Ian McLean Green candidate for Tauranga

'The War of the Worlds”. Tom Cruise saves his daughter from alien invaders that use human bodies to fuel their war machines. Neither Tom nor the military of the time were able to defend our planet, and the hero of the movie is the 'microbes” who attack and kill the invaders.

Vietnam, 1960's. The American invaders spray impossibly large amounts of 'defoliant” across an entire tropical landscape, coating their own soldiers, their opponents and everything in between with highly toxic dioxins in the process. The consequences of this environmental arrogance reverberate today in children born with genetic disorders and an ongoing high mortality rate of old soldiers.

Today, Bay of Plenty. An alien invader is threatening our livelihood, and we are about to respond in the age-old tradition of a full frontal chemical assault with inadequate tools.

Let's not beat around the kiwifruit vine. PSA is our earthquake and may be just as devastating, economically at least. It's just that the broken buildings are not so obvious.

One proposed solution, supported by Zespri and MAF, is to hurl toxins at the vines. The detail is shrouded – I have yet to see reporting and analysis in the media of the proposed spray regime. But it could include a heavy metal known to accumulate in the soil (copper), and bactericides that many of us have taken at some time in our lives to repel invaders (we know them as antibiotics, such as streptomycin).

These toxins will be used in much greater quantities than previously, but apparently that is ok because they are already approved for use in agriculture.

Bactericides have been a mainstay of medical intervention since the discovery of penicillin. They are also used routinely for spraying on pip-fruit, and in the diets of many farm animals.

But they have a use-by date, because the critters that they kill develop immunity rather quickly. That becomes a major problem for all of us as resistant strains of bacteria appear in our hospitals and elsewhere. Our health and agricultural systems are both therefore under pressure to reduce use of antibiotics.

The Europeans at least will not allow importation of honey that contains chemical residues, and the Swiss have shown that such residues are likely from a spray regime such as could occur here.

If you are a beekeeper who pollinates kiwifruit vines, and your key exportable product is under threat. Well, you are likely to take your bees elsewhere.

The consequence – reduced pollination, an uneconomic kiwifruit crop, and it doesn't really matter if your vines are infected with PSA or not because your business is failing anyway.

Many of us live among the kiwifruit vines. Any intensification of spraying will make it difficult for the growers to limit their spraying to windless days. Spray drift, always a problem anyway, is likely to be worse, and some of that spray could contain antibiotics that you might prefer not to ingest when you are healthy.

Even worse is that the available spray options are delaying tactics. They will not kill PSA. Rather, spraying might slow the spread of the disease and give a somewhat better harvest this year than will otherwise be the case.

Vietnam showed that chemical warfare is not a solution. The consequences are long-term, wide-ranging, and may involve direct threats to human health. PSA is a nasty bullet, but a frontal chemical assault threatens all of us. Yes, we need to support our growers, but not like this.

Want to know more? Go to: http://www.kvh.org.nz/pestintroduction