Farmers bite back after fire blight crisis

Fire blight gives infected trees and fruit a blackened appearance

Last year fruit grower Edwin Huber feared for his farm's existence after fire blight, a highly destructive bacterial disease, swept through his apple orchards.

This content was published on August 2, 2008 - 14:03

Thousands of fruit trees were infected in Switzerland in 2007 – the worst ever year for fire blight – causing millions of francs worth of lost crops. This year an antibiotic has been used for the first time to combat the disease – with positive results.

Huber's seven-hectare farm is in Neukirch-Egnach, an idyllic village nestled in the rolling fields above Lake Constance in northeastern Switzerland.

This is the heartland of Swiss fruit growing – with one in three Swiss apples eaten in the country coming from the area. For Huber, a fruit grower all his life, fire blight was a disaster.

"I had to clear one third of the farm, 6,600 trees last year, and 80 per cent of my tree nursery," Huber told swissinfo.

Fire blight can live up to its name, giving trees a blackened, singed appearance. Carried by the wind or insects, it spreads quickly. In a worst-case scenario, it can kill an orchard in one season.

In 2007 125 hectares of infected trees were cut down in Switzerland, with 65 hectares alone in the Thurgau region around Huber's farm. The authorities had to pay SFr30 million ($29 million) countrywide in compensation.

The experience gave Huber and his family many sleepless nights. "I didn't know whether I would be a fruit grower any more at the end of the year," he said.

Antibiotic treatment

With fire blight threatening again in 2008, the Federal Agriculture Office announced it would allow the antibiotic streptomycin to be sprayed onto flowering trees in the spring - when they are the most susceptible to the infection.

Streptomycin is currently the most effective tool against fire blight. But its use is disputed – antibiotic-resistant strains of fire blight have developed – which explains the agriculture office's initial reluctance. Concerns have also been raised over possible harm to humans, animals and the environment.

Neighbouring Germany and Austria have used the remedy for years, but only under strict conditions.

So far the antibiotic has been effective, says the fruit industry's body, the Swiss Fruit Association, which recently organised a trip around treated orchards for journalists and experts to see the results for themselves.

Less than ten hectares of trees were cleared in the first half of 2007 in the farms in northeastern Switzerland which used streptomycin.

Visible results

Walking along the rows of treated trees at Huber's farm, fruit can be seen on green and healthy-looking branches. Only 20 per cent of these trees had to be felled this year.

But in the rows where alternative methods were used, two thirds of the trees succumbed to the disease. Those remaining look to be struggling.

"Without streptomycin we would certainly have been in the same position as last year," says Huber, who is also head of the Thurgau Fruit Association.

But despite this success, fire blight continues to spread in Switzerland, with the first case being recorded near Lake Geneva, western Switzerland, earlier this year.

"We will absolutely need to use streptomycin in the next years until more efficient alternatives are found," said the Swiss Fruit Association's director Bruno Pezzatti.

"Even better are species which are resistant to fire blight," he said, adding that research was still in progress.

Problems

But not everyone is happy about the use of streptomycin. "The winners include the fruit growers because they get their problem under control," said Richard Wyss, president of the Swiss German and Romansh Association of Beekeepers.

"On the losers' side are the beekeepers because it cannot be ruled out that honey becomes contaminated with streptomycin and cannot be sold," he told swissinfo on the sidelines of the orchard visit.

Honey in the three most fire blight-affected regions in eastern and central Switzerland has been tested.

Only very few samples were over the prescribed limited of 0.02 milligrams of streptomycin per kilogram of honey. All honey over 0.01 mg/kg, a voluntary limit, was destroyed and the beekeepers compensated.

For Wyss, the antibiotic cannot be not a long-term solution as consumers expect a 100 per cent natural product. More research to find alternatives is needed, he said.

However, the use of the antibiotic does not appear to have affected customers' taste for fruit. Sales of Swiss apples and pears actually rose last summer and winter, according to Pezzatti.

"We think it's because people have understood that it's an emergency situation when this remedy is needed," he said.

swissinfo, Isobel Leybold-Johnson in Thurgau

Fire blight

The bacterial disease originated in North America and spread to Europe. It reached Switzerland for the first time in 1989 and has steadily spread since 1995.

Crop losses resulting from blossom infection are severe and young trees can be killed by progressive disease within a single season. Due to its quarantine status, even single fire blight infections may mandate eradication of entire orchards.

Beekeepers are concerned about contamination because bees collect nectar during the flowering period, which is exactly when the trees are sprayed with streptomycin.

The Swiss Fruit Association says it will ask for the limited use of streptomycin to be continued in 2009.

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Swiss infections

Thurgau, Lucerne and St Gallen are the cantons that have been the most affected by fire blight. They account for 70% of Swiss apple production.

More than three out of four streptomycin treatments took place in these cantons. The treatment took place in May 2008 and was not permitted in tree nurseries.

Particularly hard hit are organic farmers. Alternative methods to streptomycin have not been so effective, according to experts.

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