Editorial: Kiwifruit crisis highlights need for vigilance

File photo / APN

Since the boom times of the 1980s, the kiwifruit industry has settled down to become a stable and somewhat under-appreciated export earner.

There have been none of the traumas associated with, say, mad cow disease scares in the livestock industry or fire blight elsewhere in the horticultural sector. Until now, that is.

The discovery of the Pseudomonas syringae pv actinidae (Psa) bacterium has offered a sharp reminder of the importance of a $1.4 billion industry and, more fundamentally, this country's reliance on strict biosecurity controls.

We still do not know the full extent and severity of the damage, or how and when the bacterium found its way here. It seems increasingly likely, however, that it could have been present for many years and causing so little damage that it passed unnoticed.

Alternatively, it could be a recent arrival that cannot be contained and has the potential to become a sizeable problem.

What we do know is that Psa, which was first identified in Japan 25 years ago, caused widespread damage to Italy's kiwifruit crop in 1992 and was a problem in that country again last year.

It can have a devastating impact on kiwifruit vines, even if it does not affect the fruit or pose any risk to human health.

In a worst-case scenario, this infestation has considerable implications for the health of this country's vines, crop productivity and market access. The response, therefore, has had to be as wide-ranging as it is well-rehearsed. First, export markets needed reassurance.

This appears to have been successful. Australia and the United States have banned imports of New Zealand nursery stock but have shown no inclination to extend this to fruit. That could yet change, so it is important a clear picture of the infestation is provided as soon as possible.

Tackling the problem will hinge on the judgment of biosecurity officials. In particular, they must consider the geographical spread of Psa and the aggressiveness of the strain. It seems on the cards that the infestation is not confined to an area around Te Puke.

This suggests eradication, a process that would involve cutting and burning the infected vines or deep burial, will be an impossibility. If so, the bacterium will have to be managed by orchardists.

The spread of Psa may support the theory that it has been here for some time and is relatively benign. Even that poses problems, however. New Zealand prides itself as the source of disease-free products.

There remains the threat of a backlash from overseas buyers, which would affect the Bay of Plenty, in particular. It derives 20 per cent of its gross domestic product from the kiwifruit industry. Yet even that threat should be able to be contained. Psa is already present in Asia and Europe.

An import ban on our kiwifruit in those regions seems unlikely. This is especially reassuring in the case of Japan, which has a well-documented fear of imported food.

New Zealand has created quarantine standards that are second to none in recognition of its image and dependence on agricultural exports. Clearly, they were not sufficient in this instance.

It is virtually inevitable, however, that there will be breaches. Even so, this issue for a relatively trouble-free industry reinforces the fact that this country has good reason to be more vigilant than any other.