Published online by Cambridge University Press: 10 July 2009
An investigation was made into means of increasing the effectiveness of the usual DDT-containing residual sprays with a kerosene base.
The common house-fly, Musca domestica, was used as biological material.
It was found that there exists a distinct relationship between crystal size and residual toxicity. Finely crystalline residues from DDT solutions in volatile solvents, such as xylene, proved to be considerably more toxic than coarsely crystalline residues from DDT solutions in less volatile solvents, such as kerosene. Addition of small quantities of coumarone resin to a DDT solution in kerosene was found to reduce the size of the DDT crystals and to increase the toxicity considerably.