Anyone reading this blog will be aware of how important manioc is to the local diet. Its tuberous, starchy root is a reliable source of carbohydrates; its leaves provide some of the nutritive value that the tuber lacks. There are crops that can substitute for manioc: sweet potato and beans grow in similar conditions, though neither produces as many calories. And both of those crops must be harvested and stored, while manioc can be left in the ground until needed.
Mosaic causes the leaves of the plant to wither and lose their chlorophyll, limiting the growth of the root. I was told that the disease is worst in Mwenga, Haut Plateau, and the Ruzizi plain. Shabunda may also be affected, but no one knows: the security situation makes it too perilous to investigate. The Gates Foundation funds something called the Great Lakes Cassava Initiative (cassava being another word for manioc). Here's a video about their work. Their main goal is to distribute a mosaic-resistant variety of manioc with better yields. The problem is that manioc is propagated by cuttings, not by seeds. That means it takes time to develop enough stock of the new variety. Bernard Assuman, the provincial inspector for agriculture, told me that progress is being made, but that it will take about five years before the improved manioc is disseminated province-wide.
It was hard for me to gauge just how severe and widespread the problem is. All I can report is that several villagers in separate villages in South Kivu independently approached me to complain about it. The market ladies in Bukavu told me that price of manioc flour went up by about 50 percent two to three years ago, but hasn't budged lately. If mosaic is spreading in a patch-work pattern throughout the countryside, it could be devastating individual farmers or villages while leaving others untouched. A quick internet search yielded nothing relevant on the extent to which mosaic is causing hunger in rural Congo. That in itself is troubling. More research is clearly needed.