Fight Against Pests

Sun (Auckland), Volume III, Issue 840, 7 December 1929, Page 10

Fight Against Pests

OUR PART IN WORLD CRUSADE

APPARENTLY from nowhere, a peculiar little insect has come to Auckland and voraciously attacked the blackberry, the most persistent and noxious of all plant pests m this country. ~ . , This insect is a welcome little stranger, for New Zealand, alone; with other countries in the world, is waging deadly war against insect and plant pests which in some places threaten man’s food supply.

There Is a long standing reward of a large amount awaiting anyone who can formulate a scheme for the complete elimination of blackberry. Nature, it seems, is suceeding where man has failed. This new enemy of blackberry was first reported a week ago from the Thames district, and later inquiry revealed the fact that it has been operating with telling effect upon these plants on the North Shore. Scientists at Cawthron Institute, Nelson, have been supplied with specimens and are now determining the family origin of the specie. In the meantime the fight against insect and plant pests is being relentlessly pursued. In New Zealand the problem is serious. In some overseas countries it has become almost a struggle for existence between man and insect. Science must determine ultimately who will win. New Zealand progress has not been altogether unaccompanied by the pests which are necessarily associated with civilisation. As one has been subdued by a parasitic recruit from overseas, another has sprung in its place—frequently as the direct result of introducing the parasite itself. Today there is a long list of unconquered enemies of natural development here, and hundreds of thousands of pounds of New Zealand money are spent annually in striving for their elimination. £400,000 A YEAR SAVED The ravages of the common blowliy perplexed sheepowners for many years, but, largely through the efforts of the Cawthron Institute, this has been successfully parasitised, and the industry saved at least £400,000 a year. The campaign against other pests has been assisted by armies of parasites brought at different times from overseas. The ladybird beetle —to which incidentally the new enemy of blackberry bears a striking resemblance —has been used in a very big way to clear blight and other visitations from fruit trees, and several consignments of these little workers have been sent to California where, in a climate much like New Zealand’s, they

are being used to attack fluted scale on fruit crops. The migration of pests is one of the most puzzling features of their observation. Any ship entering Auckland might have them in its cargo. Timber vessels sometimes bring them from Australia and America. A specie closely resembling the white ant was once found in a cargo of timber of the Commonwealth, with a consequent panic among local authorities who use poles and piles extensively. America and the Continent are leading the world in the crusade against insect pests, but this Dominion is annually taking a greater share in the work. An eminent scientist in the United States complains that the world is losing approximately 10 per cent, of all food raised because of the ravages of insects and plant pests. So voracious, indeed are the caterpillars of the gipsy moth —a particularly virulent pest—that a man with a similar appetite would require two or three tons of food a day! PESTS OF THE EARTH The earth is inhabited by about 120,000 species of beetle, and by winged pests, including flies, numbering many more than that —altogether about a quarter of a million kinds of insects for man to fight in his efforts to retain the food of the world for human consumption. Corn borers, the arch-enemy of the grain crops, have caused many hours of anxious thought, and many months of work in the laboratory. But the Ichneumon fly has lately been directed with unerring certainty against the borer, and the results are most gratifying to science. This fly lays its eggs through the tough layer of the coru stalk, and without exception marks the spot opposite busy borer. Presumably it can hear the borer at work inside the stalk. Some families of insect pests are more numerous than ever, in spite of years of incessant combat with science. All the resources of man, it appears, will be required to carry on the battle to success. If New Zealand has at last found the parasite for blackberry it will have taken a definite step toward this end.