BIOLOGICAL CONTROL

Hawke's Bay Tribune, Volume XXIII, Issue 105, 15 April 1933, Page 4

BIOLOGICAL CONTROL

INSECTS AND WEEDS. WORK AT ROTHAMSTED. New Zealand would be consider ably worse off at present were it not for the research that has been conducted in England to find parasites to control our various weeds and insect pests. Blackberry, ragwort, gorse, white butterflies, aud other pests have all engaged the attention of Bothamsted Experimental Station, and Farnham Royal Institute, and tho debt that Now Zealand farmers owe to these aud. kindred research stations is considerable. The entomological department of Rothamstcd began its work for New Zealand in 1921 with the breeding of parasites for the control of certain insect pests in New Zealand, and later, after Dr. Imnis’s visit to Hawaii in 1925, it was extended at the suggestion of Dr. Tilyard, then the New Zealand entomologist, to the investigation of the possibility of controlling ragwort and gorse by insects. As always at Rothamstcd, the purpose was to obtain information on which action could bo based, and tho work consisted in making a detailed study of various possible insects so as to see which would be th ■ most likely to serve tho purpose. Having found this, the next step was to discover how to send supplies across to Now 'Zealand without too heavy a mortality. The steamship companies had no experience in carrying insects as cargo, and the necessary trials had to be made. Corresponding experiments were carried out in Now Zealand to see how to multiply up the stocks as soon as they were received. All this sounds very simple in the telling, but in point of fact it involved a good deal of work of a very specialised and highly skilled kind. As soon as it was shown that the method could be adopted in practice. The investigation had to be handed over to the laboratories at Farnham Royal, they having the facilities for the necessary large-scale work; it is common knowledge that their part of the work has been successfully accomplished, and that the insects are now supplied in ample quantities for New Zealand’s requirements. While there are good reasons to expect that the insects will keep the weeds in check, nt any rate to a considerable extent, it is by no means certain that their action will stop there and the New Zealand experts arc fully alive to the possibility that some day action may have to be taken against the insects themselves, beneficent though they may bo at the moment. This problem is at yet remote, and we hope it always will be. It affects not only New Zealand, but all other countries where use is made of biological control. The entomological department at Rothamstcd is therefore pursuing the study of methods whereby these and other insects may themselves be controlled whenever the need arises, and as the first stage in this investigation Dr. Williams is studying the factors that make for increases and decreases in insect populations. The purpose is the same ns for all the Rothamstcd investigations—to gain knowledge and to put it into such form that it can be used by experts elsewhere: then to pass it on to those who are in the best position to make tho large-scale applications.

BLEND OF SCIENCE AND BUSINESS. Writing in “To-day and Yesterday,” Sir Stephen Tallents, of the Empire Marketing Board says: — “If I were challenged to pick out from the texture of present-day England one of tho persisting threads which to-day eludes public attention, 1 should fasten on the silent growth in our midst of scientific agricultural research. Agriculture is a fascinating blend of an art, of science and of a variety of businesses, upon which our daily life literally depends. Yet if to some of us the name of Rothamsted may by now have come to wear a special meaning, how many of us could tell what is tho modern significance of such good English and Welsh placenames of East Mailing or Aberystwyth, Long Ashton, Princes Risborough or Farnham Royal? Even if wo could identify their importance in the Great Britain of to-day, we should be unlikely to find a similar significance in the less familiar names of Onderstepoort or Palmerston North or Amani. Yet each of these places harbours its own group of scientific workers, remote from political issues, yet devoted to a public cause. They are studying, these modern guilds, the problems which affect man’s growing and control and safeguarding of the fruits of the earth. Their work deserves to be known in our own times alike for its intrinsic value and its supreme interest. ‘‘ A man sits in the Imperial InInstitute of Entomology at South Kensington, charting on maps and in card indexes information about locust movements and locust ways, as it comes to his table from some Hi British and 25 foreign countries. A third of the land ureii of the world is subject to locust invasion, and so has been for centuries. Where the locust swarms pass, every blado of herbage is destroyed. Wo read the other day of a farmer in Kenya who saw 90 acres of maize destroyed before bis eyes in 20 minutes. It has been officially estimated that the present wave of locust invasion has cost in the last Jive years at least £7,000,000 and 28,(100,000 days of human labour. Hitherto throughout history wen have confined themselves to meeting tho plague when it arrived. In the desert of Sinai, for example, not long since, tin army of men 1000 strong was reported with six-wheel lorries, camels and flame guns, feverishly digging trenelies bi tHe line of « locust invasion. The infiectt late tk»

trenches ‘in a continuous greenishyellow cascade,’ and every 10 minutes the trenches, a mile in length, were swept with petrol flame. Two years ago certain countries of the Empire combined to create in that South Kensington room a locust intelligence headquarters, which the Governments of Franco and Italy have since recognised as un international centre. Two observers based on that centre are actively at work in Africa. For the first time in history an attempt is being made to forecast locust invasions and to trace their vulnerable points in the breeding places from which they start.’’