A non-phytotoxic fungicidal composition comprising an alkali or ammonium salt of a high MW organic fatty acid forming an emulsion, and tea tree essential oil, terpinen-4-ol oil solubilized in the emulsion, and a method of producing the aforesaid non-phytotoxic biocide, including the steps of admixing alkali or ammonium salts with organic fatty acids so an emulsion is obtained, and admixing terpinen-4-ol oil in the emulsion until full solubilization is obtained.