Relationships between kiwifruit bacterial canker disease and kiwifruit productivity

Abstract

Bacterial canker disease caused by a virulent strain of Pseudomonas syringae pv actinidiae (PsaV) has affected kiwifruit vines in New Zealand since 2010 This study investigated the association of PsaV with productivity within Hayward and Hort16A varieties PsaV infection status and date of diagnosis for 3309 infected orchards were provided by Kiwifruit Vine Health while Zespri provided productivity data Linear regression models were constructed to determine the relationship between production and PsaV infection in Hayward and Hort16A orchards Results showed a significant relationship between the numbers of weeks PsaV was detected in Hort16A orchards and a reduction in productivity This was likely due to the removal of Hort16A vines or productive areas of canopy in response to the presence of severe symptoms within an orchard A similar significant relationship was also found in Hayward orchards although the reduction in productivity was smaller and took longer to develop than in Hort16A