NA TURE 



169 



THURSDAY, JUNE 23, 1887. 



THE AGRICULTURAL PESTS OF INDIA. 

 The Agricultural Pests of India and of Eastern and 

 Southern Asia, Vegetable and Animal, Injurious to 

 Man and his Products. By Surgeon-General Edward 

 Balfour, Author of " The Cyclopaedia of India," &c. 

 (London : Bernard Quaritch, 1887.) 

 r~^ ONSIDERABLE attention has been directed lately 

 V y to agricultural pests of all kinds, and especially 

 to insect pests, in various countries, because the injuries 

 occasioned to crops by their agency have greatly 

 increased, and in some instances altogether new dis- 

 orders and diseases attributable to them have appeared. 

 The universal international exchange of agricultural 

 produce and other commodities has tended and must 

 tend to distribute insects, fungi, and other sources 

 of evil to mankind, animals, and plants, throughout 

 the world. Thus the terrible scourge of the vine, 

 the Phylloxera vastatrix, was first introduced into 

 the French vineyards with plants, or cuttings, of vines 

 imported from the United States. Very many insects 

 most noxious to agricultural, fruit, and garden crops, in 

 the United States were brought there with plants, cuttings, 

 fruits, and seeds. The elm-leaf beetle, Galeruca xantho- 

 melcema, which is now seriously damaging elm-trees, was 

 not known in the United States until 1837, and came 

 probably from France, or Germany, where it had been 

 a troublesome pest long before that date. The hop 

 fly, Aphis huinuli, called the " barometer of poverty " 

 by a Kentish historian of hop culture, has only re- 

 cently visited the hop plantations of America ; yet it 

 caused almost a total blight last year in those of the 

 Eastern States, upon an area of nearly 40,000 acres. 

 Without any doubt this insect was conveyed from England 

 in " hop-sets." The Hessian fly has been conveyed 

 to Great Britain by some means or other not yet dis- 

 covered, during the last year, and bids fair to be a 

 dangerous and permanent scourge to the wheat and oat 

 crops of this country. 



It is the same with moulds, or mildews, or " blights," 

 occasioned by fungi. The vine mildew, Oidium tuckerii, 

 was not dreamed of in France until 1845. The potato 

 mould, Peronospora infestans, had shown no important 

 sign in Great Britain until 1844. The coffee mildew, 

 Hentileia vastatrix, did no serious harm in the coffee 

 plantations of Ceylon until after 1870; but during the last 

 ten years it has enormously decreased their yield. 



Diseases of animals have also been greatly intensified 

 during the past thirty years in Great Britain and in 

 other countries. In India, as we gather from this 

 little book of Surgeon-General Balfour, anthrax, pleuro- 

 pneumonia, rinderpest, foot-and-mouth disease, are so 

 rampant that the Madras Government has recently 

 appointed an inspector of cattle diseases with a sufficient 

 staff under him. 



There is no doubt that the attacks of certain insects 

 and parasitic fungi are more frequent and more fatal 

 than formerly. Hop blights from aphides and mildew, 

 Sparotheca castagnei, are far more common and destruc- 

 tive in England than they were fifty years back ; and 

 Vol. XXXVI.— No. 921. 



the orange-growers of Florida, California, and other 

 places where oranges are cultivated, are at their wits' 

 end to combat the ravages of, scale insects, Coccidae, 

 which have greatly increased since 1870. 



It is a moot point as to whether this is due, or not, to 

 modern and more artificial systems of cultivation, which 

 may be more favourable to the spread of insects and 

 parasitic fungi. Or it may be that these new systems 

 interfere with the balance of Nature by decreasing 

 parasitic and other insects, and birds and other animals, 

 which are the natural foes of injurious insects. It has 

 been discovered by Prof. Forbes, of Illinois, that several 

 species of the Carabidic and Coccinellidae eat the spores 

 of fungi ; therefore an unusual increase in the number of 

 birds, or other foes of these insects, might occasion a 

 serious spread of mildews. 



The importance of the subject of agricultural pests 

 cannot be overrated. It is now fully recognized by the 

 Governmentof the United States, who have a distinguished 

 entomologist upon the staff of the National Agricultural 

 Department. Besides this, many of the States have their 

 own entomologists, who furnish frequent and valuable 

 reports and advice as to methods of treatment. In 

 England the Agricultural Department of the Privy Council 

 have lately issued a series of reports upon insects in- 

 jurious to crops, written by Mr. Charles Whitehead ; and 

 Miss Ormerod, the entomologist of the Royal Agricultural 

 Society, has published annual reports for upwards of 

 ten years, which have been of the utmost value and 

 practical benefit to agriculturists. And in India, as 

 Surgeon-General Balfour tells us in this work, the serious 

 injuries caused by insects and other animals, fungi, and 

 bacilli, to mankind, animals, and plants, have at last 

 attracted the attention of the Government of India, and 

 it is proposed to invite communications from those engaged 

 in agriculture, forestry, and horticulture in that country, 

 to furnish matter for periodical reports like those issued 

 from time to time by Miss Ormerod. These would of 

 course be published in the vernacular, and should be illus- 

 trated by woodcuts, as Miss Ormerod suggests in her com- 

 prehensive letter in the preface of "Agricultural Pests 

 of India." It is much to be hoped that a competent 

 entomologist may be appointed in India to direct this 

 work. 



Surgeon- General Balfour, so far back as 1880, recom- 

 mended the Secretary of State for India to obtain reports 

 on the diseases of cattle and plants, and on creatures 

 noxious to mankind and vegetation. In his admirable 

 " Cyclopaedia of India and of Eastern and Southern 

 Asia," published in 1885, he gave a general view of the 

 entomology of these regions, and described the losses 

 sustained by agriculturists from these and similar causes. 

 He has followed this up with the work now under review. 



Though a small book, the " Agricultural Pests of India '' 

 is very ambitious in design, as it treats not only of insects 

 and fungi and animals injurious to mankind and agri- 

 cultural crops, but of all manner of birds, beasts, and 

 fishes. Several of these cannot, even by the greatest 

 stretch of the imagination, be classified as pests to 

 agriculture, and seem to be altogether out of place in 

 this category. Under the heading "Fish," sharks and 

 siluroids are described, though it is not by any means 

 clear in what way they are agricultural pests, except, 



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