UN warns of staple crop virus 'epidemic'
Cassava is one of the world's most important crops providing up to a third of the calorie intake for many people.
The food and agriculture organisation of the UN says the situation is urgent and are calling for an increase in funding for surveillance.
None of the varieties of cassava being distributed to farmers in Africa appears to be resistant to the virus.
Cassava is a global food source of particular importance in Africa as it does well on poor soils with low rainfall.
But like many crops it is threatened by a number of pests and diseases that hinder its production. Viral infections have periodically wiped out the crop in some regions leading to famine.
Now the UN's Food and Agriculture Organization (FAO) says that another virus is threatening the crop in large parts of East Africa.
The scientists say the Cassava Brown Streak Disease (CBSD) is on the verge of becoming an epidemic. It first appeared in Uganda in 2006 but in the past few months has been found in Burundi and the Democratic Republic of Congo for the first time. more