Xanthomonas colonies are yellow, slightly mucoid,
raised and circular. Use of Tween causes a clear halo to
form around the yellow colony in 3–7 days. For further
purification, individual yellow-pigmented colonies are
recovered after re-streaking on nutrient agar on a non-selective
medium. Identification tests of putative Xanthomonas
Spp. should then be carried out