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Quicksilver Ants Break Sprint Records

Saharan insects use breakneck speeds to beat the desert heat while finding food.

ant_cropped.jpg

Saharan silver ants on sand.

Image credits: Pavel Krasensky/Shutterstock

Wednesday, October 16, 2019 – 18:00

Joshua Learn, Contributor

(Inside Science) — The world’s fastest known ant can reach speeds that would make even Usain Bolt appear sluggish, and they can do this in desert temperatures that sometimes reach 140 degrees Fahrenheit.

The Saharan silver ant can reach speeds of nearly a meter per second, or 108 body lengths per second. In human terms, this body-lengths-per-second speed would be the equivalent to about 430 miles per hour if you were around 5 feet, 10 inches tall.

“They go out in midday hours, which sounds more or less crazy or absurd,” said Sarah Pfeffer, a post-doctoral researcher at the University of Ulm in Germany and the lead author of a study published today in the Journal of Experimental Biology.

While many desert creatures keep underground during the day to avoid the worst of the heat, the Saharan silver ant takes advantage of the high temperatures to avoid predators and scavenge for scarce resources. The ants mostly eat dead insects like fruit flies or locusts that may not have made it to shelter before the heat did them in.

“They need to be very fast because the Sahara is very hot and they have found a special ecological niche,” Pfeffer said, adding that not many other scavengers are out at this time. One single ant track measured 5,000 feet. In human terms that would be like someone walking more than 30 miles in the hot desert sun in search of a meal.

The researchers tracked the ants using high-speed cameras, and found that they accomplish their athletic feats by bouncing off three legs at once in tripod-like formations, resulting in a type of gallop that had their entire body off the ground between each stride. The insects can take 47 of these strides per second.

The ants still have their limits, Pfeffer said. They would succumb to the heat if their body temperatures reached about 128 degrees Fahrenheit, meaning a need for speed in finding food and hauling it back to the cool of their nest is essential.

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Author Bio & Story Archive

portrait of writer Joshua Learn, posed with a brick wall behind him. Learn has dark hair and is wearing a blue shirt.

Joshua Rapp Learn (@JoshuaLearn1) is an expat Albertan based in Washington, D.C. He reports on science for publications like National Geographic, New Scientist, Smithsonian, Scientific American, Washington Post, The Atlantic, Science and Hakai.

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Scientists Can Now Predict Which Invasive Insects Will Wipe Out Forests

Surprisingly, it’s the trees, not the bugs, that matter.

Monday, November 4, 2019 – 10:00

Gabriel Popkin, Contributor

(Inside Science) — Plagues of forest-destroying insects seem to arrive on our shores almost as regularly as ocean waves. Their names — hemlock woolly adelgid, emerald ash borer, Asian longhorned beetle, spotted lanternfly — only hint at the damage they trigger. The dead trees they leave behind cost billions to remove and add more than 5 million metric tons of carbon annually to the atmosphere, an amount roughly equal to the annual output of 4.4 million cars.

Yet for each major tree killer, around half a dozen foreign insects live quietly in our forests, causing few noticeable problems. A new study may help scientists pick out the future tree killers from the crowd, and it has a surprising conclusion: It’s the characteristics of the trees that insects feed on, not the insects themselves, that matter.

“It’s just the kind of research that we need,” said Gary Lovett, an ecologist at the Cary Institute of Ecosystems Studies in Millbrook, New York, who was not involved in the research.

Efforts to predict invasive tree killers go back decades. But many have simply tried to determine which insects could get established in a new environment, said Nathan Havill, an entomologist with the U.S. Forest Service in Hamden, Connecticut.

Predicting which invasions will have major impacts “has been referred to as the holy grail of invasion biology,” said Angela Mech, an entomologist at Western Carolina University in Cullowhee, North Carolina.

To tackle the problem, Mech, then at the University of Washington in Seattle, Havill and other researchers constructed a database of the 58 known nonnative insects that feed on American conifers, including pines, hemlocks, spruces, and firs.

In their database, the scientists included insect traits such as how many times the species reproduces each year and whether it feeds on sap, leaves or bark. They also included the characteristics of trees, such as growth rate, habitat and how long ago they emerged as distinct species. And the researchers developed a metric to separate “high-impact” insects such as hemlock woolly adelgid from more benign ones.

The analysis revealed that the best predictor of a foreign insect’s tree-killing potential is the amount of time since the tree the insect lives on diverged from its closest ancestor in its native country. But the relationship isn’t simple: Insects living on trees that diverged long ago or very recently were much less destructive than ones that were in what Mech called a “Goldilocks time frame” of 12 million to 17 million years ago for sap feeders and 1.5 million to 5 million years ago for leaf eaters.

The existence of these time windows “was a very unique and exciting result of this that we weren’t necessarily predicting,” Havill said.

The authors believe that insects whose native and potential new host trees diverged long ago are less able to use trees encountered in their new homes as a major food source. Meanwhile, recently diverged trees are more likely to still produce defensive chemicals to fend off nonnative insects.

Two other factors also stood out. Conifers that can grow in shade but can’t handle drought are more likely to get hit with insect plagues. And trees that are already fed on by a native insect in the same genus as a foreign insect are less vulnerable to the nonnative interloper.

Using these three factors, the authors wrote that they can assign the most dangerous insects a 1-in-6.5 chance of becoming a major tree killer; the least dangerous have a less than 1-in-2,800 chance. Though the scientists haven’t yet attempted to pinpoint the most dangerous foreign insects still waiting to be introduced, some patterns are emerging. For example, many hemlocks, spruces and firs stand out for being shade-tolerant and drought-intolerant. American hemlocks and firs have already been devastated by sapsucking insects called adelgids, and the authors believe these trees could be subject to future attacks. Making more specific predictions is among the group’s plans.

The scientists say their result could also help regulators prioritize limited resources available to protect forests from foreign pests.

The researchers “used the data we have in the best way it can be used to get at this problem,” said Lovett. But he noted that many destructive insects, such as the emerald ash borer, go after hardwood trees — a group that includes oaks, maples and elms — and the factors that predict the most destructive eaters of conifers may not apply to hardwoods.

Mech, Havill and their colleagues hope to report results on a companion study on hardwoods next year.

The current paper was published in Ecology and Evolution.

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Gabriel Popkin is a Washington, D.C.-area science writer who writes mainly about physics, ecology and environment.

 

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Using R. salonacearum on tomato plants as a test subject, this study has discovered why there is often spatial variation of plant diseases within a specific field (© Pexels)

A recent study has unearthed the mystery of how plant disease resistance is linked to the soil microbiome. This new area of research will open up new possibilities for a more sustainable food production system and help combat global food security threats.

Plant pathogens are a major threat to global food production, notably in food-deficit areas which can see up to 20-30% crop losses due to pathogens alone. There are numerous management practices and technologies aimed at reducing such losses, including the application of chemical control, breeding of resistant crop varieties and cultural control actions. However, all of these tools and systems are threatened by constantly evolving pathogen resistance, virulence levels and expanding host ranges due to changing climates.

A team of researchers from the University of York with colleagues from the Netherlands and China studied the effects of the soil microbiome on plant-pathogen interactions. It is commonly known that disease distributions vary across fields, but little is understood as to why this occurs rather than entire fields being equally affected by the same disease.

The study targeted bacteria wilt disease on tomato plants, caused by Ralstonia solanacearum. R. solanacearum is a major threat to global food production, with host crops including tomato, potato, pepper, bean and numerous weeds. The bacteria commonly infects crops via wounds in the root systems, leading to a number to internal symptoms such as necrotic vascular tissue which can be difficult to identify without damaging the plant. Other symptoms include leaf wilting and yellowing, necrotic leaf tissue and in severe cases, death of the host plant.

Dr Ville Friman from the Department of Biology at the University of York said “even though we have discovered that the pathogen is present everywhere in tomato fields, it is not capable of infecting all the plants. We wanted to understand if spatial variation could be explained by differences in soil bacterial communities.”

By targeting specific soil components, we may be able to improve plant health and yields by promoting beneficial bacteria (© Pexels)

The study involved sampling the soil of infected fields to compare the microorganisms that were present in the near vicinity of infected and healthy plants. The results of this showed that the microbiomes of plants which both survived infection and remained healthy were linked to specific pathogen-suppressing Pseudomonas and Bacillus bacteria.

“Our results show that it is important to focus not only on the pathogen but also the naturally-occurring beneficial microorganisms present in the rhizosphere. While the beneficial role of microbes for humans and plants have been acknowledged for a long time, it has been difficult to disentangle the cause and effect,” said Dr Friman.

The team are continuing their investigation, looking into the development of microbial inoculants to improve pathogen resistance in crop production. The findings of this study have shed light on the possibilities for the use of bacteria as ‘soil probiotics’, with the soil microbiome being a focus for crop management in the future.

By targeting the promotion of beneficial bacteria in the soil of fields, it may be possible to increase plant resistance to specific diseases using more natural tools such as organic fertilizers. In turn, this would reduce the need for intensive chemical treatments to control disease outbreaks as the negative effects of the plant pathogens existing in the soil would be reduced. The use of other non-invasive cultural management practices such as crop rotation and intercropping may be a useful IPM strategy with such soil inoculants to modify the soil composition in specific fields to promote crop-resistance.

If you would like to read more on the subject, please see the links below:

 

 

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Fungi could reduce reliance on fertilizers

Date:
October 24, 2019
Source:
University of Leeds
Summary:
 and could lead to new, ‘climate smart’ varieties of crops, according to a new study.
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Introducing fungi to wheat boosted their uptake of key nutrients and could lead to new, ‘climate smart’ varieties of crops, according to a new study.

Researchers at the University of Leeds have demonstrated a partnership between wheat and soil fungi that could be utilised to develop new food crops and farming systems which are less reliant on fertilisers, reducing their contribution to the escalating climate crisis.

It is the first time the fungi, which form partnerships with plant roots, have been shown to provide significant amounts of phosphorus and nitrogen to a cereal crop. The fungi continued to provide nutrients under higher levels of carbon dioxide (CO2) predicted for 2100, which has important implications for future food security.

The results were published today in the journal Global Change Biology.

Lead researcher Professor Katie Field, from the University of Leeds’ School of Biology and Global Food and Environment Institute, said: “Fungi could be a valuable new tool to help ensure future food security in the face of the climate and ecological crises.

“These fungi are not a silver bullet for improving productivity of food crops, but they have the potential to help reduce our current overreliance on agricultural fertilisers.”

Agriculture is a major contributor to global carbon emissions, partly due to significant inputs such as fertilisers. Whilst meat production contributes far more to global warming than growing crops, reducing the use of fertilisers can help lower agriculture’s overall contribution to climate change.

Ancient plant-fungi partnership

Most plants form partnerships with fungi in their root systems, known as arbuscular mycorrhizas, which enable them to draw nutrients from the soil more efficiently. In exchange, the plants provide carbohydrates to the fungi as a form of payment, known as a symbiosis.

Plants can give 10-20% of the carbon they draw from the air to their fungal partners, in exchange for up to 80% of their required phosphorus intake. These fungi can also help plants increase their growth, nitrogen levels, water uptake, and defend the plant against pests and disease.

But over the last 10,000 years, crop plants have been domesticated through intensive breeding, which has inadvertently stopped some varieties from having such close relationships with beneficial fungi.

Across the globe, wheat is a staple crop for billions, and wheat farming uses more land than any other food crop (218 million hectares in 2017). Despite increasing the application of nitrogen and phosphorus fertilisers to boost yields, the amount of wheat that can be produced from a given area has reached a plateau in recent years.

Whilst some varieties of the wheat grown by farmers form these partnerships with beneficial fungi, many do not. The Leeds researchers therefore suggest there is potential to develop new varieties of wheat that are less dependent on fertilisers.

Sustainable food production

Co-author Dr Tom Thirkell, from the University of Leeds’ School of Biology, said: “For thousands of years, farmers have been breeding crops to increase productivity and disease resistance, but this has mainly been based on what can be seen above ground.

“We are starting to realise that some of the crops we have domesticated lack these important connections with fungi in the soil. Our results suggest there is real potential to breed new crop varieties which regain this lost relationship with beneficial fungi, and improve the sustainability of future food production systems.”

Scientists allowed the fungi to colonise the roots of three different varieties of wheat in the laboratory and grew them in one of two chambers — either mimicking current climatic conditions or those projected for 2100, when CO2 concentration in the atmosphere is predicted to be double that of today if emissions are not curbed. They wanted to know what benefits the different varieties could gain from their fungal partners and how the relationships would be affected by increasing atmospheric CO2.

By chemically tagging phosphorus and nitrogen in the soil and CO2 in the air, the researchers were able to demonstrate that the different varieties of wheat absorbed the nutrients through their fungal partners, in both climate scenarios.

As expected, the three varieties of wheat underwent different levels of exchange with the fungi, with some varieties gaining much more from the relationship than others for a similar carbohydrate ‘cost’.

In particular, the Skyfall variety of wheat took up far more phosphorus from the fungi compared to the other two varieties, acquiring 570 times more than the Avalon variety and 225 times more than Cadenza.

There was no difference in phosphorus or nitrogen exchange from the fungi to the wheat at the higher CO2 level for any of the three crop varieties. It therefore appears that the fungi can continue to transfer nutrients to the crop even under future climate conditions.

The researchers suggest it could be possible to breed new varieties of wheat which are more accommodating to a fungal partnership. This could allow farmers to use less fertilisers, as it may allow the wheat to get more of its required nutrients through the fungi.

There is ongoing discussion about whether fungi are a net positive or negative to the growth of cereal crops, as some evidence suggests fungi can act as parasites to their plant hosts.

It has previously been predicted that higher CO2 levels in the atmosphere will lead to fungi taking more carbon from their plant hosts, but this study found that not to be the case for these three varieties of wheat.

The researchers recommend that field-scale experiments are now needed to understand whether the fungi’s beneficial effects on wheat demonstrated in this study are replicated in a farm setting.

This study was funded by the Biotechnology and Biological Sciences Research Council.

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Tomatoes Tim Hearden
Brown rugose fruit virus is a threat to tomato production.

‘Ebola of plant viruses’ concerns tomato industry

Brown rugose fruit virus found in Arizona, California.

Lee Allen | Aug 28, 2019

Virologists have brewed up a new alphabet soup — ToBRFV or tomato brown rugose fruit virus — and much to the consternation of greenhouse tomato growers in the U.S., it’s headed their way, already sending out advance scouts in Arizona and California.

First discovered in Jordan in 2015, it moved on to Israel, Turkey, and Saudi Arabia, was spotted in Germany (2016) and Italy (2018) with likely occurrences reported  (but not confirmed) in Chile, Ethopia, Sudan, Thailand, Peru, China, and the Netherlands.  Now it’s being reported as widespread in Mexican greenhouses, just a hop and a skip across the border into neighboring states.

“We’ve had two incidents of it in California,” says Bob Gilbertson, who specializes in plant virology and seed pathology at University of California, Davis.  “It was identified in a Santa Barbara County production greenhouse in September last year, confirmed by Kai-Shu Ling of the U.S. Department of Agriculture and by our plant pathologists.  In that instance, all ToBRFV-infested and symptomatic plant material was voluntarily destroyed.

“Then, sometime in early August, we received suspect fruits from a market in Sacramento that had obtained them from Baja, Mexico,” he said.  According to a report by Gilbertson and Zach Bagley of the California Tomato Research Institute, “They didn’t have necrotic lesions on the fruit — there were white blotches — but when we tested them, ToBRFV showed up.”

The acronym for tomato brown rugose fruit virus represents a new species of a well-known group of plant viruses, tobamoviruses.  It’s highly virulent and seems to override existing genetic controls and researchers are noting: “Because of the rapid spread of this virus, it represents a major concern for worldwide tomato production because no tomato varieties are known to be resistant to it as it breaks or is not recognized by Tm-2 2 or any other resistance gene currently used to protect tomatoes genetically against tobamoviruses.”

GREENHOUSES AFFECTED

Available information to date suggests ToBRFV is primarily a threat to protected culture (greenhouse or screenhouse) production although outbreaks in open fields have been reported in Mexico.

Because they grow more than 90 percent of the nation’s processed tomatoes but don’t grow for the fresh market, the California Tomato Growers Association is keeping a watchful eye on the situation, but suggests the greater concern belongs to the Western Growers Association.

Asked for comment, WGA’s Communications Manager Stephanie Metzinger replied by e-mail: “While we are aware of the situation, we do not have a statement to provide.”

One of WGA’s larger growers, Houweling’s in Camarillo, CA — with 125 acres under glass and additional production facilities in Utah and Canada — was willing to comment.

In a statement to Western Farm Press, they reported, “We’ve been diligent since the rumors and early news of ToBRFV, reassessing all our phytosanitary and operating protocols.  We’ve eliminated packing products from other sites and opened satellite packing operations to manage partner grower products.  Empty trucks get disinfected and cleaned, and in cooperation with our partners, we have eliminated the use of RPC shippers which we identified as a significant risk.”

‘EBOLA OF PLANT VIRUSES’

“We’re calling this one The Ebola of Plant Viruses,” says Gilbertson, first cautioning, “you’ve got to be vigilant about it because it spreads so rapidly,” and then cajoling, “but growers shouldn’t be paranoid and panicking because we have a number of ways to manage it.”

Because Arizona is a major hub of tomatoes imported into the U.S., it could be a bellweather for California growers and Gilbertson suggests everybody needs to be on heightened awareness.

Already recognizing that the best defense is a good offense, Wholesum Farms (Wholesum Harvest) with tomato greenhouses in Arizona as well as Sonora and Sinaloa, Mexico, is on alert with their beefsteak, cherry, Roma, and tomatoes-on-the-vine production.

“ToBRFV is a very serious threat to our production and we’re taking all necessary steps to insure we remain virus-free,” says Theojary Crisantes, Chief Operations Officer of the company with 60 acres of greenhouses, 220 acres of protected fields, and 325 acres of open field production who partner with other family-owned and -operated organic growers from Central Mexico through California.

“There has been no detected presence of the virus in any of our operations in Mexico or the USA and we’re taking extreme measures in sanitation going in and out of our greenhouses to make sure things stay that way.”

SYMPTOM SPOTTED

Not so lucky is the nearby NatureSweet operation that maintains 500 hectares in Mexico and 120 hectares in Arizona, with an annual production of 18 million plants, all under glass.

“We found rugose in one of our greenhouses in March of this year,” says General Manager Alexandro Briones Sanchez. “We spotted it from the first symptom and took immediate action, removing that row and five rows on either side and burning the plants and the coconut coir before performing a complete sanitizing.

“Some companies, when they find the first symptom, they’ll take a plant sample and send it to analysis which could take 48-72 hours.  Because the virus is spread mechanically, by that time you may have touched all of your greenhouses if you’re not segregated and share labor.  From our experience, if you make your decisions immediately when you find a plant with viral symptoms and remove it, it will be controllable at that point and pay off in the long run.”

Pathologist Gilbertson emphasizes the speed of the spread factor.  “There is no insect vector here.  It’s solely transmitted by contact, human touch or machines or tools.  It’s extremely stable and can survive in dry tissue for years.”

Diagnostic seed testing is one of the keys to slowing down the spread of the virus, he says, advocating, “Management before, during, and after the growing season.”  After the seed is tested, implement the safety factor, Plan B, which is to treat that seed with a 10% triple sodium phosphate solution “which will virtually eradicate any virus in the seed.”

GET THEM OUT EARLY

That’s what you can do before planting.  During the growing season, constantly walk the rows looking for any kind of mosaic, a mottling on the leaves that will sometimes elongate.  “Get those plants out early and don’t let them touch other plants to minimize the amount of inoculum.  Workers need to be wearing clean protective clothing and dip their gloves and tools in TSP.”

After the growing season — “Remove all the plants and spray down the inside of the house…all the benches, strings, ropes, tools, everything.  This kind of sanitation is practiced in protected culture for bacterial canker, but the possibility of ToBRFV requires even more vigilance and intense sanitation.”

Gilbertson offers the following: “Although growers may have to spend more on sanitation protocol, this virus is hardly going to threaten tomato production in the U.S., protected or open-field.  And although we have to up our game a bit, it shouldn’t cause a panic because we have a number of ways to manage it.”

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PHYS ORG

Next-generation sequencing used to identify cotton blue disease in the United States

Next-generation sequencing used to identify cotton blue disease in the United States
An example of one of the slides in the “Focus on Cotton” webcast about Cotton Blue Disease. Credit: Plant Management Network and Judith K. Brown

Cotton blue disease, caused by Cotton leafroll dwarf virus (CLRDV), was first reported in 1949 in the Central African Republic and then not again until 2005, when it was reported from Brazil. In 2017, cotton blue disease was identified in Alabama, marking the first report in the United States.

Plant pathologists discovered foliar distortion and leaf curling and rolling on cotton in six counties in coastal Alabama. They sent samples to University of Arizona plant pathologist Judith K. Brown, who originally suspected the causal agent to be a whitefly-transmitted geminivirus—the only type of virus known to infect cotton in the United States at that time. However, after using the Illumina platform for discovery genomics to conduct next-generation sequencing, Brown determined that the symptoms were characteristic of cotton blue .

Characteristic symptoms of cotton blue disease include slowed plant growth and loss of chlorophyll, causing the yellowing or dwarfing of infected leaves and/or the entire plant. The disease also inhibits translocation and results in reddening due to nutrient deficiencies. Symptoms usually do not appear until after full bloom in late August.

To learn more about for the disease, Brown researched the used in Brazil. There, strategies focus on eliminating the reservoir host with weed control and preventing volunteer cotton ; the latter is not a problem in Alabama, where the ground freezes. In Brazil, chemicals are used to control the insects that transfer the disease to the cotton, but this is not an option in the United States. There is currently no recommended course of management for cotton blue disease. Additional research is needed to determine effective management strategies. Brown encourages researchers to focus on genetic resistance.

The full story behind the discovery of cotton blue disease in Alabama is presented in two “Focus on Cotton” webcasts: the 33-minute “Introduction of Cotton leaf roll dwarf-like Polerovirus into the United States: High-Throughput Discovery, Identification, and Genomic Comparisons,” by Judith K. Brown, and the 13-minute “Cotton Blue Disease Caused by Cotton leafroll dwarf like virus: Identification, Symptomology, and Occurrence in Alabama,” by Kathy S. Lawrence.

Both presentations are available through the “Focus on Cotton” resource on the Plant Management Network. This resource contains more than 75 webcasts, along with presentations from six conferences, on a broad range of aspects of cotton crop management: agronomic practices, diseases, harvest and ginning, insects, irrigation, nematodes, precision agriculture, soil health and crop fertility, and weeds. These webcasts are available to readers (without a subscription).

The “Focus on Cotton” homepage also provides access to “Cotton Cultivated,” a new resource from Cotton Incorporated that helps users quickly find the most current production information available. These and other resources are freely available courtesy of Cotton Incorporated at http://www.plantmanagementnetwork.org/foco.


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First report of cotton blue disease in the United States

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