8 June 2001

Eco-friendly fossils

GROUND fossils could prove an eco-friendly alternative to chemical pesticides on stored grain, according to work at the University of Greenwich.

Diatomaceous earth (DE), a substance derived from phytoplankton fossils found in chalk deposits, is readily processed into a dust, and researchers from the Natural Resources Institute have been examining its potential.

Mixed with grain the dust absorbs the waxy outer layers of insects, dehydrates and kills them, they have discovered.

Trials in Zimbabwe are said to have found DE as effective as organophosphate pesticides and far safer, the dust being almost harmless to humans and other mammals. Insect control for up to eight months has been achieved.

African farmers are concerned about the health implications of mixing costly and hard to get conventional pesticides with grain, says the NRIs Tanya Stathers. &#42