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The S component of Blasticidin has proved to be a most effective agricultural chemical for the prevention of rice blast, a serious fungal plant disease. Blasticidin-S successfully controls the growth of mycelia, which form spores and propagate the disease. Its concentration is 100 times greater than that of mercury-based fungicides.
Blasticidin-S is a colourless needle crystal with a melting point of 236 ºC and molecular weight of 300 to 450; molecular structure has yet to be determined. The crystals dissolve in water and acetic acid but not in organic solvents. Blasticidin-S is stable against heat and ultraviolet light and is of low toxicity to human and aquatic life.
Sumithion was developed by the Sumitomo Chemical Company in 1960. It is a very effective insecticide against the larvae of the rice borer, the house fly, cockroaches, the rice stinkbug (Oebalus pugnax), caterpillars of the cabbage butterfly (Pieridae) and other domestic and agricultural pests.
The toxicity of Sumithion is low for humans and also for mice up to an oral dosage of LD50 870mg. Sumithion must be applied frequently since it decomposes rather easily and has low residual effect.
DDT is a synthetic insecticide of very high contact toxicity which, until recently, was used on a global scale. It was developed in 1939 by Paul Muller, a Swiss chemist, and its production became highly advanced during the Second World War (1939-1945) in the United States of America. However, it has been discovered that DDT, ingested by livestock and transferred to humans in meat and milk, accumulates in the subcutaneous fat of the human body. At the end of 1969, several countries banned the use of DDT and by the early 1970's it is expected that the use of DDT and another chlorinated hydrocarbon insecticide BHC (see N-16-2-8 following) will cease altogether. However, DDT was a truly important development in its time and a major weapon in the control of malaria. Dr. Muller was awarded the Nobel Prize for Medicine in 1948. DDT is stable against acids but it becomes dehydrochlorinated in alkaline conditions. Decomposition of DDT in air or ultraviolet light is rare. The Sample in the capsule is pp'-DDT 99.8% up.
In 1942, three years after the development of DDT, another powerful synthetic insecticide was discovered : BHC or hexachlorocyclohexane. At the close of the Second World War, in 1945, Japan faced an acute food shortage and BHC was used widely against the rice borer, an insect harmful to paddy piants. BHC was mass produced and the rice yield in Japan increased significantly. Together with DDT and other chlorinated hydrocarbons, BHC came under suspicion in 1969 and its use in Japan and other countries as an agricultural chemical and household insecticide was severely curtailed. It has been shown that the beta isomer in BHC is particularly stable, having a high degree of toxic residue.
BHC is stable against acids, weak against alkalis. It decomposes in the presence of iron ions. The BHC in the capsule is lindane(purified gamma isomer) 99.8% up.
The contents of this site are excerpted from THE OFFICIAL RECORD OF TIME CAPSULE EXPO'70(March 1975). Please note that company and organization names may differ from those of the current ones.
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