INSECT MENACE

Greymouth Evening Star, 12 February 1936, Page 4

INSECT MENACE

MAN’S GREATEST ENEMY. SYDNEY, January 25. “Insects are probably man’s greatest enemy, .and there is ■ little doubt that if their ravages were not minimised the world would be faced with famine in a few years. Fires cost the United States less than £30,000,000 a year, but insects cause destruction of plant and animal products estimated at £400,000,000 annually,” said Mr. A. R. Woodhill, McCaughey Lecturer in Entomology, at the University yesterday. Mr. Woodhill said that the insect, ponulation was now greater than generally imagined, being about 60,000,000 to an acre of lucerne, and 3,000,000 to an acre of arable land in England. Their powers of proliferation wera greater than any of the larger animals. A single’" aphid could produce 1,037 individuals in 14 days, a queen termite 1,000,000 in a year, and thrips 64,000,000 in ten weeks. Numbers were kept down by enemies and, rigours of environment, but a prominent entomologist had esti-' mated that if there was no loss and every individual survived, the population of insects from a common leaf aphid would amount to 820,000,000 tons in a year.

Mr. Woodhill discussed means of combating pests. Mechanical traps, lieat, fumigants, and insecticides were useful, and 10,000 tons of locusts had been destroyed in a swarm in the Sudan in 1930. However, more permanent means existed in the encouragement of insect parasites and predators, and the control of farm practice; Manures increased the resistance of plants. Potash had made the tea plant immune from its enemy the tea bug.

In South Africa the grasshopper plagues have been controlled to some extent by killing the insects in their hopper stage on the permanent breeding grounds. Science Week ended at the University yesterday. Professor Macdonald Holmes discussed the use of the land, and said that migration was not altogether a political matter, but involved social questions. State control, and perhaps eventually even the rights of property. Also, some prominent geographers had revised their estimates of the population Australia could support, reducing the figures from as much as 150,000,000 to. about 30,000,000.

Professor Cotton traversed the methods used in measuring geological Lime: Professor Venwiller dealt with 1 liys'cs in its relation to philosophy, and Mi 1 . G. J. Burrows discussed complex salts and stereochemistry.