Without any effort at all, Hawa Saidi Ibura crushes dried beans, one at a time, between her fingers outside her home in Endagaw, a village in northern Tanzania.

She’s holding a basket of a type of red bean eaten all over East Africa, but these beans are skeletons of what they once were. She harvested them from her farm less than a year ago, but insects have since ravaged her storage room—eating the nutrition out of the beans and out of her corn, too. Although the insects likely don’t contaminate the beans, meaning there’s no health hazard in eating them, the remains are not the most desirable or nutritious food, and farmers like Ibura would much prefer to buy new beans—an option many can’t afford. So this is the crop she’s left with until the next harvest, months away.

Ibura is far from alone. Small-scale farmers all over Africa and in other developing regions around the world struggle with a surprisingly basic problem: They grow crops like corn and beans for subsistence and to sell as their main source of income, but they lack a storage system to keep those crops safe from insects and rodents. So even if they have a bumper crop, farmers can run out of food a few months after harvest because it’s been eaten in their storage rooms.

Beans and sorghum are particularly vulnerable. So is corn, one of the most important staple crops in many African countries and a crop that has among the most available statistics for quantities lost after harvest. Farmers and traders lose between about 15 and 25 percent of the corn crop once it’s been harvested, according to the African Postharvest Losses Information System, a European Commission–financed database and network of cereal experts in East and southern Africa. Precise estimates, however, vary from region to region, year to year and crop to crop.

Pesticides are available, and farmers do apply them to stored crops, but many can’t afford a full dose. Possibly more problematic, the pesticides are often expired or adulterated, and many farmers don’t know the proper application rates. Overapplying pesticides can be toxic, while underapplying can help insects develop resistance to their effects.

That’s why some farmers near Arusha, a city in northern Tanzania, are looking with optimism to research underway at the nearby Nelson Mandela African Institution of Science and Technology. For her thesis project, graduate student Angela Mkindi is testing a pesticide powder she’s made from extracts of four local plants. She’ll apply the powder to cowpeas, a popular legume in East Africa that is vulnerable to insect infestation. Research last year by another student showed promising results for the same mixture in a laboratory experiment, so Mkindi is taking that research to the farm level, trying to replicate the way local farmers grow and store beans as closely as she can.