CALL it the power of the SMS-vine.

A text message warning against eating oranges flooded cellphones across China on Oct 20. It read: "Tell your families and friends not to eat oranges.

"Fruit-fly maggots have been found (in oranges) in Guangyuan, Sichuan province."

Retailers and farmers were reduced to tears - even though there was only a limited maggot problem and the bugs were harmless to humans. Orange sales have picked up a bit after three weeks of government clarifications, but images of rotten oranges and weeping farmers were still on TV on Tuesday.

Said Mr Deng Xiuxin, a specialist in the study of oranges with the Chinese Academy of Engineering: "What happens if a person swallows a maggot accidentally? Some worms in plants can even be eaten as food. There's no need to worry."

But farmers in orange-producing provinces like Sichuan, Hunan, Hubei and Jiangxi have had to destroy thousands of tonnes of mandarin oranges. A China Central Television report put the total loss at over 10 billion yuan (S$2.2 billion).

Ms Liu Xuezhen, a farmer in Shimen county, Hunan, had 45,000kg of fruit ready for picking in her orchard, but she struggled to find any takers.

"If no one buys my oranges, my family will be left penniless," she said. She eventually found a buyer - after accepting just 10,000 yuan for her oranges, which she could normally sell for 40,000 yuan.

Orange-dealer Chen Shouyun, in Chengdu, the capital of Sichuan, said: "Last week, I didn't sell even 1kg of oranges when I used to sell 5,000kg a day."

The central and local governments have responded by explaining that the maggot outbreak is confined to a particular area and that there is no health threat.

The day after the SMS surfaced, on Oct 21, the Sichuan provincial government said a farm in Wangcang county had reported the failure of its mandarin harvest due to fruit flies. A survey found that 9 per cent of the county's 68,000 orange trees had been affected.

"Talk of a large-scale outbreak is just a rumour, and all affected fruit have been destroyed," said Mr Tan Jiaxing, a senior official of the provincial agricultural department.

To prove the fruit were safe, high officials ate them in public.

But such tactics could not match the viral power of the text messages.

Said Mr Chao Naipeng, professor of communications in Nanjing University: "The panic and anger caused by news of maggots in oranges are strong enough an impetus for people to forward the SMS to others.

"If such information is spread through the mobile phone, it'll spread too fast for governments to take any counter- measures," he said.