WAR ON INSECTS

Rotorua Morning Post, Volume 2, Issue 595, 28 July 1933, Page 7

WAR ON INSECTS

d1sease carriers ENTOMOLOGISTS FIGH.T FOR THE BENEFIT OF MANKIND. e t GREAT PROGRESS MADE. ■ - For thonsands of years man has recognised the insects as things of beauty, of use or of menace. A drawing in an Egyptian tomb of about 2600 B.C. shows a man removing h'oney from a group of hives; engraved on a Minoan signet ring 3f about 1500 B.C. is a butterfly, symbolic of the soul, and the chryalis from which' it has emerged; while in Ekodus we read of the ravages of locusts which left "not any green thing . . . throughout all the land." Yet such are the vagaries of progress and civilisation that the Egyptians of to-day use a hive almost identical with the one nsed by their ancestors over 4000 years ago, and in England, in the 18th century A.D., a will was contested on the grounds of insanity because the testator possessed a collection of butterflies! In 1833, in a time of re-awakening interest in science, and a few months after Darwin started on his now famous voyage round the world, a few "gentlemen interested in the study of insects" formed a society for their mutual interest, and this Entomological Society of London, after a 100 years of steady growth in numbers and activity reoently celebrated its first centenary. Growth of Knowledge. In this 100 years, which has witnessed such unprecedented development in all branches of science, entomology has not lagged behind. When Wallace set out on his travels to the East Indies in 1854 he wrote in a sma.ll notebook particulars of the insects that were known from that area. To-day such particulars would fill a small encyclopedia. A hundred years ago there were scarcely any insects in our national collections; to-day entomology is a special department at the British Natural Museum and has about 8,000,000 specimens in its charge. Modern entomology has so many aspects that it is difficult for a student, and impossible for a layman, to keep abreast with its progress. It is often divided into so-called "Pure" and "Applied" Science, but there is no hard-and-fast dividing line and each side can help and learn from the other. "Pure" entomology now has its headquarters in the universities and museums of the world and among the amateurs. In their hands rapid progress has been made in the cataloguing a.nd classification of insect species, in the study of their life historics, their behaviour, hahits evolution and inheritance. But it is in the fields of Applied Entomology — medical, veterinary, agricultural and forest entomology and the control of insects damaging stored produce — that development has been so striking. Only 30 years ago, there was scarcely an official entomologist in the British Empire, and one man was Entomologist and Botanist to the whole of Canada, writes Dr. C. B. Williams, chief entomologist at the Rothamsted Experimental Station, in the News Chronicle. To-day there are 300 or more in the Government Dedepartments and experimental stations in England and in various colonies 'and dominions. And in other countries a similar development has taken place. Victories of Science. Sometimes a striking success comes their way. Thus malaria has sapped the energy of mankind for centnries and has even been considered as a contributory cause for the fall of the Greek and Roman Empires. The now familiar discovery of the part played by the mosquito in the transmission of the disease has helped to bring health and happiness to millions of hu. man heings. Sometimes chemical warfare is suc_ cessful against a pest, as in the use of poisons against leaf-eating caterpillars, but there is always the demand for newer, cheaper and more effective materials. Sometimes one insect can be played off against another, as in the case of the leaf-eating cocoa-nut pest in Fiji

which was recently practically exterminated in a few months by a deliber'ately introduced parasite. Heartened by these successes the small army of entomologists attacks the countless unsolved problems. Large areas in tropical Africa. are still beld hack in the development of their civilisation by the dreaded tsetse flies, which carry disease to horses, cattle and human heings. Recent reports from this front are more encouraging than for many years. The pink bollworm of cotton still destroys millions of pounds' worth of xrfaterial in almost every cotton-grow-ing country. The codling moth' still infests our apples, though much less so than formerly. I And every day new problems arise. New crops are grown and are attack,ed by unheard-of pests, or witth modern rapid transport across land and sea, old insects are carried into I new countries, where they may find j conditions ideal and develop into most j dangerous pests. Thus in the last 50 years America has received many of her most destructive pests from Europe, and still more recently the Colorado beetle has been carried across the Atlantic in the opposite direction and become established in the potato fields of France. Yellow Fever Menace. Yellow fever is at present confined to West Africa and tropical America, but the mosquito that transmits the disease is abundant throughout the East. It is difficult t0 ima.gine what might happen when transport across the Pacifie becomes so rapid that an undeveloped case of this terrible disease could reach Asia undetected and infect the mosquitoes of a new and crowded continent. The entomologist of to-day cannot work in isolation. He must call to his aid the doctor, the chemist, the botanist, the physiologist, the engineer, the agricultural expert, and indeed all the resourees of civilisation, in his fight against the insect pests. There is no panacea; over-enthusi-

asm for one method is as dangerous as laclc of enterprise: all methods must be put to the test. Nature has endowed the insects with almost unbelievable powers of rapid' multiplication and adaptability. Some even have developed a social life which in efficieney and complexity rivals our own. Against this man must oppose his reason and accumulated knowledge of centuries if he is to retain his supremacy on this earth and reap the full henefit of his labours.