Systemic movement of Pseudomonas syringae pv. actinidiae in kiwifruit vines in New Zealand

Abstract

Systemic movement of Pseudomonas syringae pv. actinidiae (Psa) was investigated in inoculated potted kiwifruit vines in a greenhouse and in naturally infected mature vines in the orchard. In the potted vine experiment, trunks of 2-year-old Actinidia chinensis 'Hort16A' on the rootstock A. deliciosa 'Bruno' were wound-inoculated with Psa. After 151 days Psa was detected up to 95 cm from the point of inoculation. Psa moved upwards and downwards within the trunks, and through the scion and the rootstock, at similar rates. In the orchard experiments, samples were taken from mature kiwifruit vines at intervals along the vines during autumn, winter and spring. Psa moved systemically throughout mature 'Hort16A' and A. deliciosa 'Hayward' kiwifruit vines and was detected in symptomless tissues. In both greenhouse and field situations, Psa was not inhibited by the graft union and was able to move into the rootstock and down to the base of the vine.