Abstract

                                . It is well known that, due to the action and reaction of various factors in nature, there is maintained what is called 'a balance of life' in this world. One of the most potent inflü ences which helps to upset this even equilibrium, and bring about abnormal conditions in nature, is the part played by human agency. And, among the many such human activities, one has been the indis- criminate transportation of plants and animals from one country to another, without in the least realising or forseeing the disadvantages and the often disastrous results of many such introductions. We have some examples of how man, without any evil intention, has been responsible for bringing about a very undesirable state of affairs in different regions of the world, by thoughtless introductions of differ- ent forms of life from one region into another. Though the geogra phical position of India is more or less isolated, situated as she is. clearly separated by natural boundaries of mountain walls or seas from other regions, in these days of quick and easy transport facilities for all sorts of animal and vegetable products not only by land and sea but even by air, there is every likelihood of undesirable and harmful exotic forms, gaining admission into the country without our knowledge. This is the case particularly with insect pests and plants of different kinds. In this paper an attempt is made to survey the present position with regard to some of the important exotic plants and insect pests which are already with us or are likely to be intro- duced, pointing out the evil effects resulting thereby, and to offer some suggestions in the way of preventing such introductions as far as possible in the future.

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