INSECTS PESTS.

Star (Christchurch), Issue 16940, 15 January 1923, Page 5

INSECTS PESTS.

METHODS OF CONTROL. (Per Press Association.) WELLINGTON, January 13. The control of injurious insects was the subject of an address delivered at the Town Hall on Saturday evening bv Dr R. J. Tillyard. F.L.S., who lectured under the auspices of the Australasian Association for the Advancement of Science. Dr Tillyard said that man in his efforts to improve his own food supply was always unwittingly making new opportunities for his insect enemies. As an example of this the lecturer mentioned the well-known pest, the codlin moth, which attacked apples. Before the era of. civilisation the little moth lived in the thickets and forests of the northern hemisphere, and its caterpillar bored its way into the inside of the wild crab apple and lived on its contents. With the improvement in the apple by man the cold in moth got its opportunity, and quickly seized the chance to spread and damage all the beautiful varieties of apples which man had produced. Man thus was faced in all directions with problems of his own making and of the very greatest importance to his future welfare, the control of the varies insect pests which interfered with bis food supply. The lecturer then went on to deal with the various methods by which control of pests was attempted, sometimes with signal success, sometimes with disappointing failure. These methods might be classed roughly as mechanical, chemical and biological. Under the beading of mechanical methods the lecturer gave illustrations of a. number of interesting devices which have been made use of, particularly in America, with great success. Two of the most striking of these were tarred paper discs used to control the cabbage root maggot, and ingenious cages for the control of the pine weevil. In the chemical division there were numerous sprays, vapours, dusts and gases for fumigation. The lecturer passed these over fairly rapidly, as ho said they mostly were familiar to the audience, but he mentioned particularly high power spraying used for valuable forest trees in America, and the recent development of spraying from an aeroplane. He also mentioned the recent development of the use of chemicals in the soil, which vapourised ancl gave off gases which repelled certain insects. The chief portion of the lecture dealt with biological methods, which were being improved and brought into use, and which consisted broadly in careful scientific study of an insect pest:, ancl its own numerous enemies, ancl the utilisation of these enemies to control the pest. In this connection lie gave a detailed account of the wonderful work which had been clone in America in the control of the gipsy moth. This moth was introduced from Europe and rapidly began to attack all kinds of forest trees, threatening colossal destruction in the eastern states. Hugje sums of money had been spent in controlling it, and from twenty to thirty different natural enemies, both predatory ancl parasitic, were now being liberated in countless numbers to help to check the pest. After giving other striking examples of the successes achieved by Americans who, he said, were undoubtedly far ahead of the rest of the world in this branch of work, the lecturer went on to give a short account of the more modest, efforts which are being undertaken in New Zealand by the Government biological laboratories in Wellington and by the Caw thorn Institute in Nelson. Of considerable interest in this connection was a detailed account of the introduction, acclimatisation and distribution to all parts of New Zealand of the valuable little parasite of the woolly aphis, known, as Aphelinus mali. The lecturer concluded by giving some instances of urgent problems not yet solved in New Zealand, and stressed the point that only by continuous application by devoted bands of scientists could they hope to cope with these extremely difficult problems, which were of far more importance to every nation than people generally realised.

It is five years since Mr J. Thompson, who is in charge of the Chatham Islands school children on their visit to Christchurch, visited New Brighton. He attended the gala on Saturday and said that he was simply astonished at' the difference in the place. He had never thought it possible for the place to go ahead by such leaps and bounds, for only five years ago much of what now was closely, settled land was a barren waste of sand dunes.