1. Chaired a session on “Weed biology and ecology including impact on climate change”, in the 25th Asian Pacific Weed Science Conference at Hyderabad, India during 13th-16th October, 2015.
2. Chaired a session on Weed Invasives and Ecology in the 24th Asian Pacific Weed Science Conference at Bandung, Indonesia during 22nd – 25th October, 2013.
3. Chaired a plenary session on Agriculture Diversification, Climate Change, Management and Livelihoods in the 3rd International Agronomy Congress at IARI, Pusa Campus, New Delhi during 26th – 30th November, 2012.
4. Organized and chaired a session on Aquatic Weed control in the 6th International Weed Science Conference at Hangzhou, China during 17th – 23rd June, 2012.
5. Organized and chaired a session on Spotlight on Global Weeds at 5th International Weed Science Congress at Vancouver, Canada during 23rd – 27th June, 2008.
6. Chaired a session on Rice Allelopathy – Bioassay methods in FAO-Rice Allelopathy Seminar at China, 2007.
7. Chaired a session on invasive alien plants in Asia at NIAES International Symposium on “Evaluation and Effective Use of Environmental Resources for Sustainable Agriculture in Monsoon Asia” at Tsukuba, Japan during 12th – 15th December, 2006.
8. Chaired a session on “Herbicides” at the 20th Asian Pacific Weed Science Society conference at Ho Chi Minh city, Vietnam during 7th – 11th November, 2005.
9. Chaired session on “Ecology” at the 4th World Congress on Allelopathy at Charles Sturt University, New South Wales, Australia during 21st - 26th August 2005.
10.Chaired session at the national work shop on “Invasive alien species and biodiversity in India” sponsored by Ministry of Environment and Forest at the Banaras Hindu University, Varanasi during 18th - 20th August 2004.
1. Organized International Training Workshop on “Rice Technology Transfer Systems for Stress-Prone Environments in South Asia” at Department of Agronomy, Annamalai University during 29th April to 3rd May, 2013, in collaboration with IRRI, Philippines.
2. Organized FAO – Regional Training Workshop for Asia on Weed Risk Assessment, in collaboration with Food and Agriculture Organization of United Nations, Rome, during 25th to 28th September, 2007.
3. Feed The Future – Workshop on Climate Resilient Farming Systems for Food & Nutritional Security of Nepal, organized jointly with USAID – IKP at Annamalai University, during 8th – 9th, September, 2017.
1. Organized “National Seminar on Farming Systems (NSFS)”at at Department of Agronomy, Annamalai University during 19th March, 2013.
2. Organized National Seminar on Sustaining Food Supply, Agro-biodiversity and Rural Livelihoods at Department of Agronomy, Annamalai University during 18th and 19th February, 2010.
3. Organized International Biodiversity Day Workshop on Invasive Alien Species at Department of Agronomy, Annamalai University during 22nd May, 2009.
4. Organized National Seminar on Sustainability of Weed Control Options for the New Millennium, at Department of Agronomy, Annamalai University during 21st and 22nd December, 2000.
5. Organized VI Biennial Conference of Indian Society of Weed Science at Annamalai University during 09th – 10th Feb, 1995.