THE H.B. TRIBUNE WEDNESDAY, AUGUST 10, 1927 INSECT FRIENDS.

Hawke's Bay Tribune, Volume XVII, Issue 202, 10 August 1927, Page 4

THE H.B. TRIBUNE WEDNESDAY, AUGUST 10, 1927 INSECT FRIENDS.

fAUR latest London mail brings ” with it the announcement of the opening of a laboratory for the breeding of “beneficial parasites” at Farnham Royal, Buckinghamshire. This laboratory is under the direction of the Imperial Bureau of Entomology, and has been established by a grant from the Empire Marketing Board. The occasion was marked by an article written for the “Times” by Major Walter Elliott, M.P., who i B chairman of the Research Grants Committee of the Board, and what he had to say has a distinct interest for New Zealand, where we are trying to combat various “pests” by the introduction of insect enemies to them. At the outset he tells us that one-tenth of the world’s crops are raised by man only to be eaten by insects, and about one-fifth of all the crops of the tropics meet with that fate. The problem of controlling this tremendous wastage presents itself with special urgency to the British Empire. Nearly half of it lies within the tropics, while the Dominions, being largely agricultural, are in the front line of attack from the insect armies. “The toll taken of the crops,” says Major Elliott, “through lack of vigorous organised entomological enterprise cannot be calculated. But we can at least say that everyone who buys a loaf of bread, a joint of meat, a pound of fruit, a cotton shirt, or a rubber tire, is forced to contribute, however slightly, to the upkeep of the Empire’s insects. All these common articles of purchase are inevitably increased : n price by the wastage caused in their primary production by insect pests.”

Man himself is to a large extent responsible for this state of affairs. In preparing the hind for the growing of crops useful to himself he generally destroys a lot of native vegetation on which certain classes of insects that prey on others live. These die out,

leaving the field clear for those who can maintain themselves on the introduced crops. “For them,” as Major Elliott puts it, “a paradise has been created. They have nothing to do but eat and reproduce, and r e produce and eat, and to these processes they are now able to devote their absolutely undivided attention.” Secondly, wherever man has gone he has taken across the world with him, often by design, sometimes by accident, other forms of life hitherto as unknown as himself to the land of his adoption. He has started new plantations, orchards, and catt'eruns, and has let loose new insects and weeds, thus completely upsetting the balance of Nature. Australia and New Zealand provide the writer with a striking instance of this tendency, which has gone and is going on all over the Empire. Sheep, dairy and fruit farming now account for a major part of the wealth of these two Dominions. But we are apt to forget that before we came there were no sheep or cattle and no apple orchards or vineyards in all Australasia. The artificial emigration of economic plants and animals offers, indeed, -> fascinating study, but it has, unfortunately, a no less impressive reverse side. There were no apple orchards in Australia, before the European came, but neither wen; there any prickly pears. This single weed, covering 30 million acres of farmland in Queensland alone, was introduced within living memory, while here in New Zealand we know what blackberry has done for usInsect pests and weeds have thus also proved themselves bold and successful emigrants. Their danger to world economy lies in the fact that they are liable to arrive in new countries without the natural enemies that prey upon them in their original homes. They are given, moreover, o changing their diet. In Europe they may feed harmlessly upon some plant unimportant to agriculture; overseas they may prefer grain or fruit. Two mam lines of offensive have been launched against noxious insects. The first, which may conveniently be termed “chemical warfare,” falls outside the scope of Major Elliott’s article. The second, the method cf “biological control,” is the concern of the station now opened at Farnham Royal. The function of this “Parasite Zoo” is to discover, to breed, and to dispatch over the Empire the parasites which keep down the numbers of harmful insects. This is a nev departure for the British Empire, but the United States has several such laboratories, including eno in the South of France, and they have already obtained valuable results from them. In the field of agricultural entomological research the United States may claim to be well in advance of Britain, for, while its needs are much less considerable, it has hitherto spent annually more than four times as much as has the whole British Empire.

To our orchardists it will be of interest to learn that one of the first efforts of the new “Zoo” will be directed to discovering an effective parasite for the codling moth, while they, of course, know of the recent introduction of a parasite to deni with the earwig pest. We are possibly not yet troubled here with the lucerne flea, but in South Australia it is a very real enemy of the pastoralist. For it, too, and for the wooly aphis, the blow-fly—which in New South Wales is responsible each year for live stock losses valued at no less than two million sterling—the wheat, stem saw-fly, and the corn-borer destructive parasites are being sought. In some instances, of course, numerous parasites of a given insect are already known and it remains to be found by experiment which of them wil] prove most effective in th? oversea country for which they are intended. The parasite found after research to be appropriate may be as large as a wasp, but in most cases it is minute. The innumerable species and the microscopic size of these insects make their classification a prolonged business. Few entomologists have, moreover, specialised in them in the past, and there are therefore many species still awaiting the classification without which they cannot be useful to the practical agriculturist. It is the lack of trained men with the time and the equipment at their disposal for experiment and research that the “Zoo” is designed to bring to an end.