Nonchemical weedkiller has huge potential; hungriest nations may benefit thanks to McGill plant ...( McGill University plant scienti...)

McGill University plant scientist Dr. Alan Watson and research associate Marie Ciotola in the Faculty of Agricultural and Environmental Sciences believe they can help farmers in Africa recover desperately needed agricultural land invaded by a noxious weed known as Striga, or witchweed. Field trials in Mali led by the Biopesticide Research Laboratory have produced spectacular results using a naturally occurring pathogen, Fusarium. "Most of the Striga was wiped out and crop yields doubled," says Dr. Watson. Not only that, the researchers figured out a way to manufacture the Fusarium locally, which provides farmers and women in the community with more economic and social power.

Currently one of the greatest obstacles to food production in Africa, the parasitic Striga, described as "a pretty flower but a deadly weed," thrives in areas of poor soil and infests two thirds of land devoted to cereal crops. "The losses can be as high as 70% among subsistence farmers," says Dr. Watson. The weed compensates for its own lack of root system by penetrating the roots of other plants and stunting their growth.

Dr. Watson and his colleagues evaluated 250 organisms and were gratified to find that the Fusarium pathogen attacked the seeds as well as the plant. The next challenge was to find a way to make the fungus available to farmers. Researchers came up with a starter culture in a capsule, which could be fermented and dried locally. The farmers have their seed coated first with wet arabic gum, which acts as an adhesive, and then with the Fusarium inoculant. Once the seeds are planted, the rain activates the Fusarium inoculant and makes it available exactly where it is needed: at the roots of the cereal plant.

Using inexpensive, locally available ingredients like sorghum straw and arabic gum, the process of preparing the dried fungus involves cooking pots and boiling water, women1s traditional sphere of
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Contact: Andrea De Rome
derome@macdonald.mcgill.ca
514-398-7666
McGill University
20-Dec-1999