Insects damage huge amounts of harvested grain in sub-Saharan Africa, causing serious losses for smallholder farmers and traders. This threatens people’s food security and their self-sufficiency when their seed corn is lost. It also often means that they have to cut their losses and sell their grain early—rather than waiting until the best prices are available. Use of imported synthetic chemical pesticides can limit insect damage. But, many farmers fear that treating stored grain with pesticides will contaminate their food and damage their health. Those who try to avoid this by using traditional grain treatments such as ash and sand often don’t get the results they need. Diatomaceous earths offer a safer alternative to chemical pesticides that small-scale farmers can use to reduce the damage that insects do to their stored grain. This booklet gives the background to the problem in stored grain in Africa, and details of how to use diatomaceous earths to protect against storage pests.