Abstract

The effect of exposure of pesticides and formulated products to atmospheric conditions, particularly to high summer temperatures is considerable. At Rothamsted, Burt and Ward (1955) have explained the rapid volatalisation of D. D. T. in summer as due to high temperature. Cases of adverse effect of high temperature favouring the inactive isomer of organo-phosphorus compounds which are isomeric mixtures of thions or thionol are reported from U. S. A. Materials are imported out of season or delayed in transit. Importers get surplus stocks and dump the stocks lest the users preference should change in the coming season or hoard the pesticides. All these entail storage of such pesticides for considerable time. Wallace and Martin (1954) reported such lapse of considerable time between the date of manufacture and the date of use in the field for crop protection chemicals in U. K. and Commonwealth countries. In India, large stocks of pesticides are held by several agricultural depots in the different States and a variety of pesticides are stored for long periods. Information on the keeping quality is essential for advice on the purchase and storage, of pesticides by Government and ryots. The Pesticide Testing Laboratory at Coimbatore took up investigations on this aspect, adopting the usual methods of storage of the pesticides handled in the agricultural depots and the results are presented.

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