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Current pesticide status for production of safety agri-food
Currently there is a great increase in concern about the safety of food we eat and the potential hazards arising from contamination with synthetic pesticide residues on crops. In general, consumers tend to believe that synthetic pesticides and there residues in crops are dangerous to our health. On the other hand, less attention has been paid to the naturally occurring toxic substances in crops, which may cause or contribute to illness in humans.
The Korean peninsula is very hot and humid during the summer season. This environment is good for the growth of various kinds of pests and pathogens as well as crops. Therefore, Korea has been one of the most intensive pesticide consuming countries of the world, an attractive market for multinational pesticide companies. In order to control the diseases, pests and weeds effectively, the use of pesticides in agriculture is inevitable. The pesticides protect the reduction of production from diseases, insect pests and weeds. Furthermore, they provide the stable food and crop supply by improving the quality. Thus, the pesticides are the most economical and safe substance to replace and cover the shortage of rural work force, which gets more and more serious.
Pesticide industry in Korea has just a short history of 50 years. Taking the procedures of the import, adoption and imitation of the foreign technologies, five compounds were synthesized newly by our technology and registered as insecticide, fungicide and herbicide. Until now the most of pesticide technicals were imported from foreign countries with high price. The imported technicals are formulating with adjuvant in manufacture factory. From the 1970s a part of technicals which is expired patent are synthesizing by our own technology.
Totally of 1,230 items has been notified to be used as pesticide by the government at 2008. The pesticide production in 2008 was 21,168 M/T as an active ingredient. The amount was divided 17.5% for paddy rice, 45.4% for horticultural plants, 26.2% for weed and 10.9% for others. By formulation, emulsifiable concentrate is 46.3%, wettable powder 32.6%, granule 17.5%, dust 0.8% and water soluble powder 0.7%. The total amount of imported pesticide was 443,362 thousand dollars. Among them the technical grade is 77.4%, intermediates for synthesis 4.1%, formulation 18.5%. The technical grade was divided with fungicides 28.7%, insecticides 34.2%, herbicides 26.2% and others 10.9%. The major importing countries are Japan 29%, Germany 15.2%, United State 15%, China 12.6%, Swiss 8.4% and others 29%. The local production ratio of technicals is 10.6% of the required technicals in Korea. On the other hand, Korea is exporting some technical grade and formulations to several nations. The agrochemical market value of Korea in 2008 was 27,586 thousand dollars.
The ideal pesticide would be toxic only to the target organism, but unfortunately this cannot often be achieved and most pesticides are to some extent hazardous to other organisms also and, therefore, potentially harmful to those handling them. At present 2008, the maximum residue limit (MRL) for 399 pesticides was established in all crops. And the standard for safe use for 800 items except herbicides was also established in each crop. Every year, Korean government is monitoring the residue level of pesticides to agricultural products for safety of consumers. The classification of pesticides toxicity by the Pesticides Management Law is based primarily on its acute oral and dermal toxicity to test animals. This hazard classification of Korea is following the method of WHO. The hazard class is divided into 4 groups; extremely hazardous, highly hazardous, moderately hazardous and lowly hazardous. Among 1,230 items including 28 items of biopesticide using in Korea, there is no extremely hazardous group, 17 items in highly hazardous group, 175 moderately hazardous and 1,038 lowly hazardous.
Apart from classification system by acute toxicity, to minimize the side effects caused by pesticides we have another system prescribing definitely the enforcement degree of crop-residual, soil-residual and water-residual pesticides. Crop-residual pesticide is legally defined as the agrochemical that its terminal residue level in crop harvests exceeds the national maximum residue limit. The residual pesticide of which its persistence is evaluated to have longer than 180 days of half life in soil and the residual impacts on the second cropping is recognized, donates as the soil-residual pesticide. And both of crop and soil residual pesticides are prohibited to register for use. Water residual pesticide of which the fish toxicity (TLm, 48hrs) to the carp is less than 0.1ppm is also legally regulated and banned for use in paddy field.
What kinds of pesticides are required for the future of Korean agriculture? Everybody will reply. "They must have the high activity, be safe and without harmful effects to the animals and environment". But actually the development of ideal pesticides in Korea is very difficult owing to invest of lots of money and time. So we are using the technology of molecular design for toxicity reduction of already existing pesticides, and research for development of biopesticides by the bioengineering technique using plants and microorganism. To use pesticides effectively, we have to research and evaluate of integrated control measures including development of biological, enzyme and hormone manipulation, and mechanical controls resulting in pest management concepts. For the future, it is necessary to produce and use more effective and more selective pesticides.
Over the development of synthetic pesticides from 1940s there have been significant changes in the tools available for research and development of pesticides. Research on pesticides has gone from spray and prays to high throughput screening on in vitro targets. Analytical techniques of pesticides now allow easier identification of metabolites and degradation products, whilst parts per trillion can be routinely determined. These changes have been largely driven by advances in computing power over the past decades. Similarly, the modeling for development of new pesticides that can now be carried out would have seemed impossible 50 years ago. Information today is also much more readily accessible than before, the internet is a tool which has come of age and is the repository of a large amount of information. Communications have similarly changed with personal mail allowing instant communication with fellow scientists.
In the future, international cooperation will be more needed for the exchange of related and updated information in safety evaluation and development of pesticides.
