Scientists Have No Idea How to Fight Citrus Greening
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.
A "trash tsunami" has washed ashore on the beaches of Honduras, endangering both wildlife and the local economy.
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More long-finned pilot whales were found stranded today on beaches in Tasmania, Australia. About 500 whales have become stranded, including at least 380 that have died, the AP reported. It is the largest mass stranding in Australia's recorded history.
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By Harry Kretchmer
By 2030, almost a third of all the energy consumed in the European Union must come from renewable sources, according to binding targets agreed in 2018. Sweden is helping lead the way.
Sweden is a world leader in renewable energy consumption. Swedish Institute/World Bank
Naturally Warm<p>54% of Sweden's power comes from renewables, and is helped by its geography. With plenty of moving water and 63% forest cover, it's no surprise the <a href="https://sweden.se/nature/energy-use-in-sweden/#" target="_blank">two largest renewable power sources</a> are hydropower and biomass. And that biomass is helping support a local energy boom.</p><p>Heating is a key use of energy in a cold country like Sweden. In recent decades, as fuel oil taxes have increased, the country's power companies have turned to renewables, like biomass, to fuel local 'district heating' plants.</p><p>In Sweden these trace their <a href="https://www.sciencedirect.com/science/article/pii/S0360544217304140#fig3" target="_blank">origins back to 1948</a>, when a power station's excess heat was first used to heat nearby buildings: steam is <a href="https://www.sciencedirect.com/topics/engineering/district-heating-system" target="_blank">forced along a network of pipes</a> to wherever it's needed. Today, there are around 500 district heating systems across the country, from major cities to small villages, providing heat to homes and businesses.</p><p>District heating used to be fueled mainly from the <a href="https://www.sciencedirect.com/science/article/pii/S0360544217304140" target="_blank">by-products of power plants</a>, waste-to-energy plants and industrial processes. These days, however, Sweden is bringing more renewable sources into the mix. And as a result of competition, this localized form of power is now the country's<a href="https://www.sciencedirect.com/science/article/pii/S0360544217304140#fig3" target="_blank" rel="noopener noreferrer"> home-heating market leader.</a></p>
Sweden is using smart grids to turn buildings into energy producers. Huang et al/Elsevier
Energy ‘Prosumers’<p>But Sweden doesn't stop at village-level heating solutions. Its new breed of energy-generation takes hyper-local to the next level.</p><p>One example is in the city of Ludivika where 1970s flats <a href="https://www.buildup.eu/sites/default/files/content/transforming-a-residential-building-cluster-into-electricity-prosumers-in-sweden.pdf" target="_blank">have recently been retrofitted with the latest smart energy technology</a>.</p><p>48 family apartments spread across 3 buildings have been given photovoltaic solar panels, thermal energy storage and heat pump systems. A micro energy grid connects it all, and helps charge electric cars overnight.</p><p>The result is a cluster of 'prosumer' buildings, producing rather than consuming enough power for 77% of residents' needs. With <a href="http://www.diva-portal.org/smash/get/diva2:1232060/FULLTEXT01.pdf" target="_blank" rel="noopener noreferrer">high levels of smart meter usage</a>, it's a model that looks set to spread across Sweden.</p>
<div id="d7bf9" class="rm-shortcode" data-rm-shortcode-id="8757b138d5570bec9d6aad18074a429a"><blockquote class="twitter-tweet twitter-custom-tweet" data-twitter-tweet-id="1273556364263071744" data-partner="rebelmouse"><div style="margin:1em 0">Read more about Western Harbour and book a visit: https://t.co/ujSmVs9rNK 🏡🌳🌊 https://t.co/C5PuPziqIM</div> — Smart City Sweden (@Smart City Sweden)<a href="https://twitter.com/SmartCitySweden/statuses/1273556364263071744">1592474473.0</a></blockquote></div>
Scaling Up<p>A recent development by E.ON in Hyllie, a district on the outskirts of Malmö, southern Sweden, <a href="https://www.eonenergy.com/blog/2019/February/sweden-smart-city" target="_blank">has scaled up the smart grid principle</a>. Energy generation comes from local wind, solar, biomass and waste sources.</p><p>Smart grids then balance the power, react to the weather, deploying extra power when it's colder or putting excess into battery storage when it's warm. The system is not only more efficient, but bills have fallen.</p><p>Smart energy developments like those in Hyllie, Ludivika, and renewable-driven district heating, offer a radical alternative to the centralized energy systems many countries rely on today.</p><p>The EU's leaders have a challenge: how to generate 32% of energy from renewables by 2030. Sweden offers a vision of how technology and local solutions can turn a goal into a reality.</p>
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By Jessica Corbett
In another win for climate campaigners, leaders of 12 major cities around the world — collectively home to about 36 million people — committed Tuesday to divesting from fossil fuel companies and investing in a green, just recovery from the ongoing coronavirus pandemic.
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