CORVALLIS, Ore. – The widespread use of pesticides in West Africa poses a significant risk to the environment and human and animal health, according to a new study by Oregon State University. 

OSU trained village leaders in five African countries—Guinea, Mali, Mauritania, Niger and Senegal—to record details of crop production and pesticide use by farmers. This information was then used to calculate the risks that these agricultural chemicals pose.

team of researchers
A team of Oregon State University researchers
has surveyed pesticide use in West Africa,
documenting extreme risks to the environment
and human and animal health.
(Photo by Paul Jepson.)

"The knowledge of locals is crucial to collecting data and calculating risks," said Paul Jepson, director of OSU's Integrated Plant Protection Center. "Pesticides are treated like medicine in a way in West Africa, based on their potential to help protect crops from pests." 

OSU researchers found that pesticide use West Africa is highly inefficient and often transported through air, soil and ground and surface water. Beneficial bugs—those that hunt pests—often too killed by toxic exposure. 

Pesticides are applied heavily to West African crops to combat pests, such as grasshoppers, locusts, quelea bird, butterfly larvae and aphids. 

Jepson has just returned from West Africa where OSU is now explaining the results of their work to farmers. 

"Helping growers understand risks through education is the first step to improving health, the environment and agricultural yield," he said. 

Among the findings:

  • Protective clothing that reduces exposure to chemicals is largely unknown and unavailable in West Africa.
  • It could take up to three weeks following a pesticide spray in West Africa for risks to fall to low-enough levels to reenter a field, OSU researchers calculated.
  • Pesticide imports outpace the growth of agricultural production and are subject to low duty rates in Africa, reducing the incentive for alternatives. 
  • Low literacy levels limit the potential for written information to be used to reduce chemical risks.
  • Wildlife populations, particularly birds, and fish populations are also threatened throughout the region by pesticides. OSU identified the locations and areas over which different pesticides are having a significant negative impact.
  • Graduates of farmer field schools—which teach growers how to manage threats to crops—use 80 percent fewer pesticides.

By 2050, the world will be unable to meet its needs for food through current cultivation practices, according to the Kavli Declaration, which was signed by top agricultural researchers throughout the world, including Jepson and OSU professors Kim Anderson and John Antle.

To meet increasing demand, food production in West Africa needs to increase to help feed a growing world population, according to researchers.

"We must radically change the way we grow food and protect against pests to feed 9 billion people by mid century. Pest management in Africa can help us move closer to that goal," said Jepson a professor in OSU's College of Agricultural Sciences.

The journal Philosophical Transactions of the Royal Society published three studies by OSU and their collaborators about extension education, pesticide monitoring and pesticide risks in West Africa on February 17th.

OSU developed the surveys working in cooperation with the United Nations Food and Agriculture Organization and West African non-governmental organizations.

By Daniel Robison, 541-737-1386,
Source: Paul Jepson, 541-737-9082,

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