Insects devastate Thailand's rice crop, institute says

Feb 8, 2010, 2:52 GMT

Bangkok - Excessive use of fertilizers and pesticides and other poor farming practices have led to an insect plague in Thailand's rice fields that was predicted to reduce yields by 30 per cent in vast areas, the International Rice Research Institute warned Monday.

'This is the worst outbreak of brown planthoppers I have seen in my career since 1977,' said Manit Luecha, director of the Chainat Rice Seed Center.

'Most of the paddy fields - probably more than 1 million hectares - will suffer rice yield losses of more than 30 per cent,' he predicted.

Thailand is the world's largest rice exporter. Last year, it shipped 8.6 million tons abroad, earning the country 5 billion dollars in foreign exchange.

The institute blamed the current plague of brown planthoppers, or BPHs, on poor farming practices triggered by a jump in world rice prices in 2008.

'To prevent outbreaks, we must restore the natural environment and biodiversity to keep BPH numbers below economically damaging levels,' institute insect expert KL Heong said. 'To achieve this, farmers will have to use pesticides more strategically and adopt ecological engineering principles.'

The institute recommended that Thai farmers adopt pest-management practices such as growing plants between rice paddies that attract planthopper predators, such as spiders, crickets and parasitoids.

The rice institute, based in the Philippines, also advised farmers not to apply fertilizer in excess because overfertilized crops tend to promote planthopper growth and to limit the use of pesticides to control leaf-eating insects because those products kill the planthoppers' natural predators.

'Last year, high rice prices motivated Thai farmers to grow rice continuously, fertilize their rice more in an effort to boost yields and attempt to protect their investment by spraying more pesticides to keep leaf-eating insects at bay,' Heong said.

'This combination of practices helped cause the current BPH outbreak in Thailand,' he said.