Chemicals losing out to genetics

By SIMON COLLINS

Scientist Tony Conner hopes that McDonald's and Kentucky Fried Chicken made a big mistake when they decided three years ago to stop buying genetically modified potatoes.

As soon as he is allowed to after October, Conner plans to seek approval for farm trials of potatoes containing two new genes taken from the bacteria Bacillus thuringiensis (Bt) - the same bug that has been sprayed on West Auckland to kill the Australian painted apple moth.

He's gambling that, unlike McDonald's and KFC, New Zealand potato farmers will be keen to plant Bt-infected potatoes because they will be resistant to another alien invader, the potato tuber moth.

"Bt cotton, maize and canola are available overseas," he says. "Bt potatoes have been largely withdrawn from the US market because McDonald's said they don't want genetically modified French fries, despite the fact that they already use Bt soy oil in their salad dressings. KFC said the same."

The result is that New Zealand is now "as far ahead as anyone" with tuber moth-resistant potatoes. Conner believes they will allow farmers to cut back on the chemical sprays which control the moth at present.

Lincoln University Professor Alison Stewart, who heads a new bioprotection technologies research centre which Conner has joined, says similar biological controls - genetically modified or not - will increasingly replace chemicals to control pests and diseases.

Non-chemical techniques hold enormous promise for all farmers, including organic growers for whom "biological" controls mean acceptable "natural" methods.

But genetically modifying plants to fight diseases is quite another matter. Come October, when the present moratorium on genetically modified (GM) field trials comes off, Conner's moth-resistant potatoes look like being the first test of the new regime.

To those in China or India who see GM foods as their best hope to feed growing populations, fighting pests and diseases might seem of marginal benefit. Yet for New Zealand to help in feeding the world, and to protect our environment, pests and diseases loom large.

The painted apple moth, which threatens our vast forest plantations, is just one sign of our vulnerability.

Beekeepers are still struggling with the Varroa mite. A lettuce aphid has forced farmers to abandon thousands of hectares of lettuces. A fungus, onion white rot, threatens the viability of Pukekohe onion farms.

Larger pests endanger our livestock. Our possums carrying bovine tuberculosis are up to 20 times more numerous on each hectare of land here than they are in their native Australia, where predators keep them in check.

Stoats threaten to wipe out the kaka and our national symbol, the kiwi.

"Remaining populations of kaka around the country are just a shadow of what they used to be and are showing 90 per cent-plus males, because the kaka nest in the holes of trees where stoats eat the females," says Forest and Bird conservation manager Eric Pyle.

"Predation of kiwi chicks by stoats is running at 95 per cent. Unless we find better ways to control stoats, we are going to lose the last populations of kiwi and kaka. We have a world-leading pest problem of a scale and dimension that no other country has."

Controlling it is expensive. The painted apple moth campaign is costing $90 million. The Government spends $45 million on possum control and another $15 million on researching better methods to do the job.

In the last year for which figures are available, 1998, we slapped on 3300 tonnes of pesticides. More than 85 per cent of the world's 1080 poison, about 2.5 tonnes a year, is used in New Zealand to kill possums.

Many developed countries, including Australia, have adopted strategies to reduce pesticide use. In Denmark, the Government set a target in 1996 of halving pesticides in a decade, boosted research and appointed advisers to work with farmers, funded by a tax on pesticides. The target was surpassed and they are now cutting use even further.

In New Zealand, the last study found: "The gross quantities of pesticides used in NZ annually have remained relatively constant with the totals in 1985-96 averaging 3700 tonnes [of] active ingredient per annum." The figures were around 10 per cent less in 1983 and 1998.

"In this country people are scared to do anything that makes us look like we are not clean and green," says Dr Meriel Watts of Pesticides Action Network. "Actually we have a serious problem but we are in denial about it."

A year ago this week, the Ministry for the Environment launched a discussion paper, Towards a Pesticides Risk Reduction Policy for New Zealand. This week the ministry analyst in charge of the policy, Ian Cairns, said: "That work has ceased. It's been overtaken by the hazardous substances strategy."

Amendments to the Hazardous Substances and New Organisms (Hasno) Act are due in Parliament at the end of this month, mainly to provide for the conditions under which GM organisms will be approved for field trials or release after October. Pesticide provisions will now be tagged on.

"What it's shaping up to is there have been arguments from business about Hasno creating excessive barriers to the registration of chemicals," Cairns says. "The solution to that is to look at possible improved pathways through the legislation ... It's going to make it easier ultimately in the next two to three years to bring in new and more modern pesticides."

But while the politicians procrastinated, farmers have already started to change. Over the past 10 years, driven by European Union requirements, the kiwifruit industry has changed to the "KiwiGreen" system which has cut the average number of across-the-board chemical sprays from eight a year to three.

"If they do require spraying, they use Bt," says Cathy McKenna of HortResearch, Te Puke. Bt, being bacteria rather than a chemical, counts as "biological" control and can be used even by the 5 per cent of kiwifruit orchardists who have gone totally organic.

Her Hastings colleague, Dr Jim Walker, says apple growers have cut their use of across-the-board chemical insecticides by 95 per cent since 1996, with organic orchards now up to 9 per cent of the total. A Californian parasite, Pmac, has been imported to attack the apple-eating mealy bug.

HortResearch has also hit on the ingenious idea of spreading female hormones of moth pests through an orchard to confuse the male moths. In West Auckland, to complement the aerial spraying, it has released 20,000 male painted apple moths sterilised by irradiation. They are mating with the female moths who do not know the males are sterile, so they are failing to breed.

"We are over-flooding the wild moths by a ratio of at least 80:1," says the institute's biosecurity leader, Dr Max Suckling. "The trap catch was zero last week, so the population has been seriously reduced. As the density gets lower, the ratio of our sterile males increases."

Philip Manson, science manager of the Wine Growers' Association, says vineyards have cut back on chemicals and switched to "greener" Bt. "Our slogan is, 'New Zealand wine, the riches of a clean, green land,"' he says. "In a vineyard today you will see a lot more understorey plants that are there to provide alternative food sources for the beneficial insects."

Professor Steve Wratten, another member of Stewart's National Centre for Advanced Bio-Protection Technologies, has planted flowers between the vines at Marlborough's Seresin Estate. Bugs that used to eat the grapes now feast on pollen and nectar in the flowers instead.

Taranaki farmer Russell Jordan, who chairs the Vegetable Federation's fresh vegetable sector, says vegetable growers are switching to Bt sprays such as Dow Chemicals' 'Success'. "Organophosphates, which were like a shotgun that blasted everything, were used because there was nothing else," he says. "But public pressure is slowly starting to get them replaced."

He is less sure whether farmers will take up Conner's Bt-modified potatoes or Crop and Food Research's other disease-resistant GM crops including onions, peas and brassicas such as broccoli, cauliflower and Brussels sprouts. "Growers may well be reluctant to use it [GM] because of consumer resistance, but its acceptance will probably be pretty quick in other countries around the world," he says.

Historically, biological methods have had some spectacular successes. Ragwort and St John's wort were both classed among New Zealand's worst four weeds early in the 20th century. Imported beetles have knocked them back to the point where neither is now considered a problem.

Landcare Research expert Lynley Hayes says scientists have introduced six new bugs since 1989 to replace chemical sprays for gorse, with only limited success so far.

Landcare is about to apply to the Environmental Risk Management Authority (Erma) to bring in a South African leaf roller caterpillar to attack a yellow daisy-like weed called bone-seed.

Another crown institute, AgResearch, has brought in tiny wasps from Europe and South America to attack grass-eaters such as the clover root weevil and the Argentine stem weevil.

Its biocontrol science leader, Dr Stephen Goldson, is working with the British Army to adapt a military sensor to look for unwanted bugs coming over the wharves.

Landcare, AgResearch and Australian scientists are all working on various biological methods to control possums. Landcare has brought in carrots that have been genetically modified in the US to make possums infertile when they eat them.

AgResearch is trying to genetically modify a worm in the possums' bodies to produce a protein that will damage their growth, life or reproduction. "We have worked out the genetic techniques to modify it," says its science general manager, Dr Paul Atkinson. "What we don't have is certainty that the public would accept that. It will be five or 10 years before we would be ready to deploy it."

In the Green camp, Watts welcomes most of the thrust towards biological controls - but not modifying plants genetically to resist disease. She points to a US study showing that genes inserted into crops to make them resistant to Monsanto's Roundup weedkiller have spread into 200 weed species.

"They have had to return to weedkillers that are a lot more damaging than Roundup was, such as Paraquat," she warns.

However, cabinet papers published on Thursday argue that such risks can be limited by setting conditions on GM crop releases, such as specifying where they can be planted and how far away they must be from non-GM crops.

Conner and Stewart both see GM crops as only part of integrated pest management.

Their new centre, though based at Lincoln University, includes scientists from four other universities and six research institutes.

The Government is giving it $2.7 million a year for the next six years, plus money to buy equipment and build a $3.5 million climate-controlled greenhouse or "biotron" at Lincoln.

"We have been working in silos for 10 years on different developments. The aim is to break down all those barriers, from organics to high-tech biotechnology," says Stewart.

"The philosophy is, let's understand more about the underlying molecular basis of how pests and diseases cause damage, and see if we can come up with innovative ways of the plant being able to suppress them.

"Some may be transgenic crops. Or it might be another idea that involves no GM technology at all."

National Centre for Advanced Bio-Protection Technologies