Weed Science


Weed Science deals with weed biology, ecology and management, impact of herbicides on the environment, herbicide physiology and efficacy, and weed/crop/soil interactions. The Unit services programmes in the mother department and Faculty of Agriculture. It plays a critical role in M.Sc.Crop Protection. Some of the research undertaken by the Unit Include: management of Striga (witch weed) in maize,weed-crop interactions and weed management in vegetable crops and rice.

Career opportunities exist in agricultural research institution, agricultural firms, environmental firms, agricultural firms, agricultural extension service, agricultural and environmental consultancy services institutions, agrochemical firms, tertiary institutions and agribusiness.

Brief history

Weed science has been taught in the Department of Plant Science and Crop protection since the inception of B.Sc. Agriculture in 1970. The pioneer lecturers who taught weed science courses to undergraduate and Masters students included Prof. Ratemo W. Michieka who later became Chairman of the Department, first Vice-Chancellor of Jomo Kenyatta University of Agriculture and Technology (JKUAT) and founding Director General of the National Environmental Management Authority (NEMA). Dr. Safari Ariga joined the Department in 1988 as lecturer in weed science and has continued to provide this service over the years. The weed science thematic area has received a lot of support from leading weed scientists from the Kenya Agricultural Research Institute who have taught part-time and co-supervised postgraduate students.

Postgraduate training in weed science was offered under the M.Sc. and PhD Agronomy programs for over 20 years since the inception of the Faculty of Agriculture in 1970. A weed science course was taught to all agronomy students and students who were inclined towards weed science thesis research in this area. Prof. Safari Ariga who is a senior lecturer in the Department of Plant Science and Crop Protection is among weed science specialists who earned M.Sc. in Agronomy from the University of Nairobi. Academic staff in weed science thematic area were moved to Crop Protection Department following the split of the former Department of Crop Science into Crop Protection and Crop Science. Eventually, weed science thematic was fully integrated in M.Sc. Crop Protection which now produces weed science specialists.


Prof. Emmanuel Safary Ariga is an Agronomist/Weed Scientist and Food Security Consultant. He has PhD from International Institute of Tropical Agriculture (IITA, Nigeria) and University of Nairobi, Kenya (1996), MSc Agronomy/Weed Science, University of Nairobi, Kenya (1987) and BSc Agriculture, University of Nairobi, Kenya (1983). He has over 20 years experience in Agricultural Extension (Crops, Livestock, Irrigation, Soil and Water Conservation, Technology Transfer), Capacity Building, Research, Supervision and Consultancy. Much of this experience has been gained at the Ministry of Agriculture and Livestock, Kenya; International Institute of Tropical Agriculture (IITA), Nigeria; Tropical Institute of Community Health and Development in Africa (TICH), Kenya and University of Nairobi, Kenya. Prof. Ariga has extensive experience at both Institutional and Community, Levels in the following areas; Community Entry Process,read more

Prof. Emmanuel Safary Ariga, PhD(UoN) MSc (UoN) BSc(UoN)

michiProfessor Michieka is a member of staff at the University of Nairobi and has specialized in Agriculture (Weed Science) and Environmental Sciences. He obtained his BSc, MA, and PhD in Weed Science and Environment from Rutgers University, USA. He went for a Postdoctoral training at the International Institute of Tropical Agriculture (IITA) prior to his appointment at the University of Nairobi as a lecturer in 1980. He later became the Founding Vice Chancellor of the Jomo Kenyatta University of Agriculture and Technology where he served for 13 years.  Prof Michieka was later appointed the Director General of the National Environment Management Authority, NEMA, where he articulated the dangers of environmental pollution and natural resources degradation. He was responsible for the production of Kenya’s first report on the State of our Environment. Professor Michieka has done extensive research in Weed Science read more

Prof. Ratemo Michieka PhD(Rutgers)M.Sc. (Rutgers) B.Sc. (Rutgers)

maobeMr. Angwenyi Maobe holds Diploma in applied Biology from Mombasa Polytechnic, Higher Diploma from Kenya Polytechnic and BPHiL in Technology Industrial Biotechnology from Kenya Polytechnic University.Currently, Maobe is a senior technologist the department of plant science and crop protection University of Nairobi.




Mr. Angwenyi Maobe

nyagaSicily Wambui Nyaga/ Technologist, Department of Plant Science and Crop Protection, College of Agriculture and Veterinary Sciences, University of Nairobi, Kenya read more





Sicily Wambui Nyaga

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