Feeds:
Posts
Comments

Archive for the ‘Uncategorized’ Category

After 17 Years Underground, the Brood X Cicadas are Coming!

George Washington University researchers are studying the impact of the cicadas on the ecosystem and environment
George Washington University

4-May-2021 12:05 PM EDT, by George Washington Universityfavorite_border

Newswise: After 17 Years Underground, the Brood X Cicadas are Coming!

Martha Weiss

Within 12 hours, the cicadas take on the black and orange look that you see here. Even though they are now adults, these cicadas are still pretty awkward and often fall or accidentally flip themselves over.

Newswise — WASHINGTON (May 4, 2021)—Billions of Brood X cicadas will begin emerging within the next week or so in the Eastern United States after spending 17 years underground. They will sing mating calls, lay eggs, and then die. Once the eggs hatch sometime in August, the immature nymphs will burrow deep into the ground and this seventeen-year life cycle will start all over again.

Researchers at the George Washington University are studying the Brood X cicadas, which are part of a large order of insects known as hemipterans. John Lill, chair of the Department of Biological Sciences at GW and Zoe Getman-Pickering, a postdoctoral scientist at GW, plan to look at the impact the cicadas will have on the local ecosystem. 

For example, the team will collect data on birds that normally eat caterpillars to see if they will alter their diet to feast on the bonanza of cicadas instead. Lill and Getman-Pickering predict that if the birds change their diet, more caterpillars will survive this year and typical patterns of leaf damage in local forests will be altered.

Such research will provide scientists with a better understanding of this natural phenomenon, but many mysteries about the cicadas remain unsolved, Lill said. For example, no one knows how these insects keep track of time, or how long the ecological impacts of the emergence persist. 

Lill, Getman-Pickering, and their collaborator, Martha Weiss, a professor of biology at Georgetown University, began collecting data on bird diets and leaf damage during the spring and summer of 2020. They’re now monitoring the soil temperature in anticipation of the big emergence event. Scientists know that the nymphs tunnel their way out of the ground when the soil temperature reaches 64 degrees Fahrenheit.

Some of the nymphs may come out a few days early but there will be a massive emergence over the course of a few days, sometime this week or next, Lill predicts.

What happens next? The nymphs molt for the last time, spread their wings and soon start to look like the familiar adult black and orange cicadas, he said.

About a week after the emergence begins, the males start to sing courtship songs — some are as loud as 100 decibels — louder than a leaf blower or lawn mower. The females make a clicking noise to signal their interest and mating ensues.

The GW scientists will continue their research over the summer as the next generation of these 17-year cicadas hatch and burrow into the ground.

“We hope that our research will tell us more about how the cicadas affect local communities and the ecosystem,” Lill said. “By sharing the story of the cicadas, we hope the general public will start to view this natural phenomenon as a source of delight.”

Lill and Getman-Pickering have also been producing educational materials to teach K-6 students about cicadas. These can be downloaded for free at FriendToCicadas.org.

-GW-REQUEST AN EXPERT

MEDIA CONTACT

REGISTER FOR REPORTER ACCESS TO CONTACT DETAILS

TYPE OF ARTICLE

Feature

SECTION

SCIENCE

CHANNELS

Environmental Science

KEYWORDS

CicadasCicadacicada invasionBUGSInsectsEntomologyEntomologistsEntomology ResearchGeorge Washington UniversityGWUGWBiologyBiology (Ecology/Environment)Biological SciencesPrintFacebookTwitterLinkedInEmailMore

Read Full Post »

Weed invaders are getting faster

15/04/2021ASPSNewsPlant HealthPlant Science

  • A new study from James Cook University shows invasive plants are adapting to new habitats and new climates at an increasing pace – and especially so in tropical environments.

Dr Daniel Montesinos is a Senior Research Fellow at the Australian Tropical Herbarium in Cairns and is studying weeds to better understand (among other things) how they might respond to climate change.

He said most invasive plants are characterised by their rapid pace when it comes to taking up nutrients, growing, and reproducing – and they’re even faster in the regions they invade.

“New experiments comparing populations from distant regions show a clear trend for already-fast invasive plants to rapidly adapt even faster traits in their non-native regions,” Dr Montesinos said.

This is further pronounced in the tropics and sub-tropics.

“Even though invasives’ growth rates are already among the highest for plants, when they invade new territory in the tropics and sub-tropics, they develop those weedy traits more rapidly than they do when they invade in temperate climates,” Dr Montesinos said.

“This might be explained by higher chemical processing at higher temperatures, which suggests that global warming will increase invasive impacts in these regions, as long as enough water is available.”

Dr Montesinos said invasive plants usually take hold in land that has been disturbed by human intervention (for example farms and roadsides) and then spread to other habitats.

“It’s important to recognise disturbed habitats as a gateway for plant invasions,” Dr Montesinos said. “If we can limit disturbance of natural environments, we can reduce biological invasions, particularly in tropical areas that are threatened by increasing human encroachment.”

Dr Montesinos said that range expansions by native species trying to ‘escape’ from changes in climate could be a further complication. This involves climate change enabling some native plants to grow where they previously could not.

“This can be seen as a double-edged sword – some native species will survive climate change, but they might achieve that by disrupting the habitats of others.

“The study of invasion ecology is complex, but invasive species can be models in which to study, and make predictions about, the responses of native plants to climate change, giving us clues on improved management techniques for both natives and invasives,” Dr Montesinos said.

‘Fast invasives fastly become faster: Invasive plants align largely with the fast side of the plant economics spectrum’ is published in the latest edition of the British Ecological Society’s Journal of Ecology.

Read the paperJournal of Ecology

Article source:  James Cook University

ImageNicotiana glauca, Desert Botanical Garden, Phoenix, Arizona. CreditMiwasatoshi/Wikimedia

Read Full Post »

Diverse pollinators improve canola production

Study shows the proximity of canola fields to semi-natural areas can increase yield
American Society of Agronomy (ASA), Crop Science Society of America (CSSA), Soil Science Society of America (SSSA)

14-Apr-2021 9:00 AM EDT, by American Society of Agronomy (ASA), Crop Science Society of America (CSSA), Soil Science Society of America (SSSA)favorite_border

Newswise: Diverse pollinators improve canola production

Mariana Paola Mazzei

Nets are used to collect pollinating insects on canola flowers. Only the insects that are feeding on the flower are captured for later identification in the laboratory. PreviousNext

Newswise — April 14, 2021 – Farmers pay attention to many aspects of their crops. They carefully track how much water they are giving them and the amount of fertilizer they are using. But what about how many bees and butterflies are visiting? 

Mariana Paola Mazzei, a researcher specializing in crop pollination, and her collaborators think it’s time to start caring more about pollinators. They stress that it’s important to have what are called semi-natural areas around crop fields. This helps more pollinators visit the crops. 

The team’s research was recently shared in Crop Science, a journal of the Crop Science Society of America.

Their recent research tested if canola plants in Argentina have a better yield if they are close to semi-natural areas. These areas have more pollinators. They looked at how pollinators affected different aspects of canola production. This included the total number of fruits, seeds per pod, and seed mass. 

“Pollinating insects visit flowers to feed on nectar, pollen, or both,” Mariana P. Mazzei explains. “This flower-pollinator interaction allows pollen flow between flowers, carried on insects.”  

Pollinators can help increase yield by putting a higher number of pollen grains on a flower. This means there will be more seeds produced per pod. Also, if more flowers per plant are fertilized, there will be more total seeds in a field. 

Their results showed that the closeness of the crop to semi-natural habits can indeed increase the yield of canola. The closer the canola was to the pollinators, the more yield increased. 

The team also looked at what pollinators were present in the canola fields. The types of pollinators, quantity of pollinators, and diversity of pollinators visiting crop fields are all important factors. 

Honey bees were the most common and important pollinator. Researchers also found native species, such as types of hoverflies, flies, butterflies, wasps, and carpenter bees. Some of the species were found pollinating canola for the first time. 

“The number of pollinating species is important because a higher diversity means more chance of fertilization and seed production in this crop,” Mariana P.  Mazzei says. “Seeing new species of pollinating insects in this crop allows us to make better recommendations to help semi-natural habitats. It also helps design future ideas to help the pollinators.”

The research team offers many strategies for increasing the number of pollinators. The most important is to diversify the landscape to make it more welcoming to pollinators. This can start with diversifying the crops themselves.

“A diversity of crops that bloom at different times will attract more pollinators throughout the year.” Mariana P. Mazzei explains. “Having a lot of the landscape be the same crop reduces the stability of pollinating species and how many there are.”

“These plots of diverse crops should be merged with semi-natural habitats,” she adds. Having semi-natural areas throughout the landscape helps pollinators move between them.

“These sites provide shelter, nesting sites, and different food items for the pollinators along the season,” says Mariana P.  Mazzei. “The main policy recommendation to help crop pollination is having a minimum level of semi-natural habitats around crop plots.”

A last strategy is to create a crop management plan that is good for pollinators. This means, for example, reducing chemical use or using them at night or evening. This is when pollinators are less likely to be affected by them. 

“People usually think of insects as bad for crop plants,” Mariana P. Mazzei says. “They may not understand why pollinating insects are good. We showed that even in landscapes of central Argentina with a lot of agriculture and a low natural biodiversity, pollination is an important input for canola production.”

Mariana Paola Mazzei is a researcher at the National University of Rosario. This research was funded by Argentina’s National Scientific and Technical Research Council (CONICET), the National University of Cordoba, the Fund for Scientific and Technological Research (FONCyT), and Syngenta. 

###

LINK:

Crop Science (Journal) https://doi.org/10.1002/csc2.20450

TAGS:Agriculture, Production Agriculture, Canola, Crop Science, Conservation, Environment, Pollinators, Habitat, Natural Resources

PHOTOS: 

Paola Mazzei collection net 20150818_151033: Nets are used to collect pollinating insects on canola flowers. Only the insects that are feeding on the flower are captured for later identification in the laboratory. Credit: Mariana Paola Mazzei 

SEE ORIGINAL STUDY REQUEST AN EXPERT

Read Full Post »

New study may in the long term lead to new varieties that require less fertilizer

Date:April 8, 2021

Source: University of Bonn

Summary:A current study by scientists sheds light on an unusual interdependence: Maize can attract special soil bacteria that, in turn, help the plants to grow better. In the long term, the results could be used to breed new varieties that use less fertilizer and therefore have less impact on the environment.Share:FULL STORY


Every third-grader knows that plants absorb nutrients from the soil through their roots. The fact that they also release substances into the soil is probably less well known. And this seems to make the lives of plants a lot easier.

That is at least the conclusion of the current study. The participating researchers studied several maize varieties that differ significantly in their yield. In their search for the cause, they came across an enzyme, flavone synthase 2. “The high-yield inbred line 787 we studied contains large amounts of this enzyme in its roots,” explains Dr. Peng Yu of the Institute of Crop Science and Resource Conservation (INRES) at the University of Bonn. “It uses this enzyme to make certain molecules from the flavonoid group and releases them into the soil.”

Flavonoids give flowers and fruits their color. In the soil, however, they perform a different function: They ensure that very specific bacteria accumulate around the roots. And these microbes, in turn, cause the formation of more lateral branches on these roots, called lateral roots. “This allows the maize plant to absorb more nitrogen from the environment,” explains Prof. Dr. Frank Hochholdinger of the Institute of Crop Science and Resource Conservation (INRES). “This means the plant grows faster, especially when nitrogen supplies are scarce.”

Sterilized soil did not cause a growth spurt

The researchers were able to demonstrate in experiments how well this works. They did this using a maize variety with the abbreviation LH93, which normally produces rather puny plants. However, that changed when they planted this variety in soil where the high-performance line 787 had previously grown: LH93 then grew significantly better. The effect disappeared when the botanists sterilized the soil before repotting. This shows that the enriched bacteria are indeed responsible for the turbo growth, because they were killed during sterilization.

The researchers were able to demonstrate in another experiment that the microorganisms really do promote the growth of lateral roots. Here, they used a maize variety that cannot form lateral roots due to a mutation. However, when they supplemented the soil with the bacterium, the roots of the mutant started to branch out. It is not yet clear how this effect comes about. Additionally, with microbial support the maize coped far better with nitrogen deficiency.

Results may contribute to more sustainable agriculture

Nitrogen is extremely important for plant growth — so much so, that farmers artificially increase its amount in the soil by applying fertilizer. However, some of the fertilizer is washed off the fields into streams with the rain or enters the groundwater. It can also enter the atmosphere in the form of nitrogen oxides or as ammonium gas, where it contributes to the greenhouse effect. The production of nitrogenous fertilizers furthermore requires a great deal of energy. “If we breed crops that can improve their nitrogen usage with the help of bacteria, we might be able to significantly reduce environmental pollution,” Yu hopes.

The study shows that plants help to shape the conditions of the soil in which they grow, in ways that ultimately benefit them. However, this aspect has been neglected in breeding until now. Dr. Peng Yu adds that, in general, many interactions of the root system with soil organisms are not yet well enough understood. He wants to help change that: He has just taken over the leadership of an Emmy Noether junior research group at the University of Bonn, which is dedicated to precisely this topic. With its Emmy Noether Program, the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) offers young researchers an opportunity to qualify for a university professorship within six years.


Story Source:

Materials provided by University of BonnNote: Content may be edited for style and length.


Journal Reference:

  1. Peng Yu, Xiaoming He, Marcel Baer, Stien Beirinckx, Tian Tian, Yudelsy A. T. Moya, Xuechen Zhang, Marion Deichmann, Felix P. Frey, Verena Bresgen, Chunjian Li, Bahar S. Razavi, Gabriel Schaaf, Nicolaus von Wirén, Zhen Su, Marcel Bucher, Kenichi Tsuda, Sofie Goormachtig, Xinping Chen, Frank Hochholdinger. Plant flavones enrich rhizosphere Oxalobacteraceae to improve maize performance under nitrogen deprivationNature Plants, 2021; DOI: 10.1038/s41477-021-00897-y

Cite This Page:

University of Bonn. “Bacteria help plants grow better: New study may in the long term lead to new varieties that require less fertilizer.” ScienceDaily. ScienceDaily, 8 April 2021. <www.sciencedaily.com/releases/2021/04/210408152258.htm>.

Read Full Post »

The following link will take you to a recording of the parthenium webinar presented by the FTF Innovation Lab at VA Tech presented March 30, 2021.

https://drive.google.com/drive/folders/1BOSAFBic_HZo1k7qRa2MkqbDoXUQxDpm?usp=sharing

Housekeeping information/instructions                 Sara Hendery                     5 minutes           

Introduction to the webinar:                                   R. Muniappan                 10 minutes

Biological control of parthenium in Australia:       K. Dhileepan                      15 minutes

Biological control of parthenium in South Africa: Lorraine Strathie               10 minutes

Biological control of parthenium in East Africa:   Wondi Mersie                    10 minutes

Biological control of Parthenium in India:            N. Bakthavatsalam              5 minutes

Biological control of parthenium in Nepal:          P.K. Jha                               5 minutes

Biological control of parthenium in Pakistan       Kazam Ali                            5 minutes

Discussion/questions and answers                                                                  50 minutes

Closing remarks                                                  Van Crowder                   5 minutes

For further information contact:

Sara Hendery

Communications Coordinator

IPM Innovation Lab

saraeh91@vt.edu

Read Full Post »

The humble beetle that could rescue a town Share using EmailShare on TwitterShare on FacebookShare on Linkedin(Image credit: Alamy)

Salvinia has an enormously rapid growth rate and can engulf a lake, smothering the ecosystem and killing fish and mammals (Credit: Alamy)

By Nalova Akua29th March 2021An invasive water weed has decimated the wildlife and economy of one of Cameroon’s most significant lakes. But a tiny, ravenous weevil could reverse the region’s fortunes.A

A flock of water birds scavenges for insects on the dense, leafy weed that covers much of Lake Ossa, one of Cameroon’s largest lakes. The water weed is so closely packed that it looks like wide, flat green pasture, and the sure-footed birds pick their way freely across it as if they were walking on land.

Five years ago, Lake Ossa was teeming with freshwater turtles, crocodiles and more than 18 families of fish. It was also a bastion of the African manatee, a species listed as vulnerable on the International Union for Conservation of Nature’s Red List. But today, the lake is eerily quiet and almost empty.

The thick layer of vegetation is Salvinia molesta, a species known locally as kariba weed or simply Salvinia, and it is the cause of this dearth of life in the lake. The invasion has been declared a “conservation emergency” by the IUCN.

Salvinia, a free-floating, green-brown freshwater fern, has already invaded more than 40% of the lake’s 4,000-hectare (15.4-sq-mile) surface, according to the African Marine Mammal Conservation Organisation (AMMCO), a Cameroonian non-governmental environmental organisation.

Story continues below

Not far from the lake’s shore, an army of weevils is now being mass-reared as a defence against Salvinia

Decimating the lake’s wildlife, and compromising the main source of income for the local population, the Salvinia takeover has been rapid and seemingly unstoppable. Lake Ossa is only one in a long line of freshwater bodies to be engulfed by Salvinia. As this invasive weed has spread around the world, from Brazil and Argentina to Australia, the efforts to control it have struggled to keep pace with the plant’s prolific growth.

But there is hope for Lake Ossa, and it comes in the shape of a small, innocuous-looking but remarkably powerful water-dwelling beetle. Not far from the lake’s shore, an army of weevils is now being mass-reared as a defence against Salvinia.Lake Ossa is one of the largest lakes in Cameroon, and was home to a wealth of biodiversity before Salvinia arrived (Credit: AMMCO)

Lake Ossa is one of the largest lakes in Cameroon, and was home to a wealth of biodiversity before Salvinia arrived (Credit: AMMCO)

Lake Ossa is today littered with weed-laden fishing nets – abandoned by the local fisherfolk out of frustration. Wooden fishing boats have been hauled onto the lake’s shorelines – some have been there so long they are starting to rot. Those local fishermen who are still actively fishing in the lake, and the women who sell the fish caught, say they have lost about 80% of their income.

Lake Ossa used to be home to scores of African manatees, one of the most sparsely studied manatee species. Their population in the lake now appears to be declining

In the sweltering late morning heat, I meet Dina Marie-Louise, a fish retailer and resident of the lakeside town of Dizangue, as she disembarks from a wooden fishing boat. In the local business for 22 years, Dina has been visiting fishermen in the lake to buy their catch. Today, she frowns at the few fish in her basket. “Salvinia is killing us,” she says. “Seven of my 12 children have dropped out of school because of financial difficulties caused by Salvinia.”

Roland Ngolle, who has been fishing in the lake for 12 years, paints a similar picture. “We are running out of space to fish in this lake. If nothing is done, Salvinia will engulf all of Lake Ossa,” Ngolle says. “More than 100 fishermen used to visit this lake in a single morning. Today less than five come to fish. Everybody is discouraged.”

As well as fish, Lake Ossa used to be home to scores of African manatees, one of the most sparsely studied manatee species. Their population in the lake now appears to be declining. Many of the manatees are thought to be leaving the lake for its surrounding rivers, where they have better access to food, says Aristide Takoukam Kamla, founder of AMMCO.The larvae of the Salvinia weevil are highly destructive and can bring a freshwater habtitat back into ecological balance (Credit: Alamy)

The larvae of the Salvinia weevil are highly destructive and can bring a freshwater habtitat back into ecological balance (Credit: Alamy)

Salvinia is native to southern Brazil and northern Argentina, but it can spread between water bodies by wind, water currents, floods, animals and people. “[The] human factor is partly to blame for the presence of the invasive plant in the Cameroon lake,” says Kamla.

As well as physically moving the plant from one place to another, for example when it hitches a ride on boats, human activity is also thought to be responsible for allowing Salvinia to thrive in the lake.

“We noticed a heavy concentration of nutrients such as nitrogen and phosphorous in Lake Ossa in 2016 – doubling from the historical value of 1985,” says Kamla. “This was a signal that something was happening in the lake called eutrophication, which is simply the enrichment of the lake in terms of nutrients.”

That made conditions perfect for Salvinia to proliferate. “The carpet formed by the plant at the surface prevents light from penetrating the water column and therefore reduces photosynthesis of phytoplankton on which most fish species feed,” says Kamla. “This results in a drastic depletion of fish production.”

With a fast-growing plant that can double in size every 10 days, the plant’s growth is almost unstoppable. “The absence of [Salvinia’s] natural enemies in a foreign environment facilitates its fast growth rate,” says Lum Fontem, an independent plant scientist based in Cameroon.Numbers of the African manatee, pictured here in captivity, are in decline (Credit: Getty Images)

Numbers of the African manatee, pictured here in captivity, are in decline (Credit: Getty Images)

At every strategic corner of the bumpy earth roads around Dizangue, billboards carry messages alerting villagers and visitors to the Salvinia problem. Messages such as “Youths, Let’s Save Lake Ossa”; “Let’s Save Our Lake From Salvinia Invasion” appear on countless signs around the town. This may be Cameroon’s first experience of a Salvinia invasion, but there has already been an intensive response to it.

There are three main ways that the weed can be removed. The first, and most physically demanding, is removing it manually. “This includes hand-pulling, mostly for low infestation, and the use of specialised equipment, for high infestation,” says Fontem. “This method is labour-intensive, tedious and time-consuming.”

Since 2019, AMMCO has been mobilising locals to remove the plant manually to reduce the scope of spread. But it has not been without challenges. “This method is very demanding given that the invasive plant multiplies very quickly,” says Kamla. “We removed over 200 tonnes of Salvinia from the lake in 2019 and 2020. Yet, no impact was felt.”

This is because manual removal of Salvinia alone is not enough to control the weed, Lum says. Any plant left in the water will rapidly grow to replenish what has been stripped away.

The second option is chemical control, which involves the application of herbicides to kill the weed. But this comes with its own ecological drawbacks, as the herbicides pose a risk to other plants and could harm the lake’s other organisms. So far, the chemical approach has not been tried at Lake Ossa, and scientists including Fontem caution against trying it.

But there is one final option that could relieve Lake Ossa of Salvinia and restore its ecosystem: a small, brown-black water beetle native to Brazil known as the Salvinia weevil, which feeds almost exclusively on the weed. Measuring just 2-3.5mm long in its adult form, this tiny insect is equipped with a long, sturdy snout. But it is the weevil larvae that are devastating to the Salvinia by burrowing into the plant’s rootstalks and causing fatal damage.Removing Salivinia by hand is very labour intensive, but so far it is the only method that has been attempted at Lake Ossa (Credit: AMMCO)

Removing Salivinia by hand is very labour intensive, but so far it is the only method that has been attempted at Lake Ossa (Credit: AMMCO)

The Salvinia weevil was discovered by Wendy Forno, a scientist at Australia’s government research agency CSIRO, while carrying out surveys in South America between 1978 and 1982. The first releases of the weevil as a biological agent to destroy Salvinia were at Lake Moondarra, Mount Isa, Australia in 1980, with remarkable success.   

“Lake Moondarra is mostly clear of Salvinia today. Fifty thousand tonnes of Salvinia on the lake was killed by weevils over a 400-hectare (1.5-sq-mile) infestation,” says Matthew Purcell, director of the Australian Biological Control Laboratory, a facility run by the United States Department of Agriculture and CSIRO.

“The weevil – both adults and larvae – only feeds on this fern and not on other aquatic plants,” says Purcell. “As the plants increase seasonally, so do the weevils. The weevils [and] Salvinia constantly increase and decrease through the seasons in balance.” The weevils never fully eradicate the weed, but help to “return the system to a balance”, says Purcell.  

The weevil was also deployed in the Senegal River in the early 2000s, where it had similar success, says Arnold Pieterse, formerly a senior staff member of the Netherlands’ Royal Tropical Institute, now retired. He, too, underlines that the weevils’ strong preference for Salvinia as a food crop makes it an appealing choice for Salvinia control. “It has irrefutably been proven that the insects do not form any danger to the environment or crops,” says Pieterse.

South Africa, too, has successfully brought Salvinia molesta under control thanks to the release of the weevil into its fresh water systems since 1985. “South Africa had a number of systems infested with the weed throughout the country, mainly smaller impoundments and rivers,” says Julie Coetzee, deputy director and manager of the Aquatic Weed Biocontrol Programme at Rhodes University, South Africa. These waters took between one to three years to clear, depending on the nutrients in the water, and the climate. “We still do have some infestations appearing,” Coetzee says, but “once weevils have been released, we typically get clearing with a season”.The Salvinia weevil was first tried as a method to control the weed in Australia, where it has also invaded rivers and lakes (Credit: Getty Images)

The Salvinia weevil was first tried as a method to control the weed in Australia, where it has also invaded rivers and lakes (Credit: Getty Images)

Though the Salvinia has no defence against the weevil, the weevils themselves have weaknesses. “No drawbacks were experienced initially but nowadays, we have noticed that there are sites where infestations have persisted, particularly in shaded sites,” says Coetzee. “We have also discovered a parasitic alga infecting [the weevil] population.” This alga, called Helicosporidium, reduces the weevil’s ability to reproduce.

Nevertheless, Coetzee is optimistic that weevils could clear Cameroon’s Lake Ossa of Salvinia. “Implementing a biological control programme in Cameroon is the most ecologically friendly, economically sustainable option for control of Salvinia,” she says. “Given the size of the infestation on the lake, it is going to take a while for the control agent populations to build up to sizes that will damage the plants, and cause them to sink. This is not a fast process. Patience is key.”

Purcell, too, is hopeful that the weevils could rejuvenate Lake Ossa. “The weevils should work in Cameroon. Most control is achieved within three years,” he says. “The control lasts indefinitely, much better than spraying which must be reapplied every year and every season, with negative consequences to the aquatic environment.”

It may not be much longer before Lake Ossa becomes the next Salvinia-ridden water body to welcome weevils. A task force involving several of Cameroon’s government ministries has been set up to oversee the eradication of Salvinia in the lake through the release of the weevils.

The local people of Lake Ossa, though, are frustrated at the pace of action. “Fishing is our only source of income. We are running out of patience,” says Jean Pierre Nga, a fisherman. Dora Sih, a fish seller in the business for 25 years, agrees: “Things are not moving.”

But in AMMCO and their partners’ facilities in Dizangue, the stock of weevils is steadily growing. “They will be released into the lake as soon as we receive the authorisation permit from the government,” Kamla says. “And we hope that after two or three years, we will overcome this invasive plant.”

The emissions from travel it took to report this story were 41kg CO2, travelling by bus and motorbike. The digital emissions from this story are an estimated 1.2g to 3.6g CO2 per page view. Find out more about how we calculated this figure here.

Join one million Future fans by liking us on Facebook, or follow us on Twitter or Instagram.

If you liked this story, sign up for the weekly bbc.com features newsletter, called “The Essential List”. A handpicked selection of stories from BBC FutureCultureWorklife, and Travel, delivered to your inbox every Friday.Share using EmailShare on TwitterShare on FacebookShare on Linkedin

Read Full Post »

Parthenium hysterophorus is a destructive weed native to Central and South America that has accidentally been introduced to many regions of the world including Australia, Asia, Africa, and the Pacific Islands. The weed dramatically reduces crop yields, impacts biodiversity, causes human health issues such as respiratory difficulty and rashes, and taints valuable livestock milk. Beginning in 2005, Virginia Tech’s Feed the Future Innovation Lab for Integrated Pest Management and Virginia State University initiated a classical biocontrol program to manage the weed in East Africa. Biocontrol programs have also been set up in Australia, South Africa, Pakistan, and India, with fortuitous introductions of natural enemies to Nepal. Zygogramma bicolorata – a leaf-feeding beetle – and Listronotus setosipennis – a stem-boring weevil – are the primarily natural enemies implemented in the biocontrol program, but a number of supplementary natural enemies have been introduced to Australia. The use of biocontrol to mitigate the spread of parthenium has demonstrated major success reducing the vegetative and reproductive aspects of the weed and restor-ing valuable land. This webinar will cover biocontrol of parthenium weed in both Asia and Africa, as well as how to develop a biocontrol program from start to finish, how to rear and release natural enemies, evaluation of suitable biocontrol sites, among other topics.

Read Full Post »

Job Description

Position: Assistant Professor located at the Texas A&M AgriLife Research Center at Beaumont.

Appointment: 100% research. Salary will be highly competitive and commensurate with experience.

Qualifications: A Ph.D. in Entomology or a closely related biological science is required. Preference will be given to candidates who have a strong research background in the genetic inheritance of host plant resistance traits, expertise with quantitative analysis of entomological and host plant interactions data, and a working knowledge of all aspects of field experiments needed to address the efficacy of host plant resistance traits and chemical controls. A proven track record of research productivity demonstrated through nationally recognized publications and external competitive research funding, and a demonstrated ability to clearly communicate research results to growers and consultants, are essential. Candidates who are crossed-trained in complementary areas of crop production and management are desired.

For full details see: Assistant Professor (myworkdayjobs.com) or contact:

Dr. M.O. (Mo) Way

Professor of Entomology

Texas AgriLife Research and Extension Center

1509 Aggie Drive

Beaumont, TX 77713

409.239.4265 (cell)

moway@aesrg.tamu.edu

Read Full Post »

NEWS AND VIEWS  05 MARCH 2021

Road map for domesticating multi-genome rice using gene editing

Having more than two sets of chromosomes can help plants to adapt and evolve, but generating new crops with this type of genome is challenging. A road map for doing just that has now been developed using wild rice.

Diane R. Wang

We all sometimes wish we could do more than one thing at once — run errands, catch up on work deadlines and perhaps grab that long-overdue coffee with a friend. A genetic state known as polyploidy helps some plant genomes to do just this. Most plants, like humans, are diploid, with two sets of every chromosome. But polyploid plants have four, six or even eight sets of chromosomes. These additions allow different copies of a gene to take on different roles, and provide a buffer against potentially harmful mutations. Accordingly, polyploidy has served as a common mode of evolution in flowering plants1Writing in Cell, Yu et al.2 outline a viable approach to producing a domesticated form of polyploid rice using gene editing. Their advance could allow us to reap the benefits of polyploidy in one of the world’s most important crop species.Read the paper: A route to de novo domestication of wild allotetraploid rice

All crop species evolved from wild ancestors, as humans saved and propagated plants that had favourable attributes — loss of seed-dispersal mechanisms, for instance, and larger seeds and fruits3 — over hundreds or thousands of years. The world’s main rice crop, the Asian species Oryza sativa, was domesticated about 9,000 years ago from its wild progenitor, Oryza rufipogon, through processes thought to have occurred across multiple regions in Asia4,5. Both species are diploid, carrying two sets of 12 chromosomes.

For rice scientists, the idea of developing polyploid cultivated rice is tantalizing as a potential means for future crop improvement, especially in the face of climate variability6. The plant’s extra gene copies might enable rapid adaptation in response to major changes in the environment without the loss of favourable features7. But generating a polyploid rice from a cultivated diploid plant is hugely technically challenging. With that in mind, Yu et al. took an entirely different approach. The authors started with a distant, wild polyploid cousin of O. sativa and O. rufipogon, and domesticated it using biotechnological approaches (Fig. 1).

Figure 1
Figure 1 | A fast track to cultivated polyploid rice. Yu et al.2 have developed a strategy for rapid domestication of wild polyploid rice (which has more than two sets of chromosomes, unlike the rice commonly grown as a food crop). The first step is to select a wild strain that has favourable characteristics for gene editing and crop production. This is followed by genomic analysis and method optimization. Iterative cycles of genome editing, conventional crossing and testing are then needed before the new crop is rolled out to farmers and evaluated. Red highlights indicate sections of the road map completed by the authors for the wild rice Oryza alta.

The authors first spent time identifying an appropriate starting strain. The ideal candidate needed to be amenable to callus induction and regeneration — a process in which plant tissues are cultured to produce a mass of partially undifferentiated cells called a callus, from which new plants are generated. These properties are essential for gene-editing techniques. The selected individual also needed to have high biomass and tolerance to various abiotic and biotic stresses — heat and insect resistance, for example. After screening 28 polyploid wild rice lines, a strain of Oryza alta was selected, and named polyploid rice 1 (PPR1).

Oryza alta has four sets of chromosomes (it is tetraploid), and is found in Central and South America8. The species arose as a result of hybridization between two ancestors that had diploid genomes, designated C and D. The PPR1 strain selected by Yu et al. looks quite different from cultivated O. sativa. For instance, it is very tall — more than 2.7 metres, compared with 1 metre or less for typical O. sativa. It produces abundant biomass, and has broad leaves and sparse, small seeds adorned with awns (spiky protrusions thought to aid seed dissemination). As such, domesticating this wild relative was no small feat.

Yu and colleagues established methods for gene editing in PPR1, and assembled a high-quality genome for the strain. This acted as a map that helped identify genes to target for domestication. The authors compared PPR1 with an O. sativa genome dubbed Nipponbare. They discovered about 10,000 genes in each of the C and D genomes that did not have equivalents (homologues) in Nipponbare. By contrast, about 39,500 genes in Nipponbare (70.41% of the genome) did have homologues in PPR1.Multiple genomes give switchgrass an advantage

The latter was a promising result, because it meant that the genes responsible for domestication in O. sativa probably had related versions in PPR1. The researchers edited a suite of such genes in PPR1 that were known to have been involved in the domestication of O. sativa. This led to a range of improvements in PPR1: loss of shattering (a seed-dispersal mechanism), so that seeds did not fall off the plant before harvest; reduced awn length to ease post-harvest processing; increased grain length for larger kernels and greater yield; decreased height and thickened stem diameter to support the heavier grains; and modified (both longer and shorter) flowering times, needed for local adaptation to different latitudes.

Together, Yu and colleagues’ efforts led to the production of PPR1 lines with domesticated features in a just few generations, fast-tracking a process that typically occurs over hundreds to thousands of years. The work opens the door to developing plants that not only can better withstand environmental stresses (a crucial characteristic for global food security in the face of changing climates), but also could carry other characteristics — enhanced nutrition and taste, for example — that might help rice to meet evolving consumer preferences in the future. In addition, the strategy the authors have devised could theoretically provide a road map for applying biotechnology to drive the domestication of wild relatives of other present-day crops.Keen insights from quinoa

The techniques established by Yu et al. await testing in other wild, tetraploid rice strains. Successful extension to a broader gene pool will be necessary if researchers and breeders are to generate a diverse repository of domesticated polyploids, which could then be used to generate further improved strains through conventional crosses or genome editing — strains adapted to particular production systems, for instance, or those with high market acceptability. And although wild polyploids hold great promise as yet-untapped sources of genes that confer tolerance to abiotic stresses such as drought, these traits are likely to be complex, as noted by the authors, being influenced by many genes, each of which has only a small effect. A deeper understanding of the genetics of these plants is needed for the full potential of wild rices to be appreciated.

There is a long journey ahead for the breeding of cultivated polyploid rice. But the first seeds have now been sown. As demand for nimble and resilient food systems rises, rapid domestication and improvement of wild plant species, including polyploids, may well become a valuable instrument in agriculture’s toolbox.doi: https://doi.org/10.1038/d41586-021-00589-9

Read Full Post »

Researchers find peptide that treats, prevents killer citrus disease

09/03/2021NewsPlant HealthPlant Science

  • Treatment causes deadly bacterium to leak and die

New research affirms a unique peptide found in an Australian plant can destroy the No. 1 killer of citrus trees worldwide and help prevent infection.

Huanglongbing, HLB, or citrus greening has multiple names, but one ultimate result: bitter and worthless citrus fruits. It has wiped out citrus orchards across the globe, causing billions in annual production losses.

All commercially important citrus varieties are susceptible to it, and there is no effective tool to treat HLB-positive trees, or to prevent new infections. 

However, new UC Riverside research shows that a naturally occurring peptide found in HLB-tolerant citrus relatives, such as Australian finger lime, can not only kill the bacteria that causes the disease, it can also activate the plant’s own immune system to inhibit new HLB infection. Few treatments can do both.

Research demonstrating the effectiveness of the peptide in greenhouse experiments has just been published in the Proceedings of the National Academy of Sciences.

The disease is caused by a bacterium called CLas that is transmitted to trees by a flying insect. One of the most effective ways to treat it may be through the use of this antimicrobial peptide found in Australian finger lime, a fruit that is a close relative of citrus plants.

“The peptide’s corkscrew-like helix structure can quickly puncture the bacterium, causing it to leak fluid and die within half an hour, much faster than antibiotics,” explained Hailing Jin, the UCR geneticist who led the research. 

When the research team injected the peptide into plants already sick with HLB, the plants survived and grew healthy new shoots. Infected plants that went untreated became sicker and some eventually died. 

“The treated trees had very low bacteria counts, and one had no detectable bacteria anymore,” Jin said. “This shows the peptide can rescue infected plants, which is important as so many trees are already positive.”

The team also tested applying the peptide by spraying it. For this experiment, researchers took healthy sweet orange trees and infected them with HLB-positive citrus psyllids — the insect that transmits CLas. 

After spraying at regular intervals, only three of 10 treated trees tested positive for the disease, and none of them died. By comparison, nine of 10 untreated trees became positive, and four of them died. 

In addition to its efficacy against the bacterium, the stable anti-microbial peptide, or SAMP, offers a number of benefits over current control methods. For one, as the name implies, it remains stable and active even when used in 130-degree heat, unlike most antibiotic sprays that are heat sensitive — an important attribute for citrus orchards in hot climates like Florida and parts of California.

In addition, the peptide is much safer for the environment than other synthetic treatments. “Because it’s in the finger lime fruit, people have eaten this peptide for hundreds of years,” Jin said. 

Researchers also identified that one half of the peptide’s helix structure is responsible for most of its antimicrobial activity. Since it is only necessary to synthesize half the peptide, this is likely to reduce the cost of large-scale manufacturing. 

The SAMP technology has already been licensed by Invaio Sciences, whose proprietary injection technology will further enhance the treatment.

Following the successful greenhouse experiments, the researchers have started field tests of the peptides in Florida. They are also studying whether the peptide can inhibit diseases caused by the same family of bacteria that affect other crops, such as potato and tomato.

“The potential for this discovery to solve such devastating problems with our food supply is extremely exciting,” Jin said.

Read the paperProceedings of the National Academy of Sciences

Article sourceUniversity of California – Riverside

Author: Jules Bernstein

Read Full Post »

Older Posts »