China's Rice Herbicide Market Looks forward to New Products    

By Zhang Weinong, Nantong Pesticide Market Information Center  

China has a rice planting area of about 33.3 million hectares. According to survey data, there are more than 20 types of common weeds in China's rice fields. Among them, barnyard grass (echinochloa crusgalli) is the most common vicious weed. Over 6.7 million hectares of rice fields in China are affected by it.
   Chemical way weed control in the rice field began to become popular in China in the early 1990s. Back then, amide herbicides like butachlor emulsion concentrate (EC) and acetochlor powder and carbamate herbicides like molinate and benthiocarb were widely used in rice fields. Later, sulfonylurea herbicides like bensulfuron-methyl and metsulfuron-methyl and the mixtures of amides and sulfonylurea herbicides were widely used for weed control in China's rice fields.
   With the advance of seedling raising patterns and the rice planting technology, chemical way weed control in rice fields becomes more difficult, and the requirements for the safety and application technology of rice herbicides are higher. At present, three major problems for chemical way weed control in rice fields must be resolved. First, there are almost no rice herbicides that can control both barnyard grass and other weeds. Secondly, traditional rice herbicides like ouinclorac have a reduced control effect on barnyard grass. But there are no effective alternative herbicides available for the control of barnyard grass till now. Currently, there are over 30 registered enterprises in China to produce quinclorac active ingredients and formulations. They have a total quinclorac formulation sales volume of 1 500 tons per year. After more than 10 years of continuous use, barnyard grass has had a strong resistance to quinclorac. Even if its dosage is increased, quinclorac is not as effective in controlling barnyard grass as before and even has zero effectiveness. In addition, butachlor & bensulfuron-methyl containing herbicides have high activity, good safety and low cost, but such herbicides are somewhat less effective in controlling barnyard grass, having a control efficiency of only 65% -76%. Thirdly, the long-term continuous use of bensulfuron-methyl and its mixtures have also made weeds produce a resistance to them. In direct-seeded rice fields, the occurrence and damage of weeds have become increasingly serious. Chinese rice farmers tend to use bensulfuron-methyl and its mixtures with butachlor, acetochlor and MCPA as well as the mixtures of quinclorac with bentazone, propanil, benthiocarb and bensulfuron to control weeds. This can easily make the weeds to produce resistance to these herbicides. This has become a difficult problem that demands a prompt solution for direct-seeded rice fields.
   In recent years, a number of multinational companies' rice herbicides enter China's market and have already occupied a certain market share in China. According to reports, three rice herbicides of the U.S. Dow AgroSciences LLC, that is, Clincher (cyhalofop-butyl), Grasp (2.5% penoxsulam) and RebelEX (a mixture of penoxsulam and cyhalofop), have good control effect on barnyard grass, Monochoria grass and Eleusine indica in rice fields. Grasp have excellent control effect on resistant barnyard grass. The sales of these three herbicides of Dow AgroSciences was stable in 2009 and will reach RMB100 million in the Chinese market in 2010. The Broadhead rice herbicide launched recently by the United States' FMC Corporation in the Chinese market has especially good control effect on barnyard grass and Leptochloa chinensis in direct-seeded rice fields and crabgrass in dry direct-seeded rice fields and is cheaper than RebelEX. FMC has become the only competitor of Dow ArgoSciences in the Chinese rice herbicide market. South Korea's LG Corporation's 10% halosulfuron-methyl has relatively high control effect on barnyard grass and also seizes a certain market share in the Chinese rice herbicide market. The Chinese rice herbicide market will be a touchstone for the herbicidal effects of these imported herbicides.