Bacteriophages a potential biocontrol agent against walnut blight (<i>Xanthomonas campestris</i> pv juglandis)

Abstract

During autumn 2000 isolates of bacteria were collected from blighted nuts leaves buds and petioles of walnut trees from all over New Zealand From among these isolates Xanthomonas campestris pv juglandis lines were identified by a range of cultural DNA fingerprinting and morphological tests Concurrently bacteriophages which attack X campestris pv juglandis were isolated from the soils under the same trees Phages were readily isolated from a depth of 25 cm In the following spring phages were also isolated from the canopy of trees grown at Lincoln Phage typing was carried out to produce a set of phages capable of destroying all bacterial isolates A subset of the isolated phages was characterized Several phages isolated from the soil were identified under the electron microscope as being from the 955; phage group with long unsheathed tails and hexagonal heads Phages isolated from the canopy belonged to several other groups of phages Short term storage had little effect on canopy phage survivability Differences in hardiness were found between the phages The search to locate effective hardy phages for use as biobactericides continues