1052 PROCEEDINGS OF THE THIRD ENTOMOLOGICAL MEETING 



89.— NOTE ON PLANT IMPORTS INTO INDIA. 



By T. Bainbrigge Fletcher, R.N., F.L.S. F.E.S., F.Z.S., Imperial 

 Entomologist. 



(Plates 18 J— 182.)' 



Until about a year ago India was a free dumping-ground for the 

 plant-feeding pests of the whole world, and that we have not received 

 more of them' than we actually have done is probably only one more 

 example of the good luck attendant on the usual " muddle-through " 

 policy of the British Empire as a whole. Anybody was at liberty to 

 bring into India any living plants of any kind — fruit-trees, ornamental 

 plants, rubber-stumps, sugarcane-setts, etc.— and to bring with them 

 any insects which happened to be living on or in them, so that there 

 was every chance of our receiving, not only insects already known to 

 be bid pests in other countries but also the many insects which were 

 liable to develop into bad pests under novel conditions of climate, food 

 and absence of enemies which they found awaiting them in India. Here 

 we may remark that it is almost always the insects which have been 

 introduced into a new country that become the worst pests of that 

 country even in cases when they did, and still do, comparatively little 

 harm in the countries from which they were brought. In its own 

 country, in which it has lived for innumerable thousands of generations, 

 the numbers of any insect tend to remain constant on the whole, as 

 any undue increase is checked by natural causes of which parasites and 

 predators form a considerable proportion. But an insect introduced 

 into a new country providing sufficient food and a climate to its liking 

 is introduced, more frequently than not, without the parasites and 

 predators which' keep it in check in its old home, with the result that 

 it increases disproportionately and becomes a seripus pest. The same 

 tendency is of course true of animals other than insects and of plants. 



We in India know of at least three bad pests which have been intro- 

 duced of comparatively late years. One is Phthorimwa operculella 

 which was originally broughtinto Bombay about 1905 or 1906 with seed 

 potatoes from Italy and spread all along the Western Ghats and then 

 southward into Madras and northward into the Central and United Pro- 

 vinces and Bihar and which now causes damage amounting in the 

 aggregate to lakhs yearly. Another is Eriosoma (Schizoneura) lanigera 

 which has been brought into all the fruit-growing districts on imported 

 apple-trees and which has done serious damage already and is likely 

 to do more in the future as fruit-culture extends in India. Coccus 

 viridis is another example. These three insects have all become bad 

 pests in India and there is no doubt but that all were introduced. 



