Abstract
THE use of D.D.T as an agricultural insecticide has been investigated, by G. A. H. Helson and T. Greaves J. Coun. Sci. and Ind. Res., 18, No. 4, Canberra, Australia, November 1945). They find that it is effective against a variety of lepidopterous pests and also certain aphids, including Myzus persicœ and Macrosiphum gei, which can act as vectors for virus diseases. D.D.T. was ineffective against the cabbage aphid Brevicoryne brassicœ, woolly aphis and red spider. On the debit side, bees were seriously affected by this insecticide when visiting the flowers of sprayed bean plants. The experiments were on varied scales, from laboratory tests to field trials, and several methods of application were used. D.D.T. dusts were also found by T. Greaves (ibid., 18, No. 2, May 1945) to provide the best control for a number of cabbage pests in north Queensland. Lead arsenate and calcium arsenate were also effective, but it would seem necessary to apply all three substances only to the early stages of growth of the crop, as they are toxic to man and higher animals. R. F. Powning (ibid., 18, No. 2, May 1945) has evolved a method for the analysis of D.D.T. and pyrethrins in kerosene-based sprays. The two insecticidal components are separated by passage through a column of alumina. D.D.T. passes through, and is then boiled with alcoholic caustic potash to liberate hydrochloric acid, which can be titrated with standard silver nitrate solution. Pyrethrins are liberated from the alumina and estimated by the usual methods. Wheat stored in bulk is sometimes attacked by Rhizopertha dominica and other insect pests. F. Wilson (ibid., 18, No. 2, May 1945) has shown that such outbreaks can be largely controlled by applying finely ground magnesite or dolomite to the surface of the mound. Smaller infestations can be dealt with by fumigation with carbon disulphide or ethylene dichloride.
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Insect Control in Australia. Nature 158, 940 (1946). https://doi.org/10.1038/158940c0
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DOI: https://doi.org/10.1038/158940c0