New Zealand’s fight against kiwifruit canker has entered a new stage with the discovery of two separate strains of the bacterial disease.
Of the 126 orchards currently testing positive for Pseudomonas syringae pv actinidiae (Psa), at least 25 are reportedly infected by the Italian strain of the disease, which wreaked havoc on that country’s kiwifruit industry last year.
Orchards infected with the ‘Italian isolate’ are concentrated east of Te Puke in the Bay of Plenty, the site of the original Psa detection in November last year.
Infected orchards from the region last year reported symptoms including the weeping of red sap, while symptoms from other areas were limited to leaf spotting.
The remainder of positive detections outside Te Puke appear to be the less virulent Asian strain, which has been successfully managed by kiwifruit growers in South Korea and Japan for many years.
The new discovery may mean New Zealand’s kiwifruit industry takes a more aggressive approach to management of the disease, with an increase in vine removal in orchards affected by the Italian Psa strain.
John Burke, general manager of Kiwifruit Vine Health (KVH), the body tasked with management of the disease, told local media it may be possible to confine the strain to the Te Puke area with vine removal and copper-based sprays.
About 15ha of infected orchards have been removed already, and Mr Burke said that figure is likely to increase. KVH will buy the current crop from affected growers and provide financial assistance as part of the NZ$40m Psa management plan.
