Impact of Soil Borne Pests and Diseases on Root Architecture: Biotic-Abiotic Interactions Impacting Food Security in Southern Africa
Richard Sikora, University of Bonn
Abstract: The STIAS program on sustainable intensification of agricultural production and food security in Southern Africa is looking at technologies and processes that will lead to improved food production in small to medium size family farms in the semi-arid and dry sub-humid climatic zones that characterize this region. The poor yields obtained by farmers in Southern Africa are caused by low levels of fertility, soil degradation, lack of quality seed and insufficient plant protection. Yield is also greatly impacted by climate change induced hotter and drier soils. The STIAS program on sustainable intensification is looking for solutions to these problems and will be outlined.
Soil borne pests and diseases are present in all small scale farming systems in Africa. However, root health problems usually go unseen or are not recognized as serious constraints. These pests cause tap root deformation, tissue necrosis, stunting, abnormal branching and reduced biomass. Damage leads to abnormal root architecture and a decrease in the roots’ ability to function efficiently under the abiotic stress conditions existing in these climatic zones.
Attempts to improve crop yield on small family farms usually stress: breeding improved cultivars and to a lesser extent improving soil fertility management. Little to nothing is known about the presence and importance of soil borne pests that negatively alter root architecture. In most cases that are involved in synergistic interactions with abiotic stresses adding further to reduced plant growth.
If crop production is to be significantly improved upon in these climatic zones, crop management programs must include technologies that strengthen pest and disease management. Because genetic resistance to pests and diseases is often not available additional efforts needs to be placed on integrated crop health management approaches.
Breeding programs designed to select for higher yield need to be linked with selection of resistance/tolerance to soil borne pests and diseases. Bioassays designed to detect increased root biomass, root development and root depth penetration for improved water use-efficiency must be supplemented with tests for improved resistance/tolerance to soil borne pests and diseases. We need to look more closely at the impact of complex abiotic and biotic stresses on root architecture if yield and food security is to be improved in these climatic zones.
Bio: Richard A. Sikora is university professor emeritus and former head of the soil-ecosystem phytopathology department at the University of Bonn in Germany. He received his PhD in 1970 from the University of Illinois and began his international experience as a USAID-supported visiting assistant professor at G.B. Pant Agricultural University in India. As a faculty member at the University of Bonn, he has maintained an active research and teaching programme in soil pathology, nematology, soil microbiology, and biological control. He has been responsible for leading research on plant protection in the tropics and subtropics and has maintained an active international programme through student research and consultation having worked in over 30 countries on plant health management. Many of his over 150 post-graduate students have worked around the world and have become national leaders. His teams experience spans countries including: Kenya, Tanzania, Uganda, Malawi, Cameroon, Niger, South Africa, Thailand, the Philippines, Vietnam, Indonesia, India, Syria, Egypt, Costa Rica, Tonga, Central America, and Brazil. He has authored or co-authored nine books or proceedings, 30 book chapters, and two plant pathology handbooks, presented 28 invited papers at international meetings and published over 300 scientific papers. As consultant and board member of many international organisations and societies, he has provided invaluable leadership in international agriculture. He has also received numerous awards, including being selected as Distinguished Alumni of the University of Illinois, Fellows of two major Scientific Societies and for the International Service Award of the American Phytopathological society for his work in global plant health management. Richard was chairman of the CGIAR System wide program on Integrated Pest Management (IPM) and is presently convenor of the Stellenbosch Institute of Advanced Study (STIAS) think-tank dealing with the impact of sustainable intensification of agriculture on food security, the environment and human well-being in Southern Africa.
