Abstract
SOME useful information about the phytopathological uses of the new insecticide D.D.T. (dichlorodiphenyl trichlorethane) has been given by H. Martin and R. L. Wain (J. Boy. Hort. Soc., 69, Pt. 12, Dec. 1944). This substance, at insecticidal strength, is harmless to man and farm animals, but acts fcoth as a contact and stomach poison to insects. D.D.T. could probably replace lead arsenate in the combined spray with lime sulphur, without any objectionable sludge of lead sulphide. Perhaps its most outstanding possibility, however, is its use as a persistent contact insecticide. It is unaffected by light and moisture, in contrast to the pyrethrins and rotenone, and offers the horticultural possibility of applying a contact insecticide at any convenient period—not, as hitherto, when the insects are actually exposed upon the plant. This should provide a useful method of control for such pests as apple blossom weevil and the leaf miners, which are usually protected from any direct spray, but move about the plant for certain limited periods. D:D.T. does not seem to have any egg-destroying properties, and is somewhat slow in action, but these defects are small in comparison with the positive benefits. A short anonymous account following the above reference directs attention to a new thiocyanate winter wash. The toxic agent is β-butoxy-β'-thiocyanodiethyl ether, and this is incorporated with petroleum oil. Thiocyanate washes are non-poisonous to human beings, domestic animals and poultry, are more convenient in use than dinitro-ortho-cresol (D.N.C.) and give a good control of woolly aphis, which has hitherto eluded all attempts to control it by spraying.
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Insecticides. Nature 156, 168 (1945). https://doi.org/10.1038/156168b0
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DOI: https://doi.org/10.1038/156168b0