytic lipase (10.65 0.51 U/mL), and protease enzymes
(13.28 0.65 U/mL), which are responsible for the hydrolysis of the B. cinerea Str5 cell wall and,
consequently, restrict fungal growth. The in vivo experiment on strawberry fruit showed that preen
(uropygial) oil reduced the disease severity by 87.25%, while the endophytic bacteria B. safensis B3
reduced it by 86.52%. This study reports the efficiency of individually applied bioagents in the control
of phytopathogenic fungi for the first time and, consequently, encourages their application as a new
and innovative strategy for prospective agricultural technology and food safety.