Invasive Alien Weeds (IAW) have become major threat to biodiversity and environment, besides reducing crop yields, and having adverse effects on human and animal health. Dr. RM Kathiresan, Professor of Agronomy, Annamalai University, TamilNadu, highlighted the invasive potential of IAW with respect to greater genetic variability, climatic adaptability, and biotic factors such as allelopathic potential and absence of natural enemies. He cited the examples of Prosopisjuliflora, Trianthemaportulacastrum, Echinochloacolona, Leptochloachinensis and Marsileaquadrifolia, and described how these weed species are tolerating climatic fluctuations and becoming invasive weed species.

He emphasized to focus more on studying the biology and ecology of IAWs. Since, herbicides are lethal to fish, other means of management of invasive aquatic weeds like water hyacinth using allelochemicals from Coleus ambonicus is suggested. There are some ‘sleeper weeds’ which are more dangerous under changing climate scenario. More emphasis need to be given on developing protocols for Weed Risk Analysis of alien invasive weeds of the country.

In addition to control, mass awareness programmes related to invasiveness and ill effects of these weeds need to be initiated to make the public and policy makers aware of the ill effects of these weeds. More than 140weed scientists attended this webinar, and there was a very fruitful discussion. From the interaction/discussion between the speaker and learned guests/participants, the following points emerged out: • There is a need to assess the area coverage under different IAWs in India under different Agro-ecological regions and their economic and environmental impacts. • There is a need to develop good publications on major IAWs. Few important IAWs need to be targeted with time. Some good projects on IAWs need to be submitted to ICAR/DST/DBT for financial assistance.