POVERTY: THAILAND: Rice pests multiply post-floods

BANGKOK, 12 March 2012 (IRIN)

 Photo: Sylvia Villareal/IRRI
Of pests and pesticide in Thailand: a province hit by the brown planthopper

Heavy flooding across parts of Thailand in 2011 has fuelled outbreaks of a rice pest that can decimate harvests, experts say.
The pest, known as brown planthopper (BPH), transmits two viruses that hit yields as well as eating away at rice plants.
"The floods have certainly made things worse," Kong Luen Heong, principal scientist for the Manila-based International Rice Research Institute (IRRI) told IRIN.
"Moreover, they will impact [on] upcoming harvests as well."
"BPH is attacking the rice bowl of the country for the eighth time in a row [over the past four years]," said Kukiat Soitong, from the Thai government's Rice Department, based in the Agriculture Ministry, adding that "150,000 hectares have already been seriously damaged in the central plains, in the basin of Chao Phraya river".
Affected provinces lost 30 percent of their rice production due to BPH in early 2010, amounting to around 1.3 million tons for the country, or more than 15 percent of the nationwide harvest, which takes place twice a year, reported the Rice Department.
According to the Thai Rice Exporters' Association, Thailand produces 4-5 percent of the world's rice, and is the largest exporter, with 10.8 million tons in 2011.
Last year's flooding, which affected more than two million people across 28 provinces and damaged more than two million hectares of farmland, worsened the longstanding pest problem by drowning natural enemies of BPH, including insect parasites and spiders.
"Because of the floods and the killing of BPH's natural enemies, farmers are more dependent on insecticides for several seasons. And the fact is that using insecticides makes BPH even stronger," added Kukiat.
Most insecticides kill BPH's natural enemies, rather than BPH itself. The brown planthopper has an "unmatched" capacity to become resistant to any molecule used against it, according to Keng Hong Tan, a retired entomology professor based in Malaysia.
He says the pest has even developed resistance to one of its own hormones when applied as a control measure.
And while IRRI and Thailand's Rice Department launched a campaign in July 2011 to ban the two insecticides most often used in rice cultivation, cypermethrin and abamectin - known to cause BPH's resurgence - the ban is unlikely to have a significant impact.
"This campaign will have limited immediate effects because of the floods," said Heong. "It will take some strong will to break the vicious circle that helps BPH."
Yet banning insecticides is the only way to control BPH outbreaks in the long term, said Ho Van Chien, director of the Vietnamese government's plant protection centre for southern Vietnam.
According to IRRI, BPH damaged hundreds of thousands of hectares across Asia, leading to hundreds of millions of dollars in lost production.
Since 2009, Bangladesh, Cambodia, China, India, Indonesia, Japan, Malaysia, Myanmar, the Philippines, Thailand and Vietnam have been severely affected at least once.
"BPH puts the whole rice ecosystem in jeopardy," said Erma Budiyanto, director of plant protection in Indonesia's Ministry of Agriculture.
"There could be a humanitarian situation because of this pest in the future if insecticides remain as widely used as today," said Heong.
http://www.irinnews.org/Report/95058/THAILA

MALNUTRITION: THAILAND: Insect influx threatens rice production

BANGKOK, 24 August 2010 (IRIN) - Experts warn that a significant increase in the numbers of brown hoppers, a rice pest, in central Thailand, threatens production. "The current situation is not good," KL Heong, an insect ecologist from the International Rice Research Institute (IRRI) [http://beta.irri.org] told IRIN in Bangkok. "Looking at the number of hoppers caught in light traps over the last two months, it's clear that a massive immigration has occurred." Light traps are used to measure population levels of migrating hoppers within a 9.1-15m radius. On an average night, a light trap will catch 10-20 hoppers. During migration peaks (twice a year), this can rise to about 2,000 per night. Heong recently spent three days visiting fields, farmers and agricultural experts in Suphan Buri, Chainat and Ang Thong provinces where he saw traps with up to 40,000 hoppers and "nymphs hatching all over the place". Anything above 10,000 is alarming, Heong says. "This will peak around December. I expect 30 percent losses at least in most rice fields," Heong warned. The hoppers, known scientifically as Nilaparvata lugens, remove plant sap with their mouths, causing the tillers - any of the extra stems or culms in a rice plant that arise from its base - to dry out and turn brown, a condition called "hopper burn". It also transmits two viruses, "ragged stunt" and "grassy stunt", both of which render the rice crop infertile. According to the Ministry of Agriculture, from November 2008 to May 2009 (the dry season) Thailand lost 1.1 million MT of rice due to hopper outbreaks, costing an estimated US$275 million. Thailand, the world's top exporter of rice, produced more than 27 million MT in 2009, says the UN Food and Agriculture Organization. With similar insect population numbers this summer, the Ministry of Agriculture warns of at least the same losses this year. "Our estimates on production will have to be reduced," Wantana Sriratanasak, an entomologist with Thailand's Department of Agriculture, said. Pesticide use According to Heong, extensive pesticide use by farmers is the primary reason for the infestations. Pesticides have a limited effect on plant hoppers but kill off their natural predators, including several species of spiders. The insects have a high migratory ability and fast reproduction rates, exacerbating the threat. Thai authorities are looking for regional and practical solutions to manage and prevent future outbreaks. "We've been collaborating on a project for two years with China and Vietnam. Both countries still have a serious problem with outbreaks," Sriratanasak said. The focus will be on improving biodiversity while simultaneously reducing pesticide use. Vietnam lost four million MT in 2007 because of outbreaks, while China regularly loses a million hectares a year. The Rice Department is working to encourage local farmers to reduce spraying, Kukint Soitong, a senior expert in the department confirmed. "We have to change farmers' chemical use," he said, "but it's not easy."