Using qPCR to monitor populations of <i>Pseudomonas syringae</i> pv <i>actinidiae</i> on kiwifruit vines

Abstract

Populations of Pseudomonas syringae pv actinidiae (Psa) on vines sprayed with a biological control agent (Bacstar; Bacillus amyloliquefaciens D747; Ba) and on untreated control vines were monitored using qPCR Leaf discs were taken from vines in February 2014 3 months after the final of three spray applications of Bacstar in October and November 2013 An aliquot of leaf washings in bacterial saline (BS) was spread on to potato dextrose agar in Petri plates and the numbers of colonies of Ba were counted DNA was extracted from the remaining BS and the quantity of Psa DNA was determined using qPCR Ba was recovered from leaf discs that had been sprayed with Bacstartrade; in greater numbers than from unsprayed leaf discs (P<005) Psa was recovered in greater numbers from the