International Rice Research Institute
Los Baños Philippines
The brown planthopper problems in Central Thailand have intensified. The Bangkok Post reports that Thailand could reduce the 2009/10 rice production forecast of 23.51 million tonnes by 1.1 million tonnes. Starting in July 2009, hopperburn has spread to 18 provinces in the Central Thailand. Some of the Northeastern rice areas are also affected. The Bangkok Post reports that the Ministry of Agriculture is seeking for more funds to control these outbreaks. Provincial governors are also asked to release emergency funds to control BPH.
My greatest concern is that most of the funds will be used to purchase and distribute pesticides in attempts to eradicate the pest. If this happens, the BPH outbreaks are likely to intensify in some areas and spread to infest more areas and the coming season’s crop, thus prolonging the BPH attacks. Using pesticides to control brown planthopper outbreaks is like using gasoline to control fire. Unless the pesticides to be bought are restricted to those effective for BPH control and have less harm to ecosystem services, rice farms can become more vulnerable to hopperburn. It is likely that the pesticide market will determine the pesticide supply and most likely many of the common compounds that have the bigger market shares will be distributed, like abamectin and cypermethrin. These insecticides have devastating effects on the aquatic, predator and aquatic fauna which form the foundation of natural biological control. Providing subsidized pesticides will contribute significantly to farmers’ pesticide dependency that will further add to development of insecticide resistance, more outbreaks, environmental pollution and farmers’ health problems.
The extra funds can be used instead to prevent future outbreaks. Planthopper problems are insecticide induced. Thus increased efforts in educating farmers to make better decisions, select when to avoid using insecticides, increase on-farm biodiversity and appreciate the natural control forces will be more useful and sustainable. We have shown that biodiversity in rice farms can be restored in 1 or 2 years as soon as the destructive pesticide forces are removed. Otherwise the brown planthopper will remain a threat to rice production breaking out when conditions are appropriate. With the expected elevated temperatures due to climate change, these outbreaks will become more frequent and intense.