CO885-(19-20) — Page 346

PUBLIC RECORD OFFICE

Reference :-

C.O. 885

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in the cultivation of tropical products, the discovery of the part played by insects in disseminating human disease, have brought entomology to the front, and have shown that, far from being a science concerned solely with the minute classification of interminable varieties and species, it is a science which has a great significance for man, and one which requires to be developed in serious earnest if we are to be in a position to harvest our crops, to cope with disease, and to populate tropical areas successfully. In closely cultivated countries with temperate climates, insects have not the significance that they have in tropical countries and in newly-planted areas, and it is perhaps due to this that in the study of economic entomology England is somewhat behind America and some other nations.

Out of all the hundreds of thousands of kinds of insects which now live on the earth, a small proportion are of very vital importance to man, affecting his agricul ture, his cattle, his merchandise, and causing or transmitting disease to man on a very large scale. It is these with which we are now concerned, and it is on their account that the economic entomologist comes to play so vital a párt at the present day.

All plants, whether crop plants or wild plants, are affected by insects, which live on them, destroy them, lessen the value of their produce, and increase at their expense. In nature, this is limited and checked; but in cultivated crops, grown in blocks, under artificial 'conditions, these insects become abundant, increase beyond nature's due proportion, and take a very perceptible part of the crop.

It is not only as agents of destruction that insects have a great economic significance; large industries depend directly upon insect activities, and the useful insects are no small item in man's economy. Bees. offer the most familiar example; the production of beeswax and honey is dependent upon a very few species of domesticated bee, which man has exploited and whose products have been obtainable in no other way. This is now a profitable industry to many thousands of beekeepers in practically every country, and the production of honey and wax is now carried on on a very large scale.

Silk is another very large insect industry, which has existed for centuries, but which has, in the last century, benefited enormously from the application of scientific study. Silk is produced mainly by one species, formerly wild, now domesticated, and also by a few wild species and some minor domesticated ones; the study of these insects by entomologists has had, and is having, remarkable results in the industry, and the production of silk is one of the big industries of the world which might be very much extended in the British Empire; the total production of the chief grade of silk, raw silk, is about forty million pounds annually, worth about twenty million pounds sterling, and there is also the waste silk, tussore, shartung, eri, and other kinds, totalling probably as much again.

Another industry which is less familiar is the shellac industry; lac is the resinous covering produced by a few species of scale insects living on trees in India. Burmah, and Malayia; the value of the production in India and Burmah exceeds three million pounds sterling annually, and no substitute for this insect product is as yet known. Scientific entomology is only now beginning to be applied to this insect, but there is a large field for research and improvement, and some progress has been made. Other minor insect industries there are also; the cochineal insect in dyeing, the blister beetles in medicine, the various insects used as food are examples, and there is a considerable trade in insects used as food for birds.

Nor is it certain that there are not great possibilities in the future; while science has to a large extent exploited the plant world for commercial products, little has been done systematically with insects, and while there are important insect industries in India, other tropical areas may have unexploited possibilities, which the future will bring forward. The subject is so new, so little investigated, that it is impossible to say what products the systematic investigation of tropical fauna may bring out. There is here a large field for research and inquiry, and one in which England, with the vast tropical areas she is colonising and opening up, is particularly interested.

It is, however, from the destructive side that insects are of the greatest significance to man, and though the results of practical entomology are in a sense indirect they are of very great commercial importance. Cotton is a crop in which commerce is at present very deeply concerned and whose production in the Empire is being extended; in this crop destructive insects play a very great part; it is probable that were there no boll worms, no cotton stainers, no cotton caterpillars, the gross yield of cotton from the area now existing would, without further effort on man's

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part, be increased ten to twenty per cent.; in Sind and the Punjab in one year the cotton crop failed wholly from the attack of the boll worm; the loss in cotton not produced was in excess of £2,000,000 sterling, and this was due solely to the work of one cotton pest. The same applies very markedly to cotton which is introduced into new localities or to new varieties introduced in new areas; the first trials of Egyptian cotton in many parts of India failed wholly from the unforeseen attacks of the pink boll worm; in the trials made of tree cottons in many countries it has been found that the pests are the factor determining success or failure. neglected it is commercially impossible to grow tree cottons in India at the present If the pests are time, and for want of realising this much money has been wasted; in every cotton- growing country insect pests are of the first importance, and no one growing cotton in any part of the world can afford to neglect them.

The same may be said of very many crops; every crop has its pests, and we have to deal with them efficiently if we are to cultivate crops as commercially successful undertakings. The pests may be virulent special ones, such as the woolly aphis of the apple, the phylloxera of the vine, the destructive moth of the potato; these limit themselves to special crops and, if not treated, the industries concerned are ruined. Or the pests may be general ones, such as locusts and swarming caterpillars, which attack almost all crops and which devastate large areas, appearing every few years in great abundance and doing great damage. In all countries crop pests are known, more so in the tropics and in countries where very large areas are given up to growing a few crops, as in the wheat areas of Canada, the cotton areas of the United States, Egypt, and India, the rice areas of India. In England the conditions of agriculture and climate, the dense cultivation, the high standard of cultivation, and the availability of scientific resources make such large attacks impossible, and we cannot quote striking cases, though the aggregate damage done to crops is still large; but in other countries, notably in the tropics, these attacks reduce the crops over very large areas, making systematic campaigns, carried on with all the available resources of Government, a necessity. In the Bombay locust outbreak of 1903-4 we spent £14,000 in fighting the pest; in Massachusetts on the gipsy moth campaigns as much as £20,000 to £40,000 were spent annually in checking the pest; and similar sums are spent and are well spent-in similar campaigns in other countries. These sums are only a proportion of the loss these countries would otherwise sustain were these pests not checked, and we are not able to estimate the gross losses sustained by agriculturists throughout the world. A recent report puts the loss sustained in the United States from the pear thrips, a minor pest, at one million dollars annually, and in the United States, where the organisation of entomology renders figures available, the total loss from destructive insects is put at three hundred million dollars annually. In British India, the losses to the eight principal crops at a con- servative figure amount to fifteen million pounds per annum, and to the country as a whole, in all crops, amount to well over double that amount.

Were these losses unpreventable, these figures would be of no value, but very largely the losses are preventable, either by the individual action of farmers them- selves or by collective action on the part of the people, aided by Government. What- ever this action is, it must be founded on and guided by scientific entomology, i.e., ol an accurate knowledge of the lives and ways of the insects causing the losses. Year by year the successes of entomology grow greater; a notable case is the success of the collective action of the South African Colonies against their locusts; the migratory locusts of North India and the Bombay locust are now fought successfully; the potato moth, which in India and Australia did so much damage, has been checked by simple means within the reach of the cultivator; the phylloxera of the vine and the woolly aphis of the apple have been met by the introduction of resistant stocks on which the pests will not live; and if there are many cases where remedies or preventives are as yet beyond the reach of the farmer or where no profitable remedy has been dis covered, there are far more cases where remedies or preventives are applied with profit and success.

I will quote a case where we have definite figures: In 1905 the cotton crop failed over 700,000 acres in the Punjab; eight districts reported no yield at all, four reported a quarter crop, and one a crop a trifle over a half; in 1906 we adopted three remedies, impressing them on the cultivators with all the resources of Government but not actually spending any large sums of money; one remedy was a failure, two were Successful. In 1906 the districts that had no yield in 1905 reported an average of 53 per cent., those with a quarter yield reported 62 per cent., and a loss of two and a half million pounds sterling was reduced to one of only seven hundred thousand