Biological invasions by non-native (exotic) species constitute one of the major threats to environment and biodiversity including forestry, livestock and agro-ecosystem. Invasions by alien species cause an imbalance in native ecosystems and many of them cause considerable economic loss in the initial phase of entry. Such invasive species are likely to breed profusely in the absence of natural enemies in the newly found environment and cause biotic upsets, out-competing native species. Biological invasions, through the routine importation (both accidental and deliberate) of harmful non-native organisms occur frequently, and are estimated to cost more than $100 billion per year world-wide. Nearly 25% economic losses due to bio-invasions are attributed to invasive weeds, pests and diseases. Invasive species are second only to habitat destruction as the major cause of biodiversity loss. In the globalized era, goods and services produced in one part of the world are increasingly available in other parts of the world and people around the globe are more connected to each other than ever before paving the way for accidental introduction of invasive pests.