Document(s) 9 of 14

Introduction 

A team of scientists funded by IDRC has found a promising way to control the noxious weed. Researchers at McGill University have discovered a fungus (Fusarium oxysporum) in the soil in Mali which can suppress the weed's growth. In a pilot study, the fungus was grown on sorghum straw then spread on farmers' fields at sowing time. Not toxic to humans, the fungus attacks Striga at an early growth stage resulting in dramatically increased sorghum yields. This technique is being tested further under field conditions in Mali in collaboration with Mali's Institut d'Economie Rurale (IER) and the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT).  

Striga spreads rapidly in areas of low soil fertility and decreasing plant diversity, conditions often experienced by poor farmers in dryland zones. The African countries most affected are Burkina Faso, Cameroon, Mali, Nigeria, Sudan, and Togo. Should this approach to controlling Striga eventually be adopted by African farmers, it would complement concerted efforts to replenish declining soil fertility.  

Future outlook and potential impact 

• Striga-infested fields of sorghum treated with the fungus have shown a 75-90% reduction in Striga infestations and yield increases of up to 100%.


• The fungus, which prevents the spread of Striga, can be grown on sorghum
  straw which is inexpensive and readily available in Africa. This means the
  fungus could potentially be "produced" by village cottage industries for local
  use (see Supplemental information below). 


• The fungus is now being tested on farmers' fields to evaluate its effectiveness under different climate and soil conditions. Researchers hope to disseminate this approach in other regions by early 1999 so that more widespread and effective control of Striga can be achieved.
• Use of this fungus to control Striga could dramatically increase cereal crop yields in sub-Saharan Africa, where almost 530 million people depend directly on the land for their living. This would potentially increase incomes, food security, and nutrition in a continent where food production has not kept pace with rapid population growth. 
• Use of the fungus could reduce the demand for imported chemical herbicides, which pose a threat to the environment and human health. 
• This project could ultimately reduce losses caused by Striga infestations in Africa, estimated at US $7 billion annually. 

Prerequisites

Potential users 

Contact 

Marie Ciotola, Research Consultant  
McGill Biopesticide Research Laborator  
McGill University  
Ste-Anne-de-Bellevue, Quebec,CANADA H9X 3V9 
Tel: (514) 398-7851, ext. 8746 
Fax: (514) 398-7897 
E-mail: cyk6@musica.mcgill.ca  

Don Peden, Program Officer  
International Development Research Centre  
P.O. Box 8500,  
Ottawa, Ontario, CANADA  K1G 3H9 
Tel: (613) 23-6163, ext. 2449 
Fax: (613) 567-7749 
E-mail: dpeden@idrc.ca  

Resources and publications 

Ciotola, M.; Hallett, S.G.; Watson, A.K. 1996. Impact of Fusarium oxysporum isolate M12-4A, upon seed germination of Striga hermonthica in vitro. Sixth International Parasitic Weed Symposium, pp. 871-875. Moreno, M.T., Cubero, J.I.; Berner D.; Joel, D.; Musselman, L.J.; Parker, C., eds. April 16-18, 1996, Cordoba, Spain. 

Savard M.; Miller, J.D.; Ciotola, M.; Watson, A.K. 1997. Production of metabolites by a strain of Fusarium oxysporum used for Striga control in west Africa. Biocontrol Science and Technology (in press). 

Fungus Fights Cereal Killer in Africa, IDRC Reports  

Kenya: Sebastian fallows for striga weed control?  

Ker, Andrew. Farming Systems in the African Savanna: A continent in crisis. IDRC Books.  

Profile: Joseph Oryokot, crop scientists at the Serere Agricultural and Animal Production Research Institute (SAARI)  

Weeds, Weed Control and Management, ICRISAT  
 

Supplemental information 

Because this approach would prove too time-consuming for farmers, researchers are now developing an effective way to produce a dry version of the fungus that can be mixed with unsterilized straw and applied by farmers at sowing time. This will be field tested for the first time in 1997. Ongoing research will also explore ways to prolong the shelf life of the inoculum and simplify its application. The hope is that cottage industries will eventually be established to produce the dry inoculum for sale to farmers. 

Document(s) 9 of 14