Cassava crop disease spreads uncontrollably across Africa
JOHANNESBURG — Scientists say a disease destroying entire crops of cassava has spread out of East Africa into the heart of the continent, is attacking plants as far south as Angola and threatens to move west into Nigeria, the world's biggest producer of the potato-like root that helps feed 500 million Africans.
“The extremely devastating results are already dramatic today but could be catastrophic tomorrow” if nothing is done to halt the Cassava Brown Streak Disease, said scientist Claude Fauquet, co-founder of the Global Cassava Partnership for the 21st Century.
Africa, with a burgeoning population and debilitating food shortages, is losing 50 million tons of cassava to the disease a year, he said.
In Uganda, a strain of the virus identified five years ago is destroying 45 percent of the national crop and as much as 80 percent of harvests in some areas, according to a new survey, said Chris Omongo, an entomologist and cassava expert at Uganda's National Crops Resources Research Institute.
“The new strain looks to us to be much more aggressive,” Omongo said.
Fauquet said one problem is that the virus attacks the tubers underground, so a farmer can husband his crop for as long as 18 months and only realize when he goes to dig up the cassava that all his fields are infected.
Omongo has participated in a training video — funded by U.S. aid to the Association for Strengthening Agricultural Research in Eastern and Central Africa — where farmers in north Tanzania are shown digging up cassava and cutting into roots turned black and brown with rot. The farmers say the rotten bits taste bitter and are inedible. They say they spend hours trying to chop away blighted parts.
The disease is spreading too fast to measure its impact, scientists say.
A moderate infection with up to 30 percent root damage decreases the market value of cassava tubers drastically, to less than $5 a ton instead of $55, according to a study published last year in the journal Advances in Virology.
“Recent estimates indicate that CBSD causes economic losses of up to $100 million annually to the African farmer, and these are probably an underestimate, as the disease has since spread into new areas,” the article said.
Africa produced 150 million tons of the global harvest of 250 million tons last year, with Nigeria alone producing 50 million tons, according to Fauquet.
The cassava disease is endemic along the Indian Ocean coast of East Africa, affecting Kenya, Tanzania and Mozambique. In the past, it had not struck at high altitudes. But recently, the disease has been found at up to nearly 5,000 feet above sea level in Uganda, Congo and Tanzania's lake zones, the article in Advances in Virology reported. The disease also is found in Burundi and Rwanda.
In the past year, Fauquet said, symptoms of the virus have been found as far south as Angola and moving into West Africa. The white fly that acts as a vector for the disease has been spotted in Cameroon, in central Africa, and in Zambia to the south.
“If the disease makes it to the Congo Basin, which is a big cassava producer, and — really frightening — reaches West Africa and Nigeria, the biggest producer, you can just imagine the impact, the magnitude,” Fauquet said.
This week, scientists are meeting in Bellagio, Rome, to discuss what can be done.
Fauquet said what is needed is the kind of international effort that the West put into developing a virus-free potato post World War II, ending the chance of a disaster such as the Irish potato famine. Similar work has been done on other crops in the past 50 years, including sugar cane and sweet potatoes, he said.
Show commenting policy
TribLive commenting policy
You are solely responsible for your comments and by using TribLive.com you agree to our Terms of Service.
We moderate comments. Our goal is to provide substantive commentary for a general readership. By screening submissions, we provide a space where readers can share intelligent and informed commentary that enhances the quality of our news and information.
While most comments will be posted if they are on-topic and not abusive, moderating decisions are subjective. We will make them as carefully and consistently as we can. Because of the volume of reader comments, we cannot review individual moderation decisions with readers.
We value thoughtful comments representing a range of views that make their point quickly and politely. We make an effort to protect discussions from repeated comments either by the same reader or different readers.
We follow the same standards for taste as the daily newspaper. A few things we won't tolerate: personal attacks, obscenity, vulgarity, profanity (including expletives and letters followed by dashes), commercial promotion, impersonations, incoherence, proselytizing and SHOUTING. Don't include URLs to Web sites.
We do not edit comments. They are either approved or deleted. We reserve the right to edit a comment that is quoted or excerpted in an article. In this case, we may fix spelling and punctuation.
We welcome strong opinions and criticism of our work, but we don't want comments to become bogged down with discussions of our policies and we will moderate accordingly.
We appreciate it when readers and people quoted in articles or blog posts point out errors of fact or emphasis and will investigate all assertions. But these suggestions should be sent via e-mail. To avoid distracting other readers, we won't publish comments that suggest a correction. Instead, corrections will be made in a blog post or in an article.
- France honors attack victims in city subdued by mourning
- France hails 130 victims of Paris terrorist attacks
- Russia’s war room in multibillion-dollar Moscow control center grand, modernized
- Suicide bomber targets crowd of Shiites in Nigeria
- Russia scoffs at alliance with West on Syria
- Turkey releases recording of warnings to Russian plane
- Pope Francis plugs global climate talks in Kenya visit
- Slaying in Venezuela spurs fears of political violence
- South African judge OKs local trade in rhino horns
- Mexico seizes El Chapo’s planes, cars, houses
- In Uganda, Pope Francis pays tribute to nation’s martyrs