Method for treatment and control of plant disease

A method of preventing or reducing symptoms or disease associated with Xylella fastidiosa or Xanthomonas in a plant, comprising contacting said plant with particles of at least one virulent bacteriophage for Xylella fastidiosa and/or Xanthomonas, wherein the virulent bacteriophage is selected from the group consisting of the Xfas100 phage type, the Xfas300 phage type and Xfas500 phage type;

• wherein the Xfas100 phage type has the following characteristics:
• (a) the bacteriophage is capable of lysing said Xylella fastidiosa and/or Xanthomonas bacteria;
• (b) the bacteriophage infects a cell by binding to a Type IV pilus;
• (c) the bacteriophage comprises a non-contractile tail and a capsid size ranging from 55-77 nm in diameter, with a morphology typical of Siphoviridae family;
• and
• (d) the genomic size of the bacteriophage is about 55,500 bp to 56,200 bp;
• the Xfas300 phage type has the following characteristics:
• (e) the bacteriophage is capable of lysing said Xylella fastidiosa and/or Xanthomonas bacteria;
• (f) the bacteriophage infects a cell by binding to a Type IV pilus;
• (g) the bacteriophage comprises a morphology typical of Podoviridae family characterized by a non-contractile tail with a capsid size ranging from 58-68 nm in diameter;
• and
• (h) the genomic size of the bacteriophage is about 43,300 bp to 44,600 bp;
• or the Xfas500 phage type has the following characteristics:
• (i) the bacteriophage is capable of lysing said Xylella fastidiosa and/or Xanthomonas bacteria;
• (j) the bacteriophage infects a cell by adsorption to a Type IV pilus;
• (k) the bacteriophage comprises a contractile tail with a capsid size ranging from 85 nm-95 nm in diameter;
• and
• l) the genomic size of the bacteriophage is about 190,000 bp to 230,000 bp.