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Water beetles can live on after being eaten and excreted by a frog

One insect crawled through the amphibian’s insides in just six minutes

Pond frog
This pond frog (Pelophylax nigromaculatus) makes easy prey of water beetles. But one beetle species (Regimbartia attenuate) can escape predation by traversing the amphibian’s digestive tract and emerge, still kicking, out the other end.SHENJI SUGIURA

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By Jonathan Lambert

AUGUST 3, 2020 AT 11:00 AM

For most insects, the sticky, slingshot ride straight into a frog’s mouth spells the end. But not for one stubborn water beetle.

Instead of succumbing to the frog’s digestive juices, an eaten Regimbartia attenuata traverses the amphibian’s throat, swims through the stomach, slides along the intestines and climbs out the frog’s butt, alive and well.

“This is legitimately the first article in a while that made me say, ‘Huh! How weird!’” says Crystal Maier, an entomologist at Harvard University’s Museum of Comparative Zoology. “There are still a lot of truly bizarre habits of insects that still wait to be discovered,” she says.

Surviving digestion-by-predator is rare, but not unheard of in the animal kingdom. Some snails survive the trip through fish and birds by sealing their shells and waiting it out. But research published August 3 in Current Biology is the first to document prey actively escaping through the backside of a predator.

Feeding beetles to predators to see what happens is a regular activity for Shinji Sugiura, an ecologist at Kobe University in Japan. In 2018, he discovered that bombardier beetles can force toads to vomit the insects back up by releasing a mix of hot, noxious chemicals from their rear ends (SN: 2/6/18). 

On a hunch that R. attenuata might have evolved its own interesting evasive behaviors, Sugiura paired a beetle with a frog that the insect often encounters while swimming through Japanese rice paddies. In his laboratory, he watched.

The frog made easy prey of the unsuspecting beetle. While the amphibians lack teeth that could kill prey with a crunch, a trip through the acidic, oxygen-poor digestive system should be sufficient to neutralize the insect. But as Sugiura monitored the frog, he saw the shiny black beetle slip out from the frog’s behind and scurry away, seemingly unharmed.https://www.youtube.com/embed/_W0UJD_i3Mo?feature=oembed&enablejsapi=1&origin=https:%2F%2Fwww.sciencenews.orgAbout two hours before this video begins, this pond frog (Pelophylax nigromaculatus) ate a water beetle (Regimbartia attenuata). After traversing the digestive tract, the beetle emerges from the back end of the amphibian, alive. It’s the first documented example of prey actively escaping a predator through the digestive system.

“I was very surprised,” he says. “I was expecting that the frogs might just spit out the beetles or something.”

After more than 30 additional beetle-frog pairings, Sugiura found that over 90 percent of beetles survived being eaten, greatly outshining other animals known to survive digestion-by-predator. Those creatures typically survive less than 20 percent of the time. On average, it took six hours for the beetles to escape, though one intrepid individual completed the journey in just six minutes. 

Sugiura confirmed that the beetles were actively escaping from the frog’s digestive tract by using sticky wax to fix some beetles’ legs together. None of these immobilized beetles survived, and their carcasses took a day or longer to pass through the frogs.

R. attenuata’s aquatic lifestyle likely prepared the beetle to survive digestion, Sugiura says. Its streamlined, but sturdy, exoskeleton may shield the insect from digestive juices. And its ability to breath underwater via air pockets tucked under its hardened wings likely prevents suffocation.

Sugiura plans to test the limits of R. attenuata’s abilities by pairing the insect with larger frogs, toads and even fish. “I’m looking forward to finding unimaginable types of antipredator defense,” he says.

Questions or comments on this article? E-mail us at feedback@sciencenews.org

CITATIONS

S. Sugiura. Active escape of prey from predator vent via the digestive tractCurrent Biology. Published online August 3, 2020. doi: 10.1016/j. cub.2020.06.026.

S. Wada, K. Kawakami and S. Chiba. Snails can survive passage through a bird’s digestive systemJournal of Biogeography. Vol. 39, January 2012, p. 69. doi: 10.1111/j.1365-2699.2011.02559.x.

R.J. Brown. Freshwater mollusks survive fish gut passageArctic. Vol. 60, June 2007, p.  124. http://www.jstor.org/stable/40513128.

About Jonathan Lambert

Jonathan Lambert is the staff writer for biological sciences, covering everything from the origin of species to microbial ecology. He has a master’s degree in evolutionary biology from Cornell University.

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August 4, 2020

Sara Hendery

Integrated pest management practices bring more than $12 billion to the developing world

This article was originally published by Virginia Tech Daily

The implementation of IPM practices for onions in the Philippines generated $23.5 million in economic benefits for the country, according to recent findings by Virginia Tech and ICIPE researchers.

The implementation of integrated pest management strategies is improving livelihoods and bringing billions of dollars in economic benefits to developing nations.

That’s according to findings of a review published recently by Virginia Tech researchers George Norton, Muni Muniappan, and Jeff Alwang and researcher Menale Kassie from the International Centre of Insect Physiology and Ecology in Kenya. Together they document more than $12 billion in economic benefits as a result of integrated pest management application, which more than pays for all the funds spent globally on IPM.

The research is a compilation of case studies in Asia, Africa, Latin America, and the Caribbean that contest the long-held assumption that IPM does not contribute substantial economic benefits to the developing world. Discovering such high economic returns has important implications for nations searching for a pathway out of poverty and food insecurity.

“The assumption that IPM, or ecological practices more generally, are not suitable for the developing country context stems from a lack of information,” said George Norton, a professor in the Department of Agricultural and Applied Economics in the College of Agriculture and Life Sciences. “This study provides information to demonstrate that IPM can generate major economic benefits, especially when targeted at particular pests.”

IPM involves the introduction of a combination of agricultural practices to manage pest and disease problems. It grew out of the desire to minimize the overuse of synthetic pesticides. Many believe IPM is less suitable for developing countries, given their often-limited access to resources. However, at the core of IPM is allowing farmers to select certain crop practices — including pruning, using insect traps to monitor pest spread, biocontrol, the application of bio-pesticides, and more — that are most appropriate for their social, economic, and environmental conditions.

The findings appear in a chapter in “The Economics of Integrated Pest Management of Insects,” edited by David Onstad and Philip Crain. It highlights not only IPM success stories, but also economic analysis more generally as a critical decision-making tool for effective crop management.

Virginia Tech’s Feed the Future Innovation Lab for Integrated Pest Management has implemented sustainable, IPM-based strategies in the developing world for over a quarter of a century. Some of the program’s economic impacts are documented in the chapter’s case studies, including the program’s implementation of biocontrol to manage the papaya mealybug in India in 2014, which brought up to $1.4 billion in economic benefits to the country.

“The implementation of sustainable technologies isn’t just beneficial for the environment,” said Muniappan, director of the IPM Innovation Lab. “Rather than providing just one pathway to producing healthy plants, IPM offers many that farmers can choose from, which is helpful for communities whose access to economic resources is often changing.”

(From left) George Norton, Muni Muniappan, and collaborator Yousuf Mian in Bangladesh.

Other case studies of IPM practices with high economic returns were highlighted in the chapter:

– Biocontrol of the cassava mealybug in sub-Saharan Africa — $9 billion in economic benefits.

– Biocontrol of the maize stemborer in Kenya, Mozambique, and Zambia — $272 million.

– Introduction of virus-resistant groundnuts in Uganda — $62 million.

– IPM for onion in the Philippines — $23.5 million.

– IPM for eggplant and cabbage in Bangladesh — $29 million.

The case studies also document impacts from IPM adoption such as increased yields, reduced poverty and pesticide costs, and environmental benefits. In 2018, for example, a case study in Kenya shows an IPM intercropping technique helped raise at least 75,000 people above the poverty line. In Ecuador, in 2016, IPM practices used for the citrus-flavored fruit naranjilla reduced deforestation costs by an estimated $3.67 million.

“It’s not just about feeding more people,” added Muniappan about the value of the research. “It’s about improving overall livelihoods.”

Norton has collaborated with the IPM Innovation Lab since the program’s inception in 1993. Both Alwang, also a professor in the Department of Agricultural and Applied Economics, and Kassie, head of the Social Science and Impact Assessment Unit at ICIPE, have in the past or are currently collaborating with the IPM Innovation Lab.

The IPM Innovation Lab is funded by the U.S. Agency for International Development and housed at the Center for International Research, Education, and Development, part of Outreach and International Affairs.

This article was originally published by Virginia Tech Daily


The Economics of Integrated Pest Management of Insects is available from the CABI Bookshop.

The findings presented in this article are from chapter 8: Economic Impacts of Integrated Pest Management Practices in Developing Countries.IPMIntegrated Pest managementeconomic impacteconomicsinsect pestsAgriculture and International DevelopmentDevelopment communication and extension


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Would you give up yield to boost natural defenses?

The main thing driving the industry is yield.

John Hart | Jul 30, 2020

Plants bred to yield better often lose their natural defenses to battle insects, and the question arises would farmers be willing to turn to plant varieties that may yield less but can better defend themselves against insects, lessening the need for insecticides.

In a July 22 virtual forum sponsored by the North Carolina Biotechnology Center,  Jeremy Kroemer, agrochemical discovery lead for Bayer Crop Science; and Joseph Stout,  BASF  group leader, biology, global insecticide research advanced biology and agronomy, said this will be a tough sell because yield is still the name of the game. https://tpc.googlesyndication.com/safeframe/1-0-37/html/container.html

“The main thing driving the industry is yield. At the end of the day, the farmer wants a product that works, the farmer wants a product that’s going to bring home the maximum yield,” Kroemer emphasized in the forum for crop scientists.

By and large, Kromer said farmers want clean fields, free of worrisome weeds and insects. He notes that the introduction of Bt (Bacillus thuringiensis) hybrids that are resistant to insects has grown the viewpoint that a clean field is not being impacted by insect damage.

Kroemer says plants with a natural defense to insects will still be touched by and eaten to some extent by insects which will concern farmers looking to improve yields. He says farmers look for visual cues and if they see insect damage, they want to control that damage because the seek to protect the plant entirely.

Kromer says engineered traits that push insects away from the plant and enhance the survivability of plants would interest farmers.

“Let’s say you engineer a plant to be more resistant to insect damage. You  add in a trait that causes a feeding deterrent and pushes the animal away and then you retain  your stacks of Bt that actually kill the insects. In this  case you may be providing a new situation where you are pushing certain animals in the population away from that plant and you’re providing a selective advantage for those animals because they’re not being killed by the Bt  that’s retained by the plant,”  Kroemer said.

Stout agrees with Kromer and says it all comes down to economics. He says farmers want to control pests, but they also want to reduce insecticide costs. If it is more cost effective to use genetically engineered seed and thereby reduce insecticide costs, farmers will likely go that route.

 “There are different insecticides out there.  Some of them have a more benign profile to non-target insects. There  is some selectivity in some of those. A putative  neurotoxin causes paralysis and within a matter of minutes the insect is dead. You  also have insecticides that inhibit feeding,” Stout said.

Stout said the benefits must be demonstrated in a competitive way. For example, the pest may still be present in the field, but the damage caused to the crop is reduced.  Still, anything that reduces yield and quality will be a difficult sell.

“A big part is the expectation of the end of the end user. There is consumer demand for zero pest presence. That’s an even more difficult sell. For example, head lettuce and table grapes are crops that need to be pristine,” he said.TAGS: INSECTSSOYBEANSINSECTS

Bug wars: Feds introduce Asian wasps to battle emerald ash borer outbreak in Lincoln area

Ash borer wasps

The Tetrastichus planipennisi wasp lays eggs in the larvae of the emerald ash borer.

  • Peter Salter

A piece of ash branch, infested with the emerald ash borer and injected with the eggs of the Tetrastichus planipennisi wasp, was attached to an ash tree at Platte River State Park last summer.

City tree crews discovered the first signs of emerald ash borer infestation in a tree near 37th and F streets.

One of the newest members of Lincoln’s insect family is a little wasp with a big name and no desire for human flesh.

But it can’t live without the emerald ash borer.

The Tetrastichus planipennisi is an underhanded killer, penetrating the bark of an infected ash tree with its ovipositor — the stinger on other species — to lay eggs in the larvae of the emerald ash borer.

“Then the eggs hatch,” said Dave Olson, a forest health specialist with the Nebraska Forest Service. “And they eat the ash borer from the inside-out.”

Its cousin, Oobius agrili, likes its borers even younger: It injects its own egg inside an ash borer egg, eventually hatching, growing and killing its host.

In both cases, the parasitic wasps mature — larvae, pupae, adulthood — then fly away, looking for more victims, continuing the cycle.

 Ash borer update: Some trees to get reprieve; replanting plans not taking root everywhere

And the brutality of this bug-eat-bug world is now being waged in Lincoln and nearby state parks, introduced to the area by the U.S. Department of Agriculture in an attempt to slow the spread of the emerald ash borer.

The Asian beetle, about the size of a cooked grain of rice, was first confirmed in North America in the early 2000s and has been eating its way west across the U.S. since, piling up massive damage.ADVERTISING

The insect had already killed tens of millions of ash trees — with an estimated value of $11 million — by the time it reached Nebraska, first confirmed in a Douglas County tree in 2016. It landed in Lancaster County in 2018, caught in a trap near Pioneers Park, and was discovered infesting trees in Lincoln last spring.

It’s a lethal little bug, and Lincoln’s estimated 65,000 public and private ash trees are vulnerable. The city has already started removing and replacing most of its 14,000 trees from parks, golf courses and along streets, and will attempt to prolong the lives of some with chemical treatments.

 Emerald ash borer found in Nebraska’s Saunders County

The stingless wasps were the federal government’s idea. The USDA’s Plant Protection and Quarantine program approached the state last year, and the Forest Service identified a handful of spots that could benefit from biocontrol: Pioneers Park, Mahoney and Platte River state parks and Fremont Lakes State Recreation Area.

A federal rearing lab in Michigan supplied nearly 20,000 wasps from three species and in various stages — Oobius agrili pupae, Tetrastichus planipennisi eggs, larvae and pupae, and Spathius galinae wasps.

In some cases, the lab delivers a Trojan tree limb — a branch cutting already infested with ash borer and injected with wasp larvae. Once in the field, the branch is attached to a tree that shows signs of the ash borer, and the adult wasps emerge from the cutting and start hunting in the host tree.

It’s too soon to see results, Shayne Galford, the USDA’s state plant health director for Nebraska and Kansas, said in an email. But officials will return to the release sites to introduce more wasps this year, and check for established populations in 2021. They could also add more sites, he said.

 ‘Each table is a small victory’ — How volunteers and salvage lumber are helping flood victims

The new weapon in the war on emerald ash borers won’t stop their spread, said Olson, with the state forest service. But it could crimp it.

“It’s not going to be a silver bullet. The real goal is to get these predators set up so in a few years the emerald ash borer has additional pressure on it.”

 In war against ash borer, a side skirmish erupts in east Lincoln

Reach the writer at 402-473-7254 or psalter@journalstar.com.

On Twitter @LJSPeterSalter View Comments84215

How to get ready for the emerald ash borer in the Lincoln area

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How to get ready for the emerald ash borer in the Lincoln area

  • Updated Feb 18, 2020

They found the first bug in August, in a treetop trap they set northwest of Pioneers Park.

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Smithsonian Takes a Look at the World’s Most Interesting Insects

By Jessica Stewart on July 20, 2020

  • My Modern Net

Representing 80% of all animal species, insects are some of the most abundant animals on Earth. And yet, there is so much that your average person doesn’t know about these fascinating creatures. Thankfully, Smithsonian has taken it upon itself to highlight some of the most fascinating examples of these colorful animals with the Smithsonian Handbook of Interesting Insects.

Each insect was selected from the 34 million specimens located in London’s Natural History Museum. Over one hundred of the most significant bugs were chosen to get a full photographic layout accompanied by a short description. The book was curated by entomologists Gavin Broad, Blanca Huertas, Ashley Kirk-Spriggs, and Dmitry Telnov, who worked tirelessly to showcase a wide range of interesting insects.

“Our hope is that by drawing attention to some of the amazing variety of insect life, people will appreciate a bit more the explosion of color and form at the tiny scale,” shares Gavin Broad, who is the principal curator in charge of insects at the Natural History Museum. “And that acting to conserve the natural world will help ensure this diversity of life continues to thrive forever, rather than only being known from old museum specimens.”

Selections include the Claudina butterfly, whose crimson wings are beautiful in their own right but are nothing compared to the surprise of its underwings. Splashed with bright fuchsia and violet patches, this explosion of color is complemented by yellow tufts called the androconia. These are used to release pheromones that become vital in courtship.

Color is also on display when looking at a large African insect known as the Green milkweed grasshopper. Its rainbow-hued hind wings are typically hidden away when at rest, but are used when needed to scare off predators. And beware, when startled, it releases a  noxious fluid from its thorax that is derived from the poisonous plants it feeds on.

These are just some of the wasps, moths, beetles, and butterflies that are included in the Smithsonian guide. Filled with scientific information, but written to be accessible, it’s the perfect book for any insect lover.

Smithsonian Handbook of Interesting Insects is a guide to the world’s most fascinating bugs.

Claudina Butterfly

Claudina ButterflyPapuan Green Weevil

Papuan Green Weevilhttps://e9ce1564218607c73b1cc5d041a9f7d6.safeframe.googlesyndication.com/safeframe/1-0-37/html/container.htmlOrchid Cuckoo Bee

Orchid Cuckoo BeeFlatid Planthopper

Flatid Planthopperhttps://e9ce1564218607c73b1cc5d041a9f7d6.safeframe.googlesyndication.com/safeframe/1-0-37/html/container.htmlBrazilian Jewel Beetle and Darkling Beetle

Left: Brazilian Jewel Beetle | Right: Darkling Beetle

All images via the London Natural History Museum. My Modern Met granted permission to feature photos by Smithsonian Books.

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JESSICA STEWART

Jessica Stewart is a Contributing Writer and Digital Media Specialist for My Modern Met, as well as a curator and art historian. She earned her MA in Renaissance Studies from University College London and now lives in Rome, Italy. She cultivated expertise in street art which led to the purchase of her photographic archive by the Treccani Italian Encyclopedia in 2014. When she’s not spending time with her three dogs, she also manages the studio of a successful street artist. In 2013, she authored the book ‘Street Art Stories Roma‘ and most recently contributed to ‘Crossroads: A Glimpse Into the Life of Alice Pasquini‘. You can follow her adventures online at @romephotoblog.Read all posts from Jessica StewartFASCINATED BY BUGS?  SHARELIKE MY MODERN MET ON FACEBOOK https://www.facebook.com/v2.6/plugins/like.php?action=like&app_id=127840663940988&channel=https%3A%2F%2Fstaticxx.facebook.com%2Fx%2Fconnect%2Fxd_arbiter%2F%3Fversion%3D46%23cb%3Df288e6c3345f668%26domain%3Dmymodernmet.com%26origin%3Dhttps%253A%252F%252Fmymodernmet.com%252Ff27d6f080cd4da8%26relation%3Dparent.parent&container_width=555&href=https%3A%2F%2Fwww.facebook.com%2Fmymodernmet%2F&layout=button_count&locale=en_US&sdk=joey&share=true&show_faces=false GET OUR WEEKLY NEWSLETTER


JULY 20, 2020

Returning to farming’s roots in the battle against the ‘billion-dollar beetle’

by University of Arizona

Returning to farming's roots in the battle against the 'billion-dollar beetle'
Western corn rootworm larvae can devour the tips of corn roots, robbing the plants of nutrients and making them susceptible to falling over. Credit: Cyril Hertz, Lingfei Hu and Matthias Erb, University of Bern, Switzerland

Nicknamed the “billion-dollar beetle” for its enormous economic costs to growers in the United States each year, the western corn rootworm is one of the most devastating pests farmers face.https://3777ec3032f89ac36b1a5fe5c7568749.safeframe.googlesyndication.com/safeframe/1-0-37/html/container.html

“They are quite insidious. They’re in the soil gnawing away at the roots and cutting off the terminal ends of the roots—the lifeblood of corn,” said Bruce Tabashnik, Regents Professor and head of the University of Arizona Department of Entomology. “And if they’re damaging enough, the corn plants actually fall over.”

Genetically modified crops have been an important tool in the battle against pests such as these, increasing yields while reducing farmers’ reliance on broad-spectrum insecticides that can be harmful to people and the environment.

Corn was genetically engineered to produce proteins from the bacterium Bacillus thuringiensis, or Bt, that kill rootworm larvae but are not toxic to humans or wildlife. The technology was introduced in 2003 and has helped keep the corn rootworm at bay, but the pest has begun to evolve resistance.

“So, now the efficacy of this technology is threatened and if farmers were to lose Bt corn, the western corn rootworm would become a billion-dollar pest again,” said Yves Carrière, a professor of entomology in the College of Agriculture and Life Sciences.

Crop Rotation in Mitigating Pest Resistance

Carrière is lead author of a study to be published in PNAS that evaluated the effectiveness of crop rotation in mitigating the damage caused by resistant corn rootworms. Tabashnik and colleagues from North Carolina State University, the University of California-Davis, McGill University and Stockholm University coauthored the study.

Crop rotation, the practice of growing different crops in the same field across seasons, has long been used for pest control. In 2016, the U.S. Environmental Protection Agency mandated crop rotation as a primary means of reducing the damage to Bt corn fields caused by resistant corn rootworms, but there have been limited scientific studies to support the efficacy of this tactic.https://googleads.g.doubleclick.net/pagead/ads?client=ca-pub-0536483524803400&output=html&h=280&slotname=5350699939&adk=2265749427&adf=625945176&w=750&fwrn=4&fwrnh=100&lmt=1595996918&rafmt=1&psa=1&guci=2.2.0.0.2.2.0.0&format=750×280&url=https%3A%2F%2Fphys.org%2Fnews%2F2020-07-farming-roots-billion-dollar-beetle.html&flash=0&fwr=0&rpe=1&resp_fmts=3&wgl=1&dt=1595996918602&bpp=11&bdt=88&idt=147&shv=r20200727&cbv=r20190131&ptt=9&saldr=aa&abxe=1&cookie=ID%3Dfd49ee1f356c7aad-2230268791c20026%3AT%3D1595996908%3AS%3DALNI_MZ__AIkhsEMsw1AjrlZUCXlh_wvFw&correlator=2622896222429&frm=20&pv=2&ga_vid=683244895.1595996911&ga_sid=1595996919&ga_hid=1573871060&ga_fc=0&iag=0&icsg=2271232&dssz=26&mdo=0&mso=0&u_tz=-300&u_his=2&u_java=0&u_h=1080&u_w=1920&u_ah=1040&u_aw=1920&u_cd=24&u_nplug=3&u_nmime=4&adx=447&ady=2184&biw=1903&bih=969&scr_x=0&scr_y=0&oid=3&pvsid=1003068873479674&pem=0&rx=0&eae=0&fc=896&brdim=0%2C0%2C0%2C0%2C1920%2C0%2C1920%2C1040%2C1920%2C969&vis=1&rsz=%7C%7CpeEbr%7C&abl=CS&pfx=0&fu=8320&bc=31&ifi=1&uci=a!1&btvi=1&fsb=1&xpc=7ptrOeJu1R&p=https%3A//phys.org&dtd=154

Carrière and his team rigorously tested this approach by analyzing six years of field data from 25 crop reporting districts in Illinois, Iowa and Minnesota—three states facing some of the most severe rootworm damage to Bt cornfields.

The results show that rotation works. By cycling different types of Bt corn and rotating corn with other crops, farmers greatly reduced rootworm damage.

Most notably, crop rotation was effective even in areas of Illinois and Iowa where rootworm resistance to corn and soybean rotation had been previously reported.

According to the study, crop rotation provides several other benefits as well, including increased yield, reductions in fertilizer use and better pest control across the board.

“Farmers have to diversify their Bt crops and rotate,” Carrière said. “Diversify the landscape and the use of pest control methods. No one technology is the silver bullet.”

Returning to farming's roots in the battle against the 'billion-dollar beetle'
Western corn rootworm beetle on corn tassels. Credit: Joseph L. Spencer, Illinois Natural History Survey, University of Illinois at Urbana-Champaign

A Multipronged Approach

Tabashnik relates the research back to UArizona’s work with the pink bollworm, in which researchers spearheaded a management program to suppress the pink bollworm’s resistance to Bt cotton.

“The key to eradicating pink bollworm in the U.S. was integrating Bt cotton with other control tactics,” Tabashnik said. “We succeeded, whereas this voracious invasive pest rapidly evolved resistance to Bt cotton in India, where the genetically engineered crop was used alone.”

In collaboration with cotton growers, UArizona scientists sustained the efficacy of Bt cotton against pink bollworm by establishing the “refuge strategy,” in which non-Bt crops are planted near Bt crops to allow survival of susceptible insects. The strategy has become the primary approach used worldwide to delay the adaptation of insect pests to genetically engineered crops.

Although farmers have used refuges to thwart the rootworm’s resistance to Bt corn, this strategy alone has proven insufficient against the pest.

“During the last decade, we have learned that refuges are often not sufficient to delay resistance in pests like the corn rootworm,” Carrière said. “It would be wise to diversify management tactics before such pests evolve resistance. This approach, called integrated pest management, is vital for preserving the benefits of biotechnology.”

Returning to Agricultural Roots

In many ways, the study reaffirms traditional agricultural knowledge.

“People have been rotating crops since the dawn of farming. The new agricultural technology we develop can only be sustained if we put it in the context of things we’ve known for thousands of years,” Tabashnik said. “If we just put it out there and forget what we’ve learned in terms of rotating crops, it won’t last.”

The authors emphasize that increasing crop rotation is essential for sustaining the economic and environmental benefits provided by rootworm-active Bt corn. During the six years of the study, the average percentage of corn rotated to other crops per state ranged from about 55-75%.

“This is one of the most important applications of Bt crops in the United States,” Carrière said. “If we lose this technology and we start using soil insecticides again, it’s going to have a big negative environmental impact.”


Explore furtherScientists offer recommendations for delaying resistance to Bt corn in western corn rootworm


More information: Crop rotation mitigates impacts of corn rootworm resistance to transgenic Bt corn, PNAS (2020). DOI: 10.1073/pnas.2003604117Journal information:Proceedings of the National Academy of SciencesProvided by University of Arizona

Tree pest detection

NEWS RELEASE 20-JUL-2020

Portable DNA device can detect tree pests in under two hours

New method tests for harmful species like the Asian gypsy moth and sudden oak death pathogen

UNIVERSITY OF BRITISH COLUMBIASHARE PRINT E-MAIL

IMAGE
IMAGE: UBC PROFESSOR RICHARD HAMELIN INSPECTING A GYPSY MOTH TRAP view more CREDIT: PAUL H JOSEPH/UBC

Asian gypsy moths feed on a wide range of important plants and trees. White pine blister rust can kill young trees in only a couple of years. But it’s not always easy to detect the presence of these destructive species just by looking at spots and bumps on a tree, or on the exterior of a cargo ship.

Now a new rapid DNA detection method developed at the University of British Columbia can identify these pests and pathogens in less than two hours, without using complicated processes or chemicals – a substantial time savings compared to the several days it currently takes to send samples to a lab for testing.

“Sometimes, a spot is just a spot,” explains forestry professor Richard Hamelin, who designed the system with collaborators from UBC, Natural Resources Canada and the Canadian Food Inspection Agency. “Other times, it’s a deadly fungus or an exotic bug that has hitched a ride on a shipping container and has the potential to decimate local parks, forests and farms. So you want to know as soon as possible what you’re looking at, so that you can collect more samples to assess the extent of the invasion or begin to formulate a plan of action.”

Hamelin’s research focuses on using genomics to design better detection and monitoring methods for invasive pests and pathogens that threaten forests. For almost 25 years, he’s been looking for a fast, accurate, inexpensive DNA test that can be performed even in places, like forests, without fast Internet or steady power supply.

He may have found it. The method, demonstrated in a preview last year for forestry policymakers in Ottawa, is straightforward. Tiny samples like parts of leaves or branches, or insect parts like wings and antennae, are dropped into a tube and popped into a small, battery-powered device (the Franklin thermo cycler, made by Philadelphia-based Biomeme). The device checks to see if these DNA fragments match the genomic material of the target species and generates a signal that can be visualized on a paired smartphone.

“With this system, we can tell with nearly 100 per cent accuracy if it is a match or not, if we’re looking at a threatening invasive species or one that’s benign,” said Hamelin. “We can analyze up to nine samples from the same or different species at a time, and it’s all lightweight enough–the thermocycler weighs only 1.3 kilos–to fit into your backpack with room to spare.”

The method relies on PCR testing, the method that is currently also the gold standard for COVID-19. PCR testing effectively analyzes even tiny amounts of DNA by amplifying (through applying heating and cooling cycles) a portion of the genetic material to a level where it can be detected.

Hamelin’s research was supported by Genome Canada, Genome BC and Genome Quebec and published in PLOS One. The UBC team, including lead author Arnaud Capron, tested this approach on species such as the Asian gypsy moth, white pine blister rust and sudden oak death pathogen, which are listed among the most destructive invasive pests worldwide.

“Our forestry, agriculture and horticulture are vital industries contributing billions of dollars to Canada’s economy so it’s essential that we protect them from their enemies,” added Hamelin. “With early detection and steady surveillance, we can ensure that potential problems are nipped, so to speak, in the bud.”

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Thursday, 09 July 2020 12:42:00

From PestNet

Grahame Jackson posted a new submission ‘UNDIAGNOSED RUST, MAIZE – KENYA: (BARINGO)’

Submission

UNDIAGNOSED RUST, MAIZE – KENYA: (BARINGO)

ProMED
https://promedmail.org/

Source: The Standard, FarmKenya [edited]
https://www.farmers.co.ke/article/2001376657/fears-as-deadly-maize-rust-affects-3-000-acre-field
Farmers contracted to grow certified maize seeds in Baringo are staring at losses following [an] outbreak of maize rust disease. There are 8 farmer-managed schemes contracted to plant seed maize on 3000 acres [1214 hectares].
[One farmer] said the crop germinated evenly, but was hit by the fungal disease at the flowering stage and [the disease] was spreading fast. “Several varieties of maize were grown, but the disease affected one variety that we fear might cause us more losses,” [he] said. Leaves of the crop appeared brown and rusty.
Kenya Seeds Company that contracted [the] farmers are inspecting the farms. [They] attributed the disease to cold weather following heavy rains, saying it could be managed by spraying fungicides. Extension officers have been sent to the ground to find mitigation measures.

Communicated by:
ProMED-mail
<promed@promedmail.org>
[There are 3 rusts affecting maize: common rust caused by _Puccinia sorghi_; southern rust caused by _Puccinia polysora_; and tropical rust caused by _Phakopsora zeae_. (For more information, see previous ProMED-mail posts in the archives and links below.)
Rust spores are wind dispersed over long distances. They can also be spread by mechanical means (human or insect activities) and on contaminated materials (equipment, clothing, crop debris). The fungi need living tissue to survive between seasons. Volunteer crop and wild host plants may generate a “green bridge” providing inoculum to infect new crops. Disease management relies mainly on timely fungicide applications, choice of crop cultivars, and control of volunteer crop plants. Early discovery of infection is important so action can be taken to limit pathogen spread as well as build-up of inoculum.
Maps
Kenya:
https://www.nationsonline.org/maps/kenya_map.jpg and
http://healthmap.org/promed/p/48354
Kenya counties:
https://www.mapsofworld.com/kenya/kenya-political-map.html
Pictures
Symptoms of some maize diseases via:
http://www.ipmimages.org/browse/Areasubs.cfm?area=72
Links
Information on common and southern maize rusts via:
http://maizedoctor.cimmyt.org/pests-diseases/list and
https://www.pestnet.org/fact_sheets/maize_common_rust_225.htm
List of major diseases and pathogens of maize:
https://www.apsnet.org/edcenter/resources/commonnames/Pages/Corn.aspx
Fungal taxonomy and synonyms via:
http://www.indexfungorum.org/Names/Names.asp
– Mod.DHA]


An inter-country workshop and an experience-sharing session on a virtual platform

Community Business Facilitators (CBF) plant doctor Mr Gannesh Rokaya and Mrs Dipa Poudel of Surkhet giving farmers a technical consultation

Our experiences in Nepal during the global COVID-19 pandemic have been both positive and negative. On the positive side, this difficult time has made us realize the value of coming together and being connected as a community. But the pandemic has also put people’s lives and livelihoods at risk. In Nepal, COVID-19 is now spreading quickly. There is a strong need to protect the most vulnerable and to mitigate the pandemic’s impacts across the country’s food system.

Amidst the COVID-19 pandemic, iDE Nepal has been working in coordination with all the collaborative partners of the Plantwise programme, as well as with government agencies, to adapt and improve the ways in which integrated pest management (IPM) technology and related information is communicated and delivered to smallholder farmers.

Most recently, iDE Nepal teamed up with CABI Plantwise and government agencies to host a workshop on the validation of plant clinic data contained in the Plantwise Online Management System (POMS). The three-day workshop (29–31 May) was hosted on an online platform (Zoom) and was attended by agriculture technicians from iDE Nepal and agriculture experts from Jammu, India. The facilitation of the workshop was carried out by resource personnel (Senior Plant Protection Officers) from the national Plant Quarantine and Pesticide Management Centre (PQPMC) and the Agriculture Development Directorate, Pokhara. The guest speakers at the workshop were Dr Vinod Pandit (CABI), Dr Corey O’Hara (Country Director, iDE Nepal) and Mr Komal Pradhan (National Programme Director, iDE Nepal).

The major objective of the validation workshop was to train agriculture technicians at iDE Nepal to harmonize, validate and analyse the plant clinic data managed by iDE Nepal in POMS. The validation of clinic data is crucial in order to evaluate the recommendations and advice given by plant doctors to farmers through plant clinics, and ultimately to enhance the quality of recommendations for the control of insect pests and diseases through IPM. The validation of clinic data is equally important in order to record the quality of services provided by CBF plant doctors, which can be later used as a basis for providing follow-up training to CBF plant doctors at iDE Nepal.

In addition to the valuable validation session facilitated by resource personnel, the experience-sharing session on the validation of clinic data by experts from Jammu, India, was of major help in easing the practical difficulties faced in the validation of clinic data.

Overall, the workshop was a success considering the learning gained on the validation of clinic data. It was also a beneficial platform for strengthening coordination with government bodies, and for inter-country experience-sharing with the ultimate goal of providing quality services to small-holder farmers.

Read more about Plantwise in NepalIntegrated Pest management, Nepal, covid-19, digital development, plant clinics, plant doctors, smallholder agricultureAgriculture and International Development, Development communication and extension, Digital development

The white mold fungus Sclerotinia sclerotiorum detoxifies the mustard oil bomb in plants of the cabbage family

Date: June 19, 2020 Source: Max Planck Institute for Chemical Ecology Summary: Cabbage plants defend themselves against herbivores and pathogens by deploying a defensive mechanism called the mustard oil bomb. Researchers have now been able to show that this defense is also effective against the widespread fungus Sclerotinia sclerotiorum. However, the pathogen uses at least two different detoxification mechanisms that enable the fungus to successfully spread on plants defended in this way. Share: FULL STORY


Cabbage plants defend themselves against herbivores and pathogens by deploying a defensive mechanism called the mustard oil bomb: when the plant tissue is damaged, toxic isothiocyanates are formed and can effectively fend off attackers. Researchers at the Max Planck Institute for Chemical Ecology and the University of Pretoria have now been able to show in a new study that this defense is also effective to some extent against the widespread and detrimental fungus Sclerotinia sclerotiorum. However, the pathogen uses at least two different detoxification mechanisms that enable the fungus to successfully spread on plants defended in this way. The metabolic products thus formed are non-toxic to the fungus, allowing it to grow on these plants.

Sclerotinia sclerotiorum is a devastating fungal pathogen that can infect more than 400 different plant species. The main symptom of the disease called Sclerotinia wilt or white mold is wilting. Visible are also the white, cotton-like fungal spores that overgrow plant leaves and stalks. In agriculture, rapeseed cultivation is particularly at risk. The plant disease can affect other members of the cabbage family, and also potatoes, legumes and strawberries.

Scientists at the Max Planck Institute for Chemical Ecology in Jena have long been studying the glucosinolates and isothiocyanates that constitute the special defense mechanism of cabbage family plants, which include rapeseed, radishes and mustard. “We wanted to find out how successful plant pathogens overcome the plant defense and colonize these plants. We therefore asked ourselves whether widespread fungal pathogens have strategies to adapt to the chemical defenses of plants of the cabbage family,” Jingyuan Chen, the first author of the study, explains.

The researchers were able to show experimentally that the defense based on glucosinolates is actually effective against fungal attacks. However, they also discovered two different strategies of the white mold fungus to detoxify the defensive substances: The first is a general detoxification pathway that binds glutathione to the isothiocyanate toxins. This type of detoxification of organic poisons is quite common in insects and even mammals. The second and far more effective way to render the isothiocyanates harmless is to hydrolyse them, i.e. to cleave them enzymatically with a water molecule. The researchers wanted to identify the enzymes and corresponding genes underlying this detoxification mechanism. Genes that enable the successful detoxification of these substances had already been described in bacteria. They are called Sax genes after experiments with the model plant Arabidopsis thaliana: Survival in Arabidopsis eXtracts.

“We based our search on the known bacterial SaxA proteins to select candidate genes for further investigations. We then tested whether these genes are actually expressed in greater quantities in fungi exposed to the toxins, and whether the resulting protein can render the toxins harmless,” explains Daniel Vassão, one of the study leaders. Using high-resolution analytical methods, the scientists were able to identify and quantify the metabolites produced by the fungus during detoxification. They also used mutants of the fungus in which the SaxA-encoding gene had been knocked out for comparison. This revealed that the Sax protein of the white mold fungus is active against a range of isothiocyanates, allowing it to colonize different plants of the cabbage family.

Mutants lacking the gene for this detoxification pathway were dramatically reduced in their capacity to tolerate isothiocyanates. “However, it was surprising to see that these mutants up-regulated their general pathway of detoxification, although this did not compensate for the mutation,” says Jingyuan Chen. Glutathione conjugation cannot detoxify isothiocyanates nearly as effectively as hydrolysis can. Although it seems to be metabolically more expensive for the fungus, this general pathway is always present as it helps the fungus to detoxify a huge variety of poisons. “It is possible that this general pathway protects the fungus initially, while the machinery required for the more specialized pathway is assembled after an initial exposure to the toxin and can take over later in the infection,” says Daniel Vassão.

In further experiments, the researchers want to investigate whether other fungi that successfully infect plants of the cabbage family also detoxify isothiocyanates via the same pathway, and whether unrelated fungal species are also able to degrade these toxins. “Then we will know whether this widespread detoxification is due to repeated evolution in fungi colonizing mustards, or is a feature which has been conserved over time and is therefore found in many fungal lines,” Jonathan Gershenzon, director of the Department of Biochemistry where the research was conducted, concludes.


Story Source:

Materials provided by Max Planck Institute for Chemical Ecology. Note: Content may be edited for style and length.


Journal Reference:

  1. Jingyuan Chen, Chhana Ullah, Michael Reichelt, Franziska Beran, Zhi-Ling Yang, Jonathan Gershenzon, Almuth Hammerbacher, Daniel G. Vassão. The phytopathogenic fungus Sclerotinia sclerotiorum detoxifies plant glucosinolate hydrolysis products via an isothiocyanate hydrolase. Nature Communications, 2020; 11 (1) DOI: 10.1038/s41467-020-16921-2

Cite This Page:

Max Planck Institute for Chemical Ecology. “Fungal pathogen disables plant defense mechanism: The white mold fungus Sclerotinia sclerotiorum detoxifies the mustard oil bomb in plants of the cabbage family.” ScienceDaily. ScienceDaily, 19 June 2020. <www.sciencedaily.com/releases/2020/06/200619104310.htm>.


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