Funded by the Bill & Melinda Gates Foundation and the UK Department for International Development, the Cassava Diagnostics Project (CDP) has been working with institutes across East Africa since 2009 to diagnose, track and sustainably manage cassava viruses. Cassava is a staple crop for 500 million people in Africa and is currently threatened by two devastating viral diseases: cassava mosaic disease (CMD) and cassava brown streak disease (CBSD). CDP has therefore been working to combat these diseases and so prevent widespread famine – by ensuring that cassava remains a reliable food source across Africa. As CDP closes, Dr Fred Tairo (Principal Agricultural Research Officer) reflects on how CDP has combated the spread of cassava viruses in Tanzania.