IRRI calls for a ban on insecticides in rice production

To prevent devastating insect pest outbreaks in rice that cause millions of dollars of damage, the International Rice Research Institute (IRRI) has called for a ban on certain insecticides in rice production as part of its new Action plan to reduce planthopper damage to rice crops in Asia.

At a conference in Hanoi, Vietnam, (Threats of Insecticide Misuse in Rice Ecosystems – Exploring Options for Mitigation), held on 16 December 2011, IRRI brought together leaders in the rice industry to advance towards a “greener game plan” to manage brown planthoppers, which are one of a rice farmer’s worst fears. Considered a major scourge in rice-producing countries, planthoppers in large numbers cause considerable damage by sucking sap from rice plants, causing them to wilt and die. They also transmit three viral diseases that stunt rice plants and prevent grain formation.

Dr. K.L. Heong, an insect ecologist at IRRI explains that planthopper outbreaks occur when there is a breakdown in ‘ecological resilience’ of a rice farm. Beneficial predators such as spiders and bugs that feed on planthoppers are part of a natural system of ‘checks and balances’ that keeps planthopper populations below outbreak levels, and when this natural balance is disrupted, such as through the indiscriminate use of insecticides that inadvertently exterminates many beneficial insects that prey on planthoppers, planthopper outbreaks occur.

Also, growing three rice crops a year or using the same varieties over a large area and for a long period can lead to pest outbreaks due to the adaptation and buildup of pest populations.The new action plan to reduce planthopper damage to rice crops in Asia recommends two major principles – first to enhance biodiversity and second to regulate the marketing and use of insecticides, including the banning of certain outbreak-causing insecticides in rice.

Three months ago, Thailand banned the use of two insecticides in rice – abamectin and cypermethrin – because they are known to be major causes of planthopper outbreaks. In March this year, the Vietnamese province of An Giang started adopting ecological engineering practices such as growing flowers in nearby paddies to nurture planthopper predators.

Excerpted from the IRRI News & Events pages at http://irri.org/news-events/media-releases/stop-abusing-insecticides-in-....

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