ENTOMOLOGICAL SCIENCE

Otago Daily Times, Issue 22022, 3 August 1933, Page 11

ENTOMOLOGICAL SCIENCE

ITS SERVICE TO MANKIND LECTURE BY DR D. MILLER In the Y.M.C.A. Hall last evening a large audience had the privilege of hearing a lecture entitled “Entomological Science in the Service of Mankind,” delivered by Dr David Miller, chief of the entomological department of the Cawthron Institute. The lecturer dealt with his subject lucidly, and in language that was entirely free from technicalities, and his review of the work being done by entomologists with a view to controlling the insect pests of the world was listened to with keen interest. The address was delivered under the auspices of the Otago Provincial Council of the New Zealand Farmers’ Union, the Otago Institute, and the Dunedin Chamber of Commerce. , The chair was occupied by Professor Benham, who briefly introduced Dr Miller, and, after expressing pleasure at being asked to preside at an address given by a former pupil and congratulated the secretary or the Otago branch of the Farmers’ Union (Mr A. C. Cameron) on haying arranged for Dr Miller to give a series of lectures throughout the province on matters that vitally affected primary producers. For the purpose of coping with the control of insects and diseases detrimental to plants and animals, said Dr Miller, research had. in recent years, become organised on a vast scale throughout the world in institutions either connected with or independent of Governments and universities. In regard to biological problems influencing agriculture and, to a certain extent public health, the institutions dealing with insects were most numerous. This was better realised when it was considered that of all animal species insects comprised about 80 per cent., and amongst this host many devoured vegetation valuable to man, while others spread diseases fatal to man and his domestic animals. On the other hand, comparatively few insects, _ with the exception of bees and parasitic forms preying on destructive ones, were of value to civilisation, which was dependent upon the smaller groups of animals tor its beasts of burden and as a source ot food and clothing.

RESEARCH ORGANISATIONS. If one reviewed the entomological research stations of the world as a whole one found that the Urn ted States o! America took the lead with ‘ts 'ast Federal and State institutions followed by the British Empire, France Russia, Geimanv Italy, and Japan, while many European States as well as Egypt and several South American States had developed important institutions on . a lesser scale. Within the British Empire, there nas a central organisation in London the im pen.il Institute of Entomology-will which co-operated the Lmpire chain of entomological research stationsi situMx-d in the West Indies, Canada, hD I - wT Zealand. Australia, the East Indies, Indn . and Africa. For the purpose of can in it out special research on behalf of and supplying parasites to the whole Empu the Imperial Institute of Entomology had established at Farnham Royal, near \\ ndsor a special laboratory, and this had proved of incalculable value to New Zealand, which, despite its size, had absorbed more than half the output of the laboratory, the shipments of parasites sent to the Dominion in 1931 alone totalling no fewer than 260,000 insects. THE TOLL OF THE INSECT.

Dr Miller went on to say that the opinion was now generally accepted that 10 per cent, of the world’s agricultural products were destroyed annually by insects, and in order to secure some idea of the magnitude of the problem that faced entomologists it was of interest to compare the position in the British .Umpire with that in the United States ot America. Within the Empire losses had been computed by the Imperial Institute of Entomology at £0.000.000,000, representing the labour of 45.000.000 men, and in the United States of America at £200.000,000, or the livelihood of 1,000.000 men. On the other hand, the total revenue of the Empire might be taken at £1,400,000,000. and of the United States of America at £800,000,000, while the expenditure on entomological research was £SOO 000, or .0357 per cent., and £2,000,000, or 25 per cent, of the revenue, respectively. It was to he noted, therefore, that the British Empire lagged far behind in tiie mattei* of entomological research. In view of the Empire’s enormous annual losses, much of which, it _ was known, could lie definitely saved, this unbalanced state of. a flairs was all the more striking ami, indeed, returns from the result of one investigation in one small group of islands within the Empire annually c?qiinllcd four times the nuium! expend!* ture for the whole Kinpirc. “AN OUNCE OF PREVENTION.”

It was unfortunate, continued Dr Miller, that no effective steps were taken lo protect the Dominion from the many scourges that could be brought to its shores. A most spectacular example of this was the cabbage white butterfly. This insect' wa 8 lirst found at Napier in 102!), and was reported in 1930, from which time it rapidly spread through the North Island, To-day, it was a conspicuous feature of the countryside, but it there had been an efficient quarantine service this insect would never have had a chance to establish itself, and even if it had escaped notice until it was first established in Napier, it could, had the proper measures been taken, have been stamped out. The Government Entomologist (Mr Muggeridge) was now establish: ing parasites against the pest, and it was hoped that the control would be equally ns spectacular as was the spread of the insect. The destructive potentialities oi the butterfly wore enormous, as could be seen where cabbages and other related plants had been stripped of leaves. The food range of the insect was wide, and included cruciferous plants, and if extensive attacks were made on the turnip and rape crops of the Dominion, then the situation would bo extremely serious, especially in regard to the dairying and sheep industries. The question of adequate quarantine and inspection service in New Zealand was a matter for immediate attention. The control of injurious insects that had become well established

aimed at reduction, not extermination, which could be effected only on rare occasions. If one surveyed the campaigns carried on in recent years against destructive insects throughout the world one could npt but be impressed by the fact that, in spite of the many problems which had yet defied solution, the resultant oenefits to mankind were beyond assessment. Whole territories had been freed of disease-carrying insects, with consequent benefit to man, his domestic animals, and his crops. INSECT-BORNE DISEASES.

Dr Miller went on to deal with insectborne diseases of various kinds, and referred especially to diseases caused by ticks, one of which —Texas fever —had seriously threatened the cattle industry of the United States of America. A study of the tick’s biology evolved a method of control, and by means of this the cattle industry of the southern States of the union was saved from extinction. Another tick-borne disease in North America was Rocky Mountain spotted fever, and important advances in the development ol parasites against the tick had been made. It was intended to establish these parasites against the cattle-tick in New Zealand. Fortunately there were no diseasecarrying mosquitoes in New Zealand, but in the tropics, entomological research had been responsible for ridding vast areas not only from mosquitoes but from disease also. Similarly with the dreaded “ sleeping sickness,” which had brought death to countless thousands of human beings and domestic animals, a campaign for the control of the tse-tse fly had been launched, and this had proved successful in many areas infected by the fly. AGRICULTURAL PESTS.

Touching on the control of agricultural pests, Dr Miller said that one of the outstanding factors inhibiting the production of apples in the Dominion was for many years the woolly aphis; and there were few orchards that were not infected by this insect. A few years ago Dr R. J. Tillyard introduced from North America the Aphelinus parasite, which rapidly gained a spectacular victory over the woolly aphis, with the result that thousands of pounds were annually saved to orchardists. The grass-grub and the earwig were other problems to which the entomologist had given particular attention, and it was hoped that research in this direction would bring about control of these pests. A remarkable instance of science coming to the aid of the agriculturist was the arresting, in Fiji, of the ravages of the Levuana moth. This insect in 1925 became epidemic, with the result that in a very short time large areas of coconuts were completely ruined. Parasites from the Federated Malay States were introduced and liberated, and within three months the Levuana moth was completely under control. The cost of securing the parasite was £3500, and its introduction assured revenue of approximately £1,000,000 per annum to the colony, ■ . Methods of dealing with insect pests in other countries such as the Mediterranean fruit fly, the grape-vine louse (which was responsible, in 1884, for such havoc among the vineyards of France) and mulberry scale, were explained bv the lecturer, who also gave a summary of the steps taken by entomologists to control insects which prey on forest trees, and of the research into the possibilities of utilising parasites for the control of weeds. In this connection he dealt particularly with the introduction pf parasite insects to assist in eradicating such noxious weeds as piri-piri, gorse, ragwort, and blackberry. In conclusion, said Dr Miller, entomology was by no means a hobby; it was a very serious business, the returns from which were very far-reaching in the interests of science. It was one of the vastest insurance organisations for national safety, from which the profits accruing to the policy-holders far exceeded all human assessment; it was an insurance organisation supported by premiums that would bring many a life insurance society, into bankruptcy. On the motion of Mr M. A. Kinney, president of the Otago Provincial Council of the New Zealand Farmers’ Union, Dr Miller was accorded a hearty vote of thanks.

The lecture was illustrated by a series of very fine lantern slides, the lantern being operated by Mr A. C. Cameron.