A method of suppressing mold, heating, and spoilage in harvested forage products, the method comprising: cutting forage from plants growing in an agricultural field, the forage having a negatively-charged forage surface; and after said cutting of the forage, coating the negatively-charged forage surface with a layer of treatment composition consisting only of: a mold-suppression active ingredient that is polydimethylsiloxane (PDMS) that is non-water-soluble and of the formula R3-SiO[Si 2O]nSi-R3 where R is any organic or inorganic functional group and n is any number, of 2 or more, of repeating monomer units; and multiple components selected from the group consisting only of: water; carrier liquids; emulsifiers; fermentation products; preservatives; and components for keeping the PDMS suspended or mixed in the treatment composition, said preservatives being selected from the group consisting only of carbonates, phosphates, mineral carbonate, cobalt carbonate, zinc carbonate, potassium carbonate, sodium carbonate, phosphoric acid, acetic acid, lactic acid, proprionic acid, and sulfuric acid; wherein said treatment spray is coated on the forage in an amount equal to 18 - 300 weight-ppm PDMS on said forage, dry matter basis. cutting forage from plants growing in an agricultural field, the forage having a negatively-charged forage surface; and after said cutting of the forage, coating the negatively-charged forage surface with a layer of treatment composition consisting only of: a mold-suppression active ingredient that is polydimethylsiloxane (PDMS) that is non-water-soluble and of the formula R3-SiO[Si 2O]nSi-R3 where R is any organic or inorganic functional group and n is any number, of 2 or more, of repeating monomer units; and multiple components selected from the group consisting only of: water; carrier liquids; emulsifiers; fermentation products; preservatives; and components for keeping the PDMS suspended or mixed in the treatment composition, said preservatives being selected from the group consisting only of carbonates, phosphates, mineral carbonate, cobalt carbonate, zinc carbonate, potassium carbonate, sodium carbonate, phosphoric acid, acetic acid, lactic acid, proprionic acid, and sulfuric acid; a mold-suppression active ingredient that is polydimethylsiloxane (PDMS) that is non-water-soluble and of the formula R3-SiO[Si 2O]nSi-R3 where R is any organic or inorganic functional group and n is any number, of 2 or more, of repeating monomer units; and multiple components selected from the group consisting only of: water; carrier liquids; emulsifiers; fermentation products; preservatives; and components for keeping the PDMS suspended or mixed in the treatment composition, said preservatives being selected from the group consisting only of carbonates, phosphates, mineral carbonate, cobalt carbonate, zinc carbonate, potassium carbonate, sodium carbonate, phosphoric acid, acetic acid, lactic acid, proprionic acid, and sulfuric acid; water; carrier liquids; emulsifiers; fermentation products; preservatives; and components for keeping the PDMS suspended or mixed in the treatment composition, said preservatives being selected from the group consisting only of carbonates, phosphates, mineral carbonate, cobalt carbonate, zinc carbonate, potassium carbonate, sodium carbonate, phosphoric acid, acetic acid, lactic acid, proprionic acid, and sulfuric acid; wherein said treatment spray is coated on the forage in an amount equal to 18 - 300 weight-ppm PDMS on said forage, dry matter basis.