Bringing science and development together through news and analysis

  • Coloured pesticides protect African farmers

Researchers in Nigeria have come up with a novel way of helping farmers to use pesticides safely — by adding coloured dye to the chemicals to show just how far pesticides spread during spraying.

Many farmers in Africa rely on leaky knapsack sprayers and bottles to apply pesticides to crops. They often fail to notice when chemicals splash onto their skin, which can cause a variety of side effects ranging from itchy skin and eyes to headaches and vomiting.

Scientists from the International Institute of Tropical Agriculture (IITA) in Ibadan, Nigeria, added blue dye to pesticides and asked volunteer farmers to test the spraying equipment when dressed in white overalls. The blue liquid leaked from old nozzles and breaks in the equipment, and also sprayed back from plants onto their white clothing.

"Farmers are smart. They know they should be careful when applying agrochemicals," says IITA agronomist Ole Nielson. "If these contained dye, they could see directly where the chemical ended up and they would be even more careful." As a result they would be less likely to eat with contaminated hands or forget to wash carefully after spraying.

Barbara Dinham, director of Pesticide Action Network UK, which aims to reduce pesticide-related hazards, says that to her knowledge this is the first time that dyes have been used to alert farmers to the dangers of pesticides in this way.

"It is certainly a visual reminder," she says. "But it is of limited value if farmers don't have any choice of whether or not to use pesticides. Farmers need to have other alternatives."

The IITA tests were conducted at workshops held earlier this year as part of a weed control project funded by the UK's Department for International Development. Scientists there will now be recommending chemical companies to colour their products so that farmers can see whether they have been contaminated. They have also started distributing safety pamphlets to promote sprayer safety.

© SciDev.Net 2003

Photo credit: © IITA