Invasive noxious weed management research in India with special reference to Cyperus rotundus, Eichhornia crassipes and Lantana camara

Abstract

Weeds are eternal pest causing substantial losses of crop yields and quality, which are directly related to food security and safety, respectively. With existing crop protection measures, approximately one-third yield losses occur globally due to weeds, in which contribution of invasive/ noxious weeds is enormous. Invasive/noxious weeds have become a challenge in developing Asian countries, especially in India. These invasive/noxious weeds are widely distributed in all kinds of ecosystems. Invasive species cause losses of native biodiversity including species extinctions, and changes in hydrology and ecosystem function. The total annual cost of dealing with invasive species worldwide is estimated to be in the hundreds of billions of dollars, including costs of control, detrimental effects on human health and losses in agricultural production and ecosystem services. An estimated 20-30% of all introduced species worldwide cause a problem in a way or the other. The list of invasive alien weed species for India is well documented and available in public domain. There are 173 invasive alien species documented in India belonging to 117 genera and 44 families, which represents 1% of the total Indian flora. Tropical American region contributes to the maximum number (with 128 species or 74%) followed by tropical Africa (11%). Other regions, which contribute marginally, are Afghanistan, Australia, Brazil, East Indies, Europe, Madagascar, Mascarene Islands, Mediterranean, Mexico, Peru, Temperate South America, Tropical West Asia, West Indies and Western Europe. Different weed management practices are used for controlling these weeds both in cropped and non-cropped situations. Among these options, none is enough to completely control these weeds. Thus, integration of all these weed management tools is needed to be done. Considering the extent of yield losses caused by these noxious weeds, a comprehensive, effective and well adoptable technology is urgently needed to overcome these challenges. This review article is based upon the most striking management approach for the noxious weeds. It also emphasizes the relevance of future research aspects, such as early detection tool by adopting satellite based remote sensing, application of biotechnological tools like development of herbicide resistant crops, development of new herbicides molecules, enforcement of strong legislation and research on alternate approaches like weeds use for industry (making paper, herbal medicine and bio-fuel) to ensure higher income and livelihood security of farmers.