The fungus that caused the notorious Irish potato famine of the 1840s and 1850s is spreading among tomato and potato plants in the northeastern United States. Known as late blight, the fungus spreads easily among plants by airborne spores. This year’s epidemic has taken root at major garden retailers, eventually invading not only home gardens but also major commercial and organic farms.
The disease causes dark lesions on the plant’s leaves and stems; tomatoes then turn brown and decay, emitting a rotten odor. Although the fungus is not dangerous to people, its effects render infected plants inedible. “Late blight has never occurred this early and this widespread in the United States,” said Meg McGrath, a plant pathologist [Reuters]. Its spread has been facilitated by the cool, wet weather the Northeast has experienced this summer, along with an increased number of home gardeners looking to grow their own food as a result of the recession. This year’s blight also is particularly dangerous because of how early it appeared in the growing season; usually, the blight hits plants late, after most of the fruit has been harvested [The Baltimore Sun].
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Archaeologists have found granaries that were used to store wild cereals near the Dead Sea in Jordan more than 11,000 years ago. The structures predate agriculture in the Middle East by at least a millennium, according to a report published by the scientists in the journal Proceedings of the National Academy of Sciences.
The findings suggest that it took awhile to establish domesticated farming. In other words, the agricultural revolution likely spanned an appreciable period of time, during which our ancestors switched from hunting and gathering to growing their own food. The earliest definitive traces of domesticated grains, wheat, barley, and oats have been found in the Near East and date back about 10,500 years. Yet much recent research suggests that plant domestication was preceded by a long period–perhaps thousands of years–during which prehistoric peoples cultivated wild plants without visibly changing their appearance or altering their genetic makeup [ScienceNOW]. In archaeological digs of early villages in Israel, Jordan, Syria, and Turkey researchers have found large quantities of wild barley and wild oats, now the new findings provide evidence that the gatherers carefully stored these wild cereals.
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Leaving the rainforest of the Amazon standing has obvious benefits to the environment, as the living forests absorb and store carbon dioxide that would otherwise contribute to global warming. But cutting down the forests has been assumed to be the only route to economic development for the local people, as it provides work in the timber industry and then clears the way for farming and cattle raising. Now, a new study has found that deforestation brings only short-term and temporary economic benefits, in what researchers call a boom-and-bust cycle.
The researchers say the boom is probably due to a number of factors, including better roads and therefore better access to healthcare and schools. For a short while, the community benefits from the natural resources of the forest, and makes money off the timber and the farms that are set up in the cleared lands. But the soil is rapidly degraded making farming and cattle ranching unsustainable. “A lot of that land ends up being abandoned” [New Scientist], says study coauthor Robert Ewers.
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Pest control has never looked so sweet. Scientists have found that a simple derivative of sugar can shut down the immune defenses of ravaging termites, thus leaving the insects open to attacks from bacteria and fungus. Says lead researcher Ram Sasisekharan: “When you have an immune system that is compromised, you have a variety of opportunistic infections that take over…. You give these microbes sort of a leg up to attacking more seriously” [The Scientist].
As termites cause an estimated $30 billion in crop and building damages each year, and most current methods used to combat them rely on toxins that disrupt the termites’ nervous systems. These new findings could give rise to a whole new class of safer pest-control treatments, the authors say. “We wanted something environmentally friendly, biodegradable, and [that] does not play a toxic role” [National Geographic News], says Sasisekharan.
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The oil-rich and weedy plant jatropha has been hailed as the most promising source of biofuel on the planet, and one airline has already begun testing a jatropha-derived fuel in its jumbo jets. But a new analysis suggests that the plant may not be a miracle crop destined to solve all our energy problems: Current jatropha plantations are not realising the oil yields that drove the “Jatropha euphoria” [EcoWorldly].
It was previously thought that the hardy jatropha plant would require less water than other biofuel crops like sugarcane and corn and could grow in marginal soil, so growers wouldn’t have to take fertile land out of agricultural use. But the new study rebuts that assumption. “The claim that jatropha doesn’t compete for water and land with food crops is complete nonsense,” says study coauthor Arjen Hoekstra. The researcher says it’s true that the plant can grow with little water and can survive through periods of drought, but to flourish, it needs good growing conditions just like any other plant. “If there isn’t sufficient water, you get a low amount of oil production,” Hoekstra says [Technology Review].
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It’s not just humans who can take part in combating global warming–cows can play a role, too. Scientists say that the methane belched up by cows is a significant source of the greenhouse gas, and are searching for ways to reduce these burps. The digestive bacteria in the cows’ stomach produces the methane, which is the second-most significant gas (behind carbon dioxide) driving global warming. While methane is much less prevalent in the atmosphere than carbon dioxide, it traps heat 20 times more efficiently than carbon dioxide.
Researchers are examining a variety of tactics, including breeding or genetically engineering cows that belch less, or adjusting the bacterial mix in cows’ stomachs. But altering the cows’ feed has shown the most promise thus far. Since January, cows at 15 farms across Vermont have had their grain feed adjusted to include more plants like alfalfa and flaxseed — substances that, unlike corn or soy, mimic the spring grasses that the animals evolved long ago to eat. As of the last reading in mid-May, the methane output of [one test] herd had dropped 18 percent. Meanwhile, milk production has held its own [The New York Times].
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The concern over the declining honeybee population may be exaggerated, according to a controversial new study that shows their numbers are actually increasing globally. Alarm over a world pollination crisis is thus unfounded, say the researchers who analyzed Food and Agriculture Organization data and found that commercial domesticated bee hives have increased 45 percent in the past 50 years, to match growing demand for honey among a growing human population [AFP].
The study, published in Current Biology, says, “the declines in the U.S.A., some European countries and the former U.S.S.R. are more than offset by large increases elsewhere, including Canada, Argentina, Spain and especially China.” The study could help disprove a connection between regional declines, which have been attributed partly to parasitic mites and the general mystery known as colony collapse disorder, and a worldwide trend. But even if global bee populations continue to climb, researchers claim that there won’t be enough of them to go around. The real issue is not the honeybee numbers but the increasing work expected of them [CBC], the researchers argue.
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In another sign of Europe’s resistance to the genetically modified crops that have been widely accepted in the United States, Germany outlawed the cultivation of a genetically modified strain of corn produced by the U.S. company Monsanto. Germany joins five other countries — France, Austria, Greece, Hungary and Luxembourg — that have banned the pest-resistant maize despite its approval under a legally-binding EU directive [Nature News].
The strain of corn, known as Mon810, is the only transgenic crop approved in the European Union. Kari Matalone, a spokeswoman for Monsanto, said the corn — which is engineered to resist pests — had been approved for cultivation in Europe more than a decade ago and that no ill effects had been detected since then. “We don’t really understand where this decision is coming from,” Ms. Matalone said [The New York Times]. Monsanto also said it’s considering legal action against Germany.
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Researchers in Australia think they have found a solution to the country’s toxic cane toad problem: make Australian meat ants eat them. Cane toads—which can grow up to 8 inches (20 centimeters) in length—were imported from South America to Queensland [in northeast Australia] in 1935 in a failed attempt to control beetles on sugarcane plantations. Trouble was, the toads couldn’t jump high enough to eat the beetles, which live on top of cane stalks [AP]. Since their introduction… cane toads have spread through most of tropical Australia, eating and poisoning native animals [New Scientist]. No one has been able to get their population growth under control, and past suggestions to do so by introducing exotic diseases have only raised concerns about causing as much harm as the toads have themselves.
But a research team led by ecologist Rick Shine found that cane toads are more vulnerable to being eaten by Australia’s predatory meat ants than are native frogs, which may allow the ants to be used as a “safe” biocontrol agent that would not interfere with native frog species. Shine said the team plans to try ways of encouraging meat ants to build colonies near toad breeding ponds. One way would be to plant trees the ants favour [The Australian]. He is hopeful the strategy will work because unlike native frogs, cane toads are active during the day, when meat ants roam about scavenging for food. Toads also tend to breed in ponds that are out in the open sun, which results in their young emerging onto bare, baked mud areas, a habitat where meat ants like to forage [Sydney Morning Herald]. The toad is also more vulnerable because it lays its eggs in the dry season when water is low and there’s little protective vegetation at the pond’s edge [The Australian].
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In preparation for future oil shale mining projects near the Rocky Mountains, six oil companies have gained rights to billions of gallons of water in the American West, potentially jeopardizing water supplies throughout the region, according to a new report by Western Resource Advocates [pdf], an environmental group. It is still preliminary to speculate on the implications of the findings, but many are concerned that if the companies put their rights to use, water will be shifted away from agriculture and community use.
Using public records, the report examines more than 200 water rights held by six energy companies, including Shell and ExxonMobil, which, it is estimated, are collectively entitled to divert at least 6.5 billion gallons of water from rivers in western Colorado, as well as almost 2 million acre-feet of water from the state’s reservoirs, which is enough to supply the Denver metro area for six years. Shale oil production is a water-intensive process: up to five barrels of water are consumed for every barrel of oil produced. This means that projects producing 1.55 million barrels of oil per day would require 378,000 acre-feet of water each year, compared to the Denver metro area’s consumption, which is less than 300,000 acre feet. Should oil shale production hit full stride in the next 15 to 20 years — something the White House under President George W. Bush tried to accelerate by opening up 2 million acres controlled by the Bureau of Land Management to leasing and approving royalty rates and leasing rules — there will be a major political battle over water rights [Colorado Independent].
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In Liberia, a caterpillar infestation has turned into a national emergency. They began advancing out of the forests several weeks ago. From off in the bush, townspeople at the epicenter of the plague heard a low roar, like the sound of heavy rain cascading down through the leaves. It was caterpillar droppings. In early January, when the long, black caterpillars reached the creeks that serve as the main water sources for the town of Belefanai in north-central Liberia, the creatures’ feces instantly turned streams dark and undrinkable [National Geographic News]. Since then, things have only gotten worse. The caterpillars are eating their way through coffee and cocoa fields, and thousands of people have fled their homes.
The caterpillars are native to West Africa but have never been reported as a widespread pest in Liberia. Researchers say the cause of this population explosion is still mysterious; Liberian agriculture official Winfred Hammond says his best bet is that the boom was related to last year’s strange climate. The caterpillars live in the forest, and their population is usually kept down by wasps that lay eggs on the moth’s cocoon and eat the caterpillars, Mr. Hammond said. But the rains last year were unusual. Downpours as late as Christmas may have interrupted the reproduction cycle of the wasps that prey on the caterpillars [The New York Times].
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Locusts are prompted to band together in enormous, destructive swarms by the same brain chemical that is linked to happiness in humans. A fascinating new study has found that locusts that are about to swarm experience a sudden surge of serotonin, the same neurotransmitter that’s targeted by antidepressant drugs. “Here we have a solitary and lonely creature, the desert locust. But just give them a little serotonin, and they go and join a gang,” observed Malcolm Burrows [AP], one of the study’s authors.
Researchers say the findings may lead to methods to block the formation of locust swarms. These infestations, which can cover hundreds of square miles and involve billions of vegetation-munching insects, can devastate agriculture and cost tens of millions of dollars to control [The New York Times].
Because locusts usually avoid each other, it’s only dire circumstances that bring them together in buzzing hordes. For instance, unpredictable desert rains cause vegetation blooms, which in turn makes locust populations skyrocket. But as the rains abate and fertile land shrivels up, locusts crowd together in the remaining green patches. Eventually, the swarm trigger goes off and the locusts take to the skies—”a strategy of desperation driven by hunger,” [National Geographic News], says coauthor Stephen Rogers. When they make that behavior shift they also change appearance dramatically, going from light green to dark brown.
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Contrary to conventional wisdom, fish in the Nile delta are thriving in waters polluted with fertilizers and sewage, according to a new study. While nitrogen-rich runoff usually causes excessive growths of algae and plankton that suffocate other marine life, the Nile delta is different because it has suffered from a lack of autotrophs (that fish feed on) ever since the Aswan Dam was built in the 1960s. Researchers found that more than 60 percent of the current fishery production in the region can be attributed to human-generated runoff. “This is really a story about how people unintentionally impact ecosystems,” explained co-author Autumn Oczkowski [BBC News].
The building of the Aswan Dam on the Nile blocked off much of the fertile floodwater that drains into the Mediterranean Sea, which in turn produced a sharp fall in the number of fish being landed by Egypt’s fishermen. “But in the late 1980s, the coastal fishery began to exhibit a surprising recovery,” the researchers observed. “Today, landings are more than three times the pre-dam level” [BBC News]. The increase in fish production coincided with the rise in fertilizer use along the Mediterranean coast. To quantify the effect, researchers collected more than 600 fish from four regions contaminated by runoff and two regions that were not. In regions affected by runoff, the fish contained nitrogen isotopes that could be traced to anthropogenic sources of nitrogen, according to the study published in the Proceedings of the National Academy of Sciences.
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Domesticated pigs got their stripes and spots and other distinctive markings thanks to deliberate breeding efforts by the earliest farmers over the course of thousands of years, according to a new study of pig genetics. While there’s no clear evidence of what motivated those early farmers to change their pigs’ coats, study coauthor Greger Larson says a number of possible reasons present themselves. “One is that it facilitated animal husbandry since it is easier to keep track of livestock that are not camouflaged. Another could be that it has acted as a metaphor for the improved characteristics of the early forms of livestock compared with their wild ancestors.” But another possibility, Larson said, “is that the early farmers were as amused and as taken with biological novelty and diversity as we are today” [HealthDay News].
Novelty may have been the desired characteristic in the first agricultural settlements, but in the wild opposite forces were at work to produce pigs with a consistent brown-black color that served as camouflage. “Every time a gene mutation arose in the wild causing coat colour to change, it was eliminated immediately,” says Greger Larson…. “So if a black piglet showed up, that was the one picked off by a predator” [New Scientist].
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The ravages of global warming could be mitigated by convincing farmers around the world to plant slightly different varieties of corn, barley, and millet, according to a new study which examines the reflective properties of crop plants.Plants reflects short wave energy back out to space much like snow and other light surfaces do. This is known as the albedo effect and is a key component of calculating the effects of climate change. As Arctic ice melts and is replaced by dark water, for instance, the region’s warming is expected to accelerate. Plants have higher or lower reflectivity depending on things like the shape and size of their leaves and how waxy they are [New Scientist].
Lead researcher Andy Ridgwell and his colleagues were inspired in their work by the growing talk of geoengineering fixes for global warming, including ambitious and large-scale projects like seeding the Southern Ocean with iron to encourage algae blooms or building a huge sunshade in the Earth’s orbit. The researchers say their proposal, which they call bio-geoengineering, is more realistic because it uses existing infrastructure. “Arable agriculture is already a global-scale undertaking,” Dr. Ridgwell said. “We wondered whether you might grow slightly different crops and have some sort of climate impact.” … [I]t wouldn’t cost much, and it wouldn’t require much international cooperation. “It’s very practical, and it could just be done,” he said. “It’s not some trillion-dollar pie-in-the-sky idea” [The New York Times].
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