A method for controlling pathogens on a plant tissue of a growing plant having roots and leaves, said method comprising treating said growing plant with an aqueous solution resulting from the dissolution in water of a powdered composition comprising a dry, water soluble mixture of: (i)-a) 30-60% w/w of a solid hydrogen peroxide precursor which is sodium perborate, sodium percarbonate, ammonium percarbonate, sodium peroxyhydrate, calcium peroxide, sodium peroxide, sodium perborate monohydrate, sodium perborate tetrahydrate, sodium persulfate, potassium monopersulfate, perphosphate, magnesium peroxide, zinc peroxide, urea hydrogen peroxide, perhydrate of urea, thiourea dioxide, or mixtures thereof, (i)-b) 10-40% w/w a pH adjusting agent which is sulfuric acid, citric acid, phosphoric acid, nitric acid, hydrochloric acid, glycolic acid, formic acid, acetic acid, hydrofluoric acid, nitrous acid, hydrocyanic acid, benzoic acid, carboxylic acid, lactic acid, acetic acid, oxalic acid, sulfamic acid, phosphorous acid, dipicolinic acid, urea&bullHCl, boric acid, or mixtures thereof, (i)-c)10-40% w/w of an acetylating agent which is selected from the group consisting of a N-acyl compound or a O-acyl compound containing a radical CH3-CO- and (ii)1-30% w/w of a SAR inducer which is a water soluble silicate salt defining a source of silicate ions and selected from the group consisting of potassium silicate, sodium silicate, sodium metasilicate, or a mixture thereof wherein said composition generates in situ peracetic acid (PAA) upon addition of water wherein (i)-a), (i)-b) and (i)-c) represent a peracetic acid precursor and wherein when 2 g of said dry, water soluble mixture of (i)-a), (i)-b), (i)-c) and (ii) is admixed with 1000 g of water, about 100 to 250 ppm of 30 peracetic acid (PAA) are generated in situ at pH 7.0 + 2, and wherein the resulting aqueous solution comprises peracetic acid at a concentration and a pH which are not harmful for said plant tissue and the SAR indu
