Cassava brown streak disease: historical timeline, current knowledge and future prospects

Katie R Tomlinson,Sue Seal,Titus Alicai,Andy M Bailey,Gary D Foster

doi:10.1111/mpp.12613

Abstract

SummaryCassava is the second most important staple food crop in terms of per capita calories consumed in Africa and holds potential for climate change adaptation. Unfortunately, productivity in East and Central Africa is severely constrained by two viral diseases: cassava mosaic disease (CMD) and cassava brown streak disease (CBSD). CBSD was first reported in 1936 from northeast Tanzania. For approximately 70 years, CBSD was restricted to coastal East Africa and so had a relatively low impact on food security compared with CMD. However, at the turn of the 21st century, CBSD re‐emerged further inland, in areas around Lake Victoria, and it has since spread through many East and Central African countries, causing high yield losses and jeopardizing the food security of subsistence farmers. This recent re‐emergence has attracted intense scientific interest, with studies shedding light on CBSD viral epidemiology, sequence diversity, host interactions and potential sources of resistance within the cassava genome. This review reflects on 80 years of CBSD research history (1936–2016) with a timeline of key events. We provide insights into current CBSD knowledge, management efforts and future prospects for improved understanding needed to underpin effective control and mitigation of impacts on food security.

Highlights

Cassava (Manihot esculenta Crantz, family Euphorbiaceae) produces carbohydrate-rich storage roots, which are a staple food crop for approximately 800 million people worldwide [Food and Agriculture Organization (FAO), 2013]
Productivity in East and Central Africa is significantly constrained by two viral diseases, cassava mosaic disease (CMD) and cassava brown streak disease (CBSD), which together are estimated to cause annual losses worth US$1 billion [International Institute of Tropical Agriculture (IITA), 2014a] and adversely affect food security in the entire region (Patil et al, 2015)
It is not known whether CBSD had been re-introduced to Uganda through infected cuttings or whether the disease had existed at a low level since it was first introduced in the 1940s (Alicai et al, 2007)

Summary

SUMMARY

Cassava is the second most important staple food crop in terms of per capita calories consumed in Africa and holds potential for climate change adaptation. For approximately 70 years, CBSD was restricted to coastal East Africa and so had a relatively low impact on food security compared with CMD. At the turn of the 21st century, CBSD re-emerged further inland, in areas around Lake Victoria, and it has since spread through many East and Central African countries, causing high yield losses and jeopardizing the food security of subsistence farmers. This recent re-emergence has attracted intense scientific interest, with studies shedding light on CBSD viral epidemiology, sequence diversity, host interactions and potential sources of resistance within the cassava genome.

INTRODUCTION

Findings

CONCLUSIONS