The famous olive trees of Puglia are ravaged by disease – here's how we can save them

The whole olive-growing region of Puglia has been devastated. olive grove by risteski goce/www.shutterstock.com

A common, humble field bug is spreading a disease that has already infected millions of olive trees in Italy. Olive and citrus fruit crops throughout the Mediterranean are threatened, yet there has been a collective failure to recognise the danger and take decisive action.

In Puglia in southeastern Italy, 241,000 hectares of olive groves have been restricted, with at least 10% of the 11m olive trees in the worst-affected region, Lecce, infected by the Xilella fastidiosa bacterium. The disease has almost entirely wiped out the region’s olive trees in the two years since it was first detected, and threatens the olive crop elsewhere in the country.

Olive trees often hundreds of years old are completely destroyed by the wasting disease, which leaves them looking dehydrated as if burnt. The disease has spread at epidemic levels – quickly, and with devastating effect. Besides the great economic damage, olive trees are a tremendous cultural symbol of the region, and their loss is a huge blow to the region’s identity. There’s also a convincing argument that the epidemic will spread to neighbouring regions in Italy, and on to other parts of the Mediterranean. So interested countries such as France and Greece are demanding Italy take rapid steps to control the disease, before it gets worse.

Slash and burn

Yet so far the only real action taken has been to apply the European Union protocol that requires the destruction of any olive tree and vegetation for a mile around the border of the affected zone, in this case the Salentinian Peninsula. Will this stop the diffusion of Xilella? The bacterium spreads easily as it cleverly uses a partner, the burrowing meadow spittlebug (Philaenus spumarius), one of the most abundant field insects, in order to enter the tree.

Olive trees are often hundreds of years old. fotometin

The border management strategy so far reported by the Italian and EU authorities offers only tentative steps to limit the spread of the pathogen. It’s very hard to see that this will have any significant effect: the spittlebugs are not great flyers but can be carried many kilometres in a single day by the wind or on humans or animals. Officials have also discussed an export ban on the plants, but total control is quite impossible in a region where olive trees are so important.

I was consulted immediately after the disease was discovered, but various proposals to tackle the infection were rejected in favour of a policy that only followed the EU protocol, which we know to be ineffective. Since then I and many other researchers have worked in the lab to test other solutions.

More than just pesticide

Pesticides have performed an invaluable service around the world, preventing crop losses to various insect pests, and controlling the spread of insect-borne diseases such as malaria, dengue, or yellow fever. But there are several chemicals that are no longer effective due to growing resistance – from microorganisms developing resistance to antibiotics, to insects becoming resistant to insecticides. It’s possible that in the next 20 to 30 years all the currently used pesticides will have lost their effectiveness.

It’s possible to attack the bacterium by treating the olive trees with antibiotics, but this is extremely expensive and too complicated to administer to so many trees. The spittlebugs can be controlled by insecticide — in fact the bug’s larval stage is the best route, as it’s possible to apply insecticide before they have grown wings to fly. But current chemicals are not useful, so we are working on a new line of insecticides based on natural products to tackle the Xilella problem.

Three-point plan needed

The olive tree’s disease has three main players, the bacterium, the insect, and probably a symbiotic fungus of which we understand very little, in addition to the olive plant itself. They work together, acting like a “superorganism”. It is a very complex system, but in some way also very efficient.

The only way to face the Xilella challenge is integrated pest management, tackling all elements at once. A soil treatment to sustain the plant, a larvicidal insecticide to control the spittlebug, an antifungal treatment, and a natural, low-cost and eco-friendly antibiotic to treat the plant to help prevent infection from becoming established. It’s vital that we act strongly and soon, as the disease has already spread far.

Finally, perhaps the biggest challenge will be to gain the active cooperation of the local population and farmers, who so far have only suffered damage from the loss of their trees, and for whom the idea of slashing and burning millions of century-old trees is positively sacrilegious – even if it may be the best course of action in the long term.

In flight refuelling for airliners will see non-stop services shrink the globe

Is this the future for non-stop, long-haul flights? IIAF

There’s real pressure on the aviation industry to introduce faster, cheaper and greener aircraft, while maintaining the high safety standards demanded of airlines worldwide.

Airlines carry more than three billion passengers each year, which presents an enormous challenge not only for aircraft manufacturers but for the civil aviation infrastructure that makes this extraordinary annual mass-migration possible. Many international airports are close to or already at capacity. The International Air Transport Association (IATA) has estimated that, without intervention, many global airports – including major hubs such as London Heathrow, Amsterdam Schiphol, Beijing and Dubai – will have run out of runway or terminal capacity by 2020.

The obvious approach to tackling this problem is to extend and enlarge airport runways and terminals – such as the long-proposed third runway at London Heathrow. However there may be other less conventional alternatives, such as introducing in-flight refuelling for civil aircraft on key long-haul routes. Our project, Research on a Cruiser-Enabled Air Transport Environment (Recreate), began in 2011 to evaluate whether this was something that could prove a viable, and far cheaper, solution.

Aircraft weight-watchers

The world’s first in-flight refuelling in 1923. AF.mil

If in-flight refuelling seems implausible, it’s worth remembering that it was first trialed in the 1920s, and the military has continued to develop the technology ever since. The appeal is partly to reduce the aircraft’s weight on take-off, allowing it to carry additional payload, and partly to extend its flight range. Notably, during the Falklands War in 1982 RAF Vulcan bombers used in-flight refuelling to stage what was at the time the longest bombing mission ever, flying 8,000 miles non-stop from Ascension Island in the South Atlantic to the Falklands and back.

Reducing take-off weight could offer many benefits for civilian aircraft too. Without the need to carry so much fuel the aircraft can be smaller, which means less noise on take-off and landing and shorter runways. This opens up the network of smaller regional airports as new potential sites for long-haul routes, relieving pressure on the major hubs that are straining at the seams.

There are environmental benefits too, as a smaller, lighter aircraft requires less fuel to reach its destination. Our initial estimates from air traffic simulations demonstrate that it’s possible to reduce fuel burn by up to 11% over today’s technology by simply replacing existing global long-haul flight routes with specifically designed 250-seater aircraft with a range of 6,000nm after one refuelling – roughly the distance from London to Hong Kong. This saving could potentially grow to 23% with further efficiencies, all while carrying the same number of passengers the same distance as is possible with the current aircraft fleet, and despite the additional fuel burn of the tanker aircraft.

Imagine if these Tornado fighter jets were 250-seater passenger aircraft and you’ve got the idea. Suzanne M Jenkins/USAF

However, this is not the whole picture – in-flight refuelling will require the aerial equivalent of petrol stations in order to deliver keep passenger aircraft in the sky. With so much traffic it simply wouldn’t be possible to refuel any aircraft any time, anywhere it was needed. The location of these refuelling zones, coupled with the flight distance between the origin and destination airports can greatly affect the potential benefits achievable, possibly pulling flights away from their shortest route, and even making refuelling on some routes impossible – if for example the deviation to the nearest refuelling zone meant burning as much fuel as would have been saved.

Safety and automation

As with all new concepts – particularly those that involve bringing one aircraft packed with people and another full of fuel into close proximity during flight – it’s quite right to ask whether this is safe. To try and answer this question, the Dutch National Aerospace Laboratory and German Aerospace Centre used their flight simulators to test the automated in-flight refuelling flight control system developed as part of the Recreate project.

One simulator replicated the manoeuvre from the point of view of the tanker equipped with an in-flight refuelling boom, the other simulated the aircraft being refuelled mid-flight. Critical test situations such as engine failure, high air turbulence and gusts of wind were simulated with real flight crews to assess the potential danger to the operation. The results were encouraging, demonstrating that the manoeuvre doesn’t place an excessive workload on the pilots, and that the concept is viable from a human as well as a technical perspective.

So far we’ve demonstrated the potential aerial refuelling holds for civilian aviation, but putting it into practice would still pose challenges. Refuelling hubs would need to be established worldwide, shared between airlines. There would need to be fundamental changes to airline pilot training, alongside a wider public acceptance of this departure from traditional flight operations.

However, it does demonstrate that, in addition to all the high-tech work going into designing new aircraft, new materials, new engines and new fuels, the technology we already have offers solutions to the long-term problems of ferrying billions of passengers by air around the world.

You could lose your job to a computer, so why isn't the digital economy an election issue?

All digitalled up with nowhere to plug. Crown Copyright

There seems to be a uniform impression among British politicians and legislators that the digital economy will radically transform the country for the better. A recent House of Lords select committee report on the digital economy highlighted the perils of failing to respond adequately to the opportunities it provides for future prosperity.

Why then, if the digital economy is so central to the future, is it being given so little attention during this election campaign?

The committee recommended increasing the speed and extent of broadband provision, and improving access to the internet. It’s difficult to discern the political parties’ precise approach to the digital economy until they launch their manifestos. However, looking back to the 2010 election campaign Labour, Conservatives and Liberal Democrats all agreed that developing physical broadband infrastructure was the main priority – this is not a contentious issue.

Skills, but not only skills

There are other aspects of the report that are contentious. The committee recommended extremely ambitious steps for near-universal provision of training in digital skills, despite many of the experts giving evidence to the committee arguing that basic literacy and numeracy were more important. Indeed, the speed with which computer hardware and software develops means that specific technical skills can quickly become obsolete – cognitive skills that support adapting to rapid change are arguably of more benefit in the digital economy.

There is a broader concern about the impact of automation on job security, something the committee dealt with only superficially. While acknowledging that up to 35% of jobs could disappear due to automation, it argued that these would be in low-skilled occupations.

The suggestion is that this potential loss of employment will be offset by more, higher-level jobs in the knowledge economy, no doubt filled by those workers who have honed their skills in the proposed digital skills training programmes to be offered. But, as author and Silicon Valley entrepreneur Martin Ford asserts, it is arguably knowledge workers whose jobs are as much at risk, if not primarily so, from computerisation.

Three parties, no answers

And where do the main parties stand on these issues? The Labour Party’s independent review of the impact of the digital economy on the nation’s creative industries released its report on March 27. It’s difficult to find within it any significant differences from the policies of the present government – particularly in respect of leaving unchanged UK copyright and intellectual property law.

But there is recognition of some of digital economy’s negative social effects, with recommendations to boost women’s representation in the digital creative industries, and new powers to tackle the online monopolies that are a tendency of some digital markets. While this does not represent official party policy, it’s a good indication of policy under a Labour government.

All quiet on the Westminster front, when digital economy is up for discussion. Crown Copyright/BBC

The Conservatives’ approach to the digital economy can be gleaned from the evidence provided by two ministers of state, Ed Vaizey and Nick Boles, to the Lords review. They emphasised the importance of skills-based training, much of which could be undertaken by the private sector. Also emphasised was the need to increase the number of people studying science, technology, engineering and maths at university – especially women. But the tension between the Conservatives’ promotion of free market economics and its desire for state intervention to ensure domestic security runs through the party’s approach to the digital economy. Look for example at the enormous criticism from across the tech sector of David Cameron’s wrong-headed suggestion of “banning encryption”.

The whole picture

It’s wise to highlight the great growth potential of the digital economy in the face of such political ambivalence, as per comments on the recent leaders' debate. But the other political and social implications of an increasingly digital economy need to be addressed too. For example, the mountains of e-waste from electronic devices rendered quickly obsolete, and the environmental impact of huge datacentres that power an internet economy. Yet a written submission to the committee on the digital economy’s environmental footprint was simply ignored.

The report also fails to address the sexism that runs through much of the tech industry and is evident in online communities. Dealing with the under-representation of women in these industries requires a little more sophistication than simply urging more of them to study science and engineering subjects. The tendency towards a “winner takes all” outcome in digital industries – where in an online, instantly-global market the best product wins and little is left for others (Facebook’s dominance is the classic example) – also requires some creative thinking.

As the committee’s report suggested, a much more wide-ranging and all-encompassing approach is required in order to harness the benefits of the digital economy, and to predict and prevent its potential drawbacks. This should be an approach that draws on the perspectives of the technology, arts and humanities sectors too – not just a footnote to a narrow skills-based agenda. So far, none of the parties give the slightest impression of being up to the task.

Tyrannosaurs fought and ate each other

Tyrannosaurs, shown in this artist’s illustration, both hunted for food and scavenged, which is probably how bite marks ended up on the skull of a young Daspletosaurus unearthed at Canada’s Dinosaur Provincial Park.

© Tuomas Koivurinne

The Cretaceous period was a tyrannosaur-eat-tyrannosaur world. Bite marks from before and after death scar the skull of an ancient tyrannosaur called Daspletosaurus, researchers report April 9 in PeerJ.

Paleontologists identified a fossilized skull and jaw as that of a teenage Daspletosaurus, a cousin to Tyrannosaurus rex. Some pre- and postmortem marks on the bones correspond to bite marks — big enough to come from the teeth of a Daspletosaurus or another tyrannosaur. The marks could be evidence of both combat and cannibalism, the scientists conclude.

It’s not unheard of for tyrannosaurs to fight or eat each other, but understanding the prevalence of such behavior lends insight into the extinct reptiles’ ecology.

Genome sequencing mountain gorillas reveals the genetic impact of inbreeding

Not a happy cousin. Gorilla Tracking , CC BY

Our genetic cousins, mountain gorillas, have been the subject of ongoing conservation efforts for decades. Despite this there are fewer than 900 left in the wild because of poaching and habitat destruction. Now, genetic sequencing has revealed the toll these constant threats have taken on their genome.

Our research, published in Science, reveals a striking loss of genetic diversity, but also finds more to be optimistic about than expected.

Man-made threats

Gorillas are classified into two species: one in West Africa (Gorilla gorilla) and one to the east (Gorilla beringei) in the centre of the continent. Mountain gorillas are a subspecies of the eastern gorilla species, and differ from the others in that their habitat ranges to high altitudes. This has consequences for their diet and physiology – for example, they have thicker and longer fur, which helps them survive the colder temperatures and the wetter, mistier environment.

The number of mountain gorillas living in the Virunga volcanic mountain range (on the borders of Rwanda, Uganda and the Democratic Republic of Congo) dropped to around 253 in 1981. Since then, conservation efforts have bolstered numbers there to approximately 480. There is another colony of about 400 of mountain gorillas about 30 km to the north. This adds up to only around 880 mountain gorillas surviving in the wild.

Our new research is based on blood samples collected from wild-born gorillas and is the first whole genome study; previous studies have used DNA from fecal samples or looked at much smaller sequences.

Chronic decline

Analysis of the genome data revealed that as well as suffering a dramatic collapse in numbers during the last century, mountain gorillas had already experienced a long decline going back many thousands of years. These events have resulted in a very substantial loss of genetic diversity and more inbreeding than expected: it turns out that two mountain gorillas are typically identical at more than a third of their genetic sequence – the comparable number for most humans is only a few percent.

Inbreeding increases the threat from disease and environmental change by reducing mountain gorillas' ability to adapt. It also means they carry a larger burden of harmful mutation than other gorilla species.

Silver lining

However there is a silver lining: many of the most severely harmful mutations are less common in mountain gorillas than in other gorilla subspecies, and appear to have been purged. These are mutations that disrupt the operation of a gene by prematurely terminating the protein it produces. Such mutations are expected to be more problematic than other others which may only alter the protein slightly, and some of them will be very harmful or even lethal if the protein is doing an essential job in the body.

To see why severely harmful mutations can be reduced as a result of inbreeding, consider that in a large population someone carrying such a mutation is less likely to meet and have children with another carrier. The mutation is able to persist because we have two copies of every gene, meaning it is usually only present in one copy in offspring. The lethal effect is masked by a working copy and can be passed on. However in an inbred population, carriers are more likely to meet others with the same mutation, meaning their children are more likely to have two copies, with lethal consequences for the children and preventing the mutation from being passed on.

As great apes, mountain gorillas are close evolutionary cousins of humans, so understanding their evolution also provides some insights into our own. For example, it is believed that our own ancestors also experienced severe reductions in population size at least once during human evolution, and other close relatives such as the Neanderthals went extinct in this way. Mountain gorillas thus provide an opportunity to study how humans might have adapted genetically to this condition.

Justice for poachers

It is also hoped that the detailed, whole-genome sequence data gathered through this research will aid conservation efforts in a practical way. Now that a genome-wide map of genetic differences between populations is available, it will be possible to identify the origins of gorillas that have been illegally captured or killed. This will enable more gorillas to be returned to the wild and will make it easier to bring prosecutions against those who poach gorillas for souvenirs and bush meat.

So, despite the threats they face, there are reasons to be optimistic about the future for mountain gorillas, if conservation efforts can be sustained and further encroachment on their habitat resisted. This research suggests that although low in genetic diversity, they have not yet crossed a point of no return. They can continue to survive and will return to larger numbers if we help them.

Triassic mass extinction may give clues on how oceans will be affected by climate change

Mass extinction, good news for this guy. Esparta Palma/flickr, CC BY

To hot to handle . Jessica Whiteside

Just over 200m years ago, the end-Triassic mass extinction killed off more than half of the species of organisms living on Earth’s land and in the oceans. We are only just beginning to understand how this – and the period of runaway global warming that followed – changed the chemistry of open oceans.

The end-Triassic mass extinction marked the transition between the Triassic to the Jurassic Period and the rise of the large herbivorous dinosaurs dinosaurs, such as the Diplodocus. The extinction meant that previously abundant species were cleared from ecological niches which allowed dinosaurs to move in with little competition from other animals. The Jurassic lasted another 55m years until the beginning of the Cretaceous Period.

But the extinction also had profound effects on ocean ecosystems. Previous research linked the extinction to rapid global warming and changes in ocean chemistry which were caused by massive volcanic eruptions that released large amounts of greenhouse gasses into the atmosphere. To hot to handle . jessica whiteside

One of the unanswered questions has been how global warming changed the chemistry of the oceans. Some studies provide a picture of environmental changes on land and in coastal shallow seas, but until now there has been little information on the conditions of ecosystems in open ocean areas – known as pelagic zones – where water is neither close to the seabed or the shore.

We decided to investigate this unresolved problem, as open ocean settings better reflect global conditions in comparison to shallow coastal areas, as open oceans tend not to be subject to small climatic changes experienced by other areas such as shallow coastal regions near to shore.

Toxic oceans

We extracted and analysed fossilised organic molecules – known as biomarkers – that are the remains of microscopic marine organisms from sediments deposited at the bottom of what was the north-eastern Panthalassic Ocean - the vast body of water that surround the ancient super-continent Pangaea. The sediment is now preserved as rock exposed on the coast of Haida Gwaii (also known as the Queen Charlotte Islands) off the coast of British Columbia in Canada.

Different types of biomarkers signify the presence of certain groups of organisms and allow us to track their abundance in Triassic oceans. Our results show that for a 600,000-year interval immediately after the end-Triassic mass extinction, water close to the ocean surface became devoid of oxygen and was poisoned by hydrogen sulphide, a by-product of anaerobic bacteria that is extremely toxic to most other forms of life. This oxygen depletion and hydrogen sulphide poisoning disrupted the availability of nutrients, altering the food chains and causing a major disruption of marine ecosystems.

Clues for the future

These results are similar to another major event in the geologic record that was also caused by greenhouse gas release: the end-Permian extinction, the largest-known mass extinction.

Our team’s discoveries about the end-Triassic mass extinction event have direct relevance to today’s world because we are currently experiencing a rapid rise in the atmospheric levels of the greenhouse gas, carbon dioxide (CO₂). Although the Earth was very different during the Triassic Period due to the lack of polar ice caps and higher initial CO₂ concentrations, the speed of CO₂ release from volcanic eruptions following the mass extinction is similar to those that we are experiencing today through the burning of fossil fuels.

The concern is that the consequences of rapidly rising atmospheric CO₂ levels can be expected to be similar: ocean acidification, oxygen depletion of the oceans, hydrogen sulphide poisoning and disruption of food chains through the killing off of photosynthesisers in the ocean.

Studies of ancient mass extinctions such as the one at the end-Triassic inform us of the possible consequences of our own CO₂ crisis.

System to rate the scarcity of important metals aims to keep shortage at bay

Rare earth elements, the unusual spices of the industrial world. Peggy Greb/USDA

Store cupboards usually contain the basics – canned tomatoes, soup, dry goods – but rarely the more exotic additions required in small amounts to make a dish sing. In the same way, a growing shortage of some of the rare elements needed for high-tech electronics and environmental technologies is causing manufacturers and governments to panic, with sporadic shortages leading to price spikes in some metals over the last decade.

Miners, manufacturers and governments are keen to assess the overall risk, or “criticality”, associated with different metals in order to ensure that replenishment efforts are prioritised and business can continue as usual. Of course different firms or governments will have different views, so may come up with widely varying – and hence unhelpful – estimates of criticality for the same element. But a recent study by researchers at Yale University has provided a tool based on three factors that can offer a more reliable approach to estimating metal shortfalls.

Graedel et al/PNAS

You may need only a small amount of exotic spice for your dish, but if it’s not stocked at the corner shop, it wouldn’t matter if you needed the whole jar. Similarly we can be sure that some metals – iron, aluminium – will be found in deposits suitable for mining across the world, with huge reserves that we know about – so we don’t need to worry about these dry goods equivalents. But it’s the more exotic elements such as indium and selenium, the truffle oil of our analogy, that due to geology and economics are harder to find. These are high supply risk elements, yet are essential for uses in electronics and solar cells.

Production of some metals is highly concentrated in only a few countries, leading to geopolitical risks to supply – China’s moves to restrict rare earth element exports, or strikes in South African platinum mines are recent examples.

Just like that bagged, mixed salad that’s so convenient, but wastefully irrigated and flown to Britain from Kenya at great cost, mining is a energy-hungry business. Rarer metals, such as gold and platinum, occur in concentrations as low as 1g per tonne of ore. The additional energy needed to extract and process this ore means mining these metals has a much greater environmental footprint compared to more concentrated metals, such as iron, which is the major constituent of iron ore.

The energy and environmental costs of mining rare metals are no different to the air miles for flying in out-of-season fruit from the other side of the world – and they leave these metals vulnerable to cost spikes due to rising energy costs or environmental legislation.

Vulnerability of supply

It’s possible to substitute fancier ingredients with something more common – student pasta is generally dressed with industrial cheddar rather than parmesan. Manufacturers will similarly find ways to adapt to what’s available in the face of supply restrictions, just as miners will look for fresh deposits in order to take advantage of spiking prices.

Risks to global supply and environmental consequences for 15 rare earth elements. Graedel et al/PNAS

For example the rarer metal cobalt can be substituted by the more common nickel for many uses. But other metals, such as thallium and lead, are chemically very difficult to substitute and possible substitutes are equally rare.

Another consideration is how key the ingredient is to the recipe; it might be possible to leave out a bay leaf, but there’s no coq au vin without the wine. Some metals such as gold and silver are central to world and national economies, whereas others are insignificant.

Where criticality falls down

A systematic approach such as this loses sight of details. For example, the Yale researchers' criticality system flags gold as vulnerable to supply restriction because of its wide use and lack of available substitutes. But only 10% of gold has practical uses in electronics or dentistry, so the remaining 90% largely in bank vaults or jewellery boxes could be put to use if necessary.

Also gold is the most highly recycled metal; nearly all the gold ever mined – an estimated 176,000 tonnes – remains in use. Any shortfall from restricting gold supply can easily be made up from domestic gold sales (“Your gold for cash!”).

Another issue with criticality figures is that they are a snapshot. Due to the delays in reporting figures, the study is based on 2008 statistics that are already out of date. Nor do they anticipate changes in demand – tellurium is determined to be unremarkable, yet it is essential for solar panels and demand is expected to outstrip supply by 2020, potentially bringing an abrupt halt to the roll out of sustainable solar power.

Despite these issues this study presents the most consistent picture we have of threats to metal supply, one that will be of use to industry and governments alike. More vulnerable metals can be the target of measures to reduce use, increase recycling or locate more environmentally friendly or geopolitically benign sources – such as stocking up from the local farm shop.