Quantcast

Scientists Have No Idea How to Fight Citrus Greening

Food
Alf Ribeiro / Shutterstock

By Dan Nosowitz

Since 2012, when it was first found in California and Texas, scientists have been searching for a solution to a "citrus greening," a devastating disease affecting citrus trees.


Citrus greening, known as huánglóngbìng in China (shortened to HLB in America), where it's been present for decades, is an intensely destructive disease, sneakily killing branches, causing bitter, unsellable fruit and stunting growth. Unfortunately, a new report from the National Academies of Sciences, Engineering and Medicine says that a solution is not coming anytime soon.

Florida, which is responsible for most of the juice oranges produced in the U.S., is being wrecked by citrus greening. It's estimated that the disease has caused $2.9 billion in damages between 2007 and 2014 (it was first discovered in Florida in 2005), and it's thought to be a key contributor to the decline of citrus acres in the state.

As a result, the Citrus Research and Development Foundation (CRDF), an industry group, has poured about $100 million into attempting to solve this problem. Citrus greening is caused by a bacteria that's spread by the Asian citrus psyllid, a tiny, brown, moth-like insect that's actually a pretty annoying pest in its own right. But it's most destructive as a vector for the bacteria that causes citrus greening.

The CRDF asked the Academies to take a look at their research and attempt to figure out any possible solution. In response, this week, the Academies released a study calling a silver bullet "unlikely." From the study's release: "Significant barriers to progress toward an HLB solution still exist, among them the inability to culture the bacteria in the laboratory, the lack of advanced diagnostics for early disease detection, and the absence of standardized research methodology that would improve the comparability of results across studies."

The report doesn't rule out the possibility of long-term solutions, including some involving genes taken from spinach, but notes that short-term solutions, especially preventative measures, might be the most effective for now.

On that note, short-term solutions for citrus greening have actually been known for awhile. The Florida Department of Citrus recommends better nutrition for the trees themselves; apparently well-fed citrus trees are more able to produce good fruit when hit by citrus greening. The University of Florida suggests more careful sourcing of trees in the first place, and the outright removal of any infected trees. There's also this guide to antibacterial product use; possible products include streptomycin (well-understood, though highly toxic to algae) and oxytetracycline (which the EPA says is basically fine). But none of these are great solutions; they're kind of all just best practices for growing citrus, and the decline in productivity and the spread of citrus greening suggests that these preventative practices are not especially effective solutions.

Reposted with permission from our media associate Modern Farmer.

EcoWatch Daily Newsletter

Matt Cardy / Stringer / Getty Images

The Guardian is changing the way it writes about environmental issues.

Read More Show Less
Blueberry yogurt bark. SEE D JAN / iStock / Getty Images Plus

By Lizzie Streit, MS, RDN, LD

Having nutritious snacks to eat during the workday can help you stay energized and productive.

Read More Show Less
Sponsored
A 2017 flood in Elk Grove, California. Florence Low / California Department of Water Resources

By Tara Lohan

It's been the wettest 12 months on record in the continental United States. Parts of the High Plains and Midwest are still reeling from deadly, destructive and expensive spring floods — some of which have lasted for three months.

Mounting bills from natural disasters like these have prompted renewed calls to reform the National Flood Insurance Program, which is managed by Federal Emergency Management Agency and is now $20 billion in debt.

Read More Show Less
Jennifer A. Smith / Moment / Getty Images

By Brenda Ekwurzel

When temperatures hit the 80s Fahrenheit in May above latitude 40, sun-seekers hit the parks, lakes, and beaches, and thoughts turn to summer. By contrast, when temperatures lurk in the drizzly 40s and 50s well into flower season, northerners get impatient for summer. But when those 80-degree temperatures visit latitude 64 in Russia, as they just did, and when sleet disrupts Mother's Day weekend in May in Massachusetts, as it just did, thoughts turn to: what is going on here?

Read More Show Less
Shrimp fishing along the coast of Nayarit, Mexico. Tomas Castelazo / Wikimedia, CC BY-SA

By Paula Ezcurra and Octavio Aburto

Thousands of hydroelectric dams are under construction around the world, mainly in developing countries. These enormous structures are one of the world's largest sources of renewable energy, but they also cause environmental problems.

Read More Show Less
Sponsored
Activists in North Dakota confront pipeline construction activities. A Texas bill would impose steep penalties for such protests. Speak Freely / ACLU

By Eoin Higgins

A bill making its way through the Texas legislature would make protesting pipelines a third-degree felony, the same as attempted murder.

Read More Show Less
An Australian flag flutters in the wind in a dry drought-ridden landscape. Virginia Star / Moment / Getty Images

Australia re-elected its conservative governing Liberal-National coalition Saturday, despite the fact that it has refused to cut down significantly on greenhouse gas emissions or coal during its time in power, The New York Times reported.

Read More Show Less
Tree lined street, UK. Richard Newstead / Moment / Getty Images

The UK government will fund the planting of more than 130,000 trees in English towns and cities in the next two years as part of its efforts to fight climate change, The Guardian reported Sunday.

Read More Show Less