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Dominant, non-native plants reduce wetland biodiversity and abundance more than native plants do, researchers report in the journal Ecology Letters. Even native plants that dominate wetland landscapes play better with others, the team found.

The researchers analyzed 20 years of data collected by expert botanists from hundreds of randomly selected sites in Illinois. This allowed them to track changes in the variety and abundance of different plants in the same locations over time.

The dominant non-natives are not just choking out many other plants, the researchers report. They also have a broad ecological footprint, taking over wetlands on a regional level, rather than just in individual sites. This negatively affects populations of birds and insects that rely on the native wetlands.

“The more dominant they are, the less room is available for other species,” said Illinois Natural History plant ecologist and botanist Greg Spyreas, who conducted the research with INHS plant ecologist David Zaya and colleagues from the U.S. Geological Survey. “These non-natives become more dominant over time and their impact on the rest of the community is fundamentally different,” Spyreas said. “They outcompete better. And that’s across hundreds of sites.”

For example, a European cultivar of reed canary grass has taken hold in many parts of North America. It grows extremely fast, reduces the light available to other plants, produces enormous numbers of seeds and sends out underground stems to quickly colonize a site, Spyreas said.

“It creates this very thick thatch of dead material on the ground that other plants can’t penetrate – but it can,” he said. “It tolerates drought and flooding very well, whereas a lot of native plants cannot.”

Another offender, a non-native common reed, Phragmites, “is notable in its aggressiveness,” Zaya said. It can quickly crowd out other wetland species, including native Phragmites.

Not all non-native plants reduce the ecological richness of wetlands, Zaya said.

“There are non-natives that sit in the background and don’t affect the wetland community,” he said. “Also, many native plants will dominate wetland communities.”

Some researchers have hypothesized that it doesn’t matter if a dominant plant is native or non-native: Both can drive down the diversity and abundance of other species, Zaya said.

But the new study shows that dominant, non-native species are much more likely to radically diminish the biological diversity of a locale than their native counterparts will.

“When I see native- versus non-native-dominated wetlands, it looks like two totally different worlds,” Zaya said. “Each native wetland has its own personality, with a different little flower or forb or rare grass or sedge. No two are the same. But the non-native wetlands tend to look alike. They’re the same here as they are in Ohio.”

The data also offer insights into how to best maintain wetland diversity, the researchers said.

“If you have a massive database of wetland plants like we do in Illinois, if you look at the numbers, you can isolate the species that are the most problematic,” Spyreas said. Five non-native wetland plants are on the “worst offender” list, he said: reed canary grass, a non-native cattail, invasive Phragmites and two European buckthorns.

“If you can eliminate those, you’ve eliminated 90 percent of the non-native wetland species problem,” Spyreas said.

Read the paper: Ecology letters

Article source: University of Illinois at Urbana-Champaign, News Bureau

Image: Greg Spyreas, Michael Jeffords and Susan Post

Native forests make up 1% of the landscape in South Africa but could play a key role in reducing atmospheric carbon and identifying sustainable development practices that can be used globally to counter climate change, according to a Penn State researcher.

“As we think about pathways for reducing atmospheric carbon dioxide concentrations, one of the available approaches is to use the natural world as a sponge,” said Erica Smithwick, professor of geography and director of the Center for Landscape Dynamics at Penn State.

The challenge, according to Smithwick, is to use forests to store carbon while also meeting local community needs. As trees grow, they absorb and store carbon through photosynthesis. Carbon makes up about half of a tree’s mass, but amounts vary by species. To find its carbon stock, scientists use equations based on the tree’s diameter and other variables, like height and wood density, rather than cutting down and weighing each species.

In 2011, Smithwick tagged and measured trees in the Dwesa-Cwebe nature reserve in the Eastern Cape Province with help from students in Penn State‘s Parks and People study abroad program. She remeasured the trees five years later while in South Africa on a Core Fulbright U.S. Scholarship and analyzed the forests’ carbon content. The results of the study, one of the first to quantify carbon content in Africa, appear in a recent issue of the journal Carbon Management.

Smithwick found that the coastal, indigenous forests store a moderate to large amount of carbon. They are also a biodiversity hotspot and thus important for conservation. The local communities depend on the forests for resources such as medicinal plants, fuelwood and timber, as well as their spiritual needs, Smithwick added.

“As we move toward the sustainable development of these places, we need to think about how the local communities are able to value and work with these characteristics of the forests,” said Smithwick, who also holds an appointment in Penn State’s Earth and Environmental Systems Institute. “Understanding what is an optimal level of productivity extraction from the natural system so we’re not degrading the system is an area of interest. We’re trying to figure out what the balance between forest productivity and resource extraction is.”

Smithwick noted that the large amount of forest productivity, or how quickly the forests grow, and small amount of human use of forest resources suggest that humans are not negatively influencing the Dwesa-Cwebe forests. She added that access to the nature reserve is limited, and other reserves see more resource extraction.

The South African government manages Dwesa-Cwebe but plans eventually to hand over management of the park to the surrounding local communities. Smithwick said that conservation of the area must integrate human interactions and values into a development model that recognizes how humans can benefit a forest system if managed in a sustainable way.

“We have to recognize the importance of these natural forests and their biodiversity and carbon values, but we also have to situate that in a sustainable development challenge,” said Smithwick, who is also director of the Huck Institutes of Life Sciences Ecology Institute and associate director of the Institutes of Energy and the Environment. “The forest in South Africa is a good case study for how we start to think about balancing these considerations. The lessons learned from this hopefully can resonate to how we think about these challenges in other parts of the world.”

Read the paper: Carbon Management

Article source: Penn State

Image: Erica Smithwick Lab / Penn State

The sweet, starchy orange sweet potatoes are tasty and nutritious ingredients for fries, casseroles and pies. Although humans have been cultivating sweet potatoes for thousands of years, scientists still don’t know much about the protein makeup of these tubers. In ACS’Journal of Proteome Research, researchers have analyzed the proteome of sweet potato leaves and roots, and in the process, have revealed new insights into the plant’s genome.

The sweet potato (Ipomoea batatas, Lam.) is a staple food in some parts of the world, in addition to being used for animal feed and industrial products, such as biofuels. The plant has a surprisingly complex genome, encoding more predicted genes than the human genome. Sweet potato also has a complex chemical composition, with a low protein content in the roots (the part that people eat) and many secondary metabolites in the leaves, making it difficult to extract sufficient quantities of proteins for analysis. Sorina and George Popescu and colleagues wanted to see whether a “proteogenomics” approach — analyzing both protein and genetic data together — could help them gain a better understanding of the compositions of sweet potato roots and leaves.

The team extracted proteins from root and leaf samples using two different methods and cut them into peptides, which they analyzed with liquid chromatography and mass spectrometry. The researchers identified 3,143 unique proteins from sweet potato leaves and 2,928 from roots. When they compared the proteomic data with the genome of the sweet potato, they identified some regions in the published genome sequence where their data could provide enhanced information. For example, the analysis predicted 741 new protein-coding regions that previously were not thought to be genes. The group says the results could be used to help further characterize and biofortify the tuber.

Read the paper: Journal of Proteome Research

Article source: American Chemical Society

Image: Iva Balk/Pixabay

Wetlands are an important part of the Earth’s natural water management system. The complex system of plants, soil, and aquatic life serves as a reservoir that captures and cleans water. However, as cities have expanded, many wetlands were drained for construction. In addition, many areas of land in the Midwest were drained to increase uses for agriculture to feed a growing world.

Draining wetlands disconnected the natural flow and retention of water, a system that had worked well for millennia. One solution to wetland draining was to rebuild these wetlands in another area (more convenient to humans). These are referred to as “constructed wetlands.” In other cases, constructed wetlands are built to rebuild an area no longer used for agriculture.

How these constructed wetlands are built and managed can make a big environmental impact. Karla Jarecke and researchers from several universities have been studying wetlands’ impact on the greenhouse gas methane.

“Globally, wetlands are the largest natural source of methane to the atmosphere,” says Jarecke. “Methane has a much bigger impact than carbon dioxide on global warming – an impact 25 times greater.”

Both natural and constructed wetlands emit methane. Due to their nature – wetlands are, after all, wet – soil microbes and plants are forced to metabolize under anaerobic conditions. And, this leads to methane production.

The soil microbes are responsible for the production of methane in wetlands. The methane then gets to the atmosphere via diffusion, transport through plant tissue, and the episodic release of gas bubbles. The hydrologic stability of wetland soils, as well as the transport efficiency through plants, can affect how much and how often methane is released from the soil.

“Understanding the conditions under which methane is produced and released in wetlands could lead to solutions to reduce methane emissions,” says Jarecke.

The study focused on two common wetland plants and their potential role in methane emissions: swamp milkweed and northern water plantain. Plants and soils were collected from a constructed wetland in Dayton, Ohio. They were then transported to Lincoln, Nebraska to create wetland mesocosms. The Dayton site had formerly been drained and used for agriculture and was rebuilt as wetland in 2012.

The researchers harvested seedlings of swamp milkweed and northern water plantain from the wetland and transplanted them into soils collected in PVC pipe. They covered individual plants with clear acrylic cylinders during gas sampling. This helped them measure and quantify methane emissions from the soil-plant mesocosms. The study was performed in the summer of 2013.

Besides comparing the emissions of the two plant species, the researchers studied the effects of hydrology – or the saturation of the soil. “While the controls of hydrology and plant species on methane emissions are individually well-studied, the two are rarely studied together,” says Jarecke.

This recent study concluded that water level and saturation influenced methane emissions more than the type of plant species. While methane emissions differed between laboratory mesocosms with water plantain and mesocosms with swamp milkweed, methane emissions did not differ in field mesocosms with each of the two species. In the field, soil saturation had a greater effect on methane emissions.

Finding plant species that reduce microbial methane production could be a key to better wetland management. For example, plants that deliver oxygen to the rooting zone can suppress microbial methane production. In addition, future research is needed to understand how varying soil saturation affects methane emissions. This information could be valuable for designing wetland topography that creates hydrologic conditions for increased carbon storage and reduced methane emissions.

Read the paper: Soil Science Society of America Journal

Article source: American Society of Agronomy

Image: Karla Jarecke

Slow-growing ponderosa pines may have a better chance of surviving longer than fast-growing ones, especially as climate change increases the frequency and intensity of drought, according to new research from the University of Montana.

Researchers found that ponderosa longevity might hinge on the shape of microscopic valve-like structures between the cells that transport water through the tree.

The study, led by UM alumna Beth Roskilly and Professor Anna Sala, was published in the Proceedings of the National Academy of Sciences. The researchers sampled growth rates of ponderosa pine trees of varying ages at two remote sites in Idaho. They also studied structural traits of the trees’ xylem – vascular tissue that transports water and minerals through the wood and provides structural support.

Their findings reveal that some young trees grow quickly while others grow slowly. But old ponderosa pine trees – those older than 350 years – are slow growers compared to younger trees, and these individual trees have always been slow growing, even when they were young.

In contrast to predictions, slow-growing trees, whether old or young, did not produce denser, tougher wood, which might have made the trees more resistant to disease or decay. Instead, a key difference between fast and slow growers resides in a microscopic valve-like structure between the cells that transport water in the wood, called the pit membrane. The unique shape of this valve in slow-growing trees provides greater safety against drought, but it slows down water transport, limiting growth rate.

“Ponderosa pines, like people, cannot have it all,” said Roskilly, the paper’s lead author. “Drought resistance contributes to longevity but also to slow growth. In other words, there is a fundamental tradeoff based on xylem structure. Our study suggests that trees with fast growth become large quickly, which can be beneficial for young trees competing for resources, but they are more vulnerable to drought and can die at earlier ages. On the other hand, trees that grow slowly are more drought resistant, which enhances longevity.”

Roskilly earned her UM master’s degree in organismal biology, ecology and evolution in 2018, and the study is a result of her degree work in UM’s College of Humanities and Sciences.

“Ancient trees are special for many reasons,” said Sala, a professor in UM’s Division of Biological Sciences and an adjunct professor in the W.A. Franke College of Forestry and Conservation. “They are beautiful, they make the highest quality musical instruments, they help maintain diversity, and they store atmospheric carbon in wood for a long time. But the results of this research also suggest they are special because forest managers cannot make just any ponderosa pine tree live for centuries no matter how hard they try. For ponderosa pines to become centennials, their wood must possess this unique structure.”

Other co-authors in the study include UM alumnus Eric Keeling, a professor at the State University of New York; UM alumna Sharon Hood, a research ecologist with the U.S. Forest Service; and Arnaud Giuggiola, a former visiting master’s student from the University of Bordeaux. This project built on dissertation work by Keeling and began as an undergraduate research project started by Roskilly.

Read the paper: PNAS

Article source: University of Montana

Image: Beth Roskilly

On 18 June 2019, the Commission published its assessment of Member States’ draft plans to implement the EU’s Energy Union objectives, in particular the agreed EU 2030 energy and climate targets, as well as technical recommendations on Member States’ National Forestry Accounting Plans.

These plans contain a proposed “Forest Reference Levels”, which act as a baseline for future greenhouse gas emissions and removals from managed forest land.

The JRC played a key role in the development of this concept, which allows assessing the greenhouse gas impact of human action in the forestry sector.

Measuring the impact of human action in the forestry sector

The EU has set a target for reducing its anthropogenic greenhouse gas (GHG) emissions by at least 40% by 2030 relative to 1990.

As explained by Giacomo Grassi, the JRC’s expert on measuring the climate impact of forest management, “it is rather straightforward to measure the impacts of human activities on emissions from, for instance, the energy sector: all emissions are anthropogenic and any reduction of emissions can be claimed as anthropogenic. But in the forestry sector this becomes more challenging”.

Forest trees absorb CO2 through photosynthesis, and therefore mitigate climate change. In the EU, for example, forests offset nearly 10% of total EU GHG emissions.

However, to give the right policy incentives for enhancing our carbon sinks, we need to identify how much of this absorption is due to recent forest management decisions.

“If you plant a tree, continues Giacomo, this is clearly a result of recent human action. However, the CO2 absorption in the majority of existing EU forests is largely affected by natural factors or by management choices done a long time ago, e.g. when your grand-grandfather planted a tree”.

Measuring how much of the current CO2 absorption by forests is due to ongoing human activities has therefore long been a demanding task.

Science-based carbon accounting system for forest management

A JRC-led group of forest experts has developed a new science-based approach to assess the greenhouse gas impact of human action in the forestry sector.

This approach is based on country-specific projected baselines which will be used to measure the GHG impact of future forest activities.

“In other words, says Giacomo, each country calculates how much CO2 would be absorbed by its forests without changing the current management. This sets the baseline, called Forest Reference Level”.

This approach ensures greater environmental integrity and comparability of mitigation efforts across sectors of the economy.

At the same time, it allows to reflect the country-specific forest dynamics, for example if a forest on average is getting older.

Integrating the land-use, land-use change and forestry (LULUCF) sector in the EU climate strategy

This approach was included in the EU Regulation from 2018 incorporating the forest sector in the EU 2030 climate targets.

As required by this Regulation, the EU Member States propose their Forest Reference Levels for the period 2021-2025.

An expert group composed of Member States representatives, technical specialists, NGOs and research organisations was formed to undertake a technical assessment of the plans and the proposed forest reference level.

The JRC played a very active role in facilitating this technical assessment.

The Commission has now issued technical recommendations reflecting the conclusions of the assessment process.

These technical recommendations will form the basis for the revision of Member States’ forest reference levels, which are to be submitted by 31 December 2019.

The Commission will then adopt delegated acts containing the final forest reference levels for the period 2021 and 2025 by 31 October 2020.

Article source: European Commission, Joint Research Centre (JRC)

Image: pixel2013/Pixabay

The myth that modern wheat varieties are more heavily reliant on pesticides and fertilisers than older varieties has been debunked by new research.

The University of Queensland’s Dr Kai Voss-Fels said modern wheat varieties have out-performed older varieties in side-by-side field trials under both optimum and harsh growing conditions.

“There is a view that intensive selection and breeding, which has produced the high-yielding wheat cultivars used in modern cropping, has also made them less resilient and more dependent on chemicals to thrive,” Dr Voss-Fels said.

“However, the data published today unequivocally shows that modern wheat out-performs older varieties, even under conditions of reduced amounts of fertilisers, fungicides and water.

“We also found that genetic diversity within the relatively narrow modern wheat gene pool is rich enough to potentially generate a further 23 per cent increase in yields.”

The researchers compared 200 wheat varieties, essential to agriculture in Western Europe over the past 50 years, under contrasting input levels of mineral fertilisers and plant protection chemicals.

Dr Voss-Fels said the findings might surprise some farmers and environmentalists.

“Quite a few people will be taken aback by just how tough modern wheat varieties proved to be, even in harsh growing conditions, such as drought, and using less chemical inputs.”

Dr Voss-Fels and Professor Ben Hayes at the Queensland Alliance for Agriculture and Food Innovation (QAFFI) developed a method to match the performance differences with the different varieties’ genetic make-up.

“This genetic information allows us to take the discovery to the next level,” Dr Voss-Fels said.

“We want to develop breeding strategies to bring together favourable alleles in new cultivars in the shortest possible time.”

“We are using artificial intelligence (AI) algorithms to predict the optimal crosses needed to bring together the most favourable segments as fast as possible.”

Global yields of the world’s most important food crop have been reduced by droughts in recent years.

Dr Voss-Fels said with more climate risk anticipated, the hardiness of modern wheat varieties was an issue of global significance.

“Increased breeding efforts are needed to enhance the resilience of wheat varieties to challenging environmental conditions.”

Dr Voss-Fels said the study’s findings could also have important implications for raising the productivity of organic cropping systems.

Professor Rod Snowdon of the Justus-Liebig-University Gießen (JLU) and collaborators from seven other German universities led the research.

Read the paper: Nature Plants

Article source: University of Queensland

Image: University of Queensland

A grape variety, still used in wine production in France today, can be traced back 900 years to just one ancestral plant, scientists have discovered.

With the help of an extensive genetic database of modern grapevines, researchers were able to test and compare 28 archaeological seeds from French sites dating back to the Iron Age, Roman era, and medieval period.

Utilising similar ancient DNA methods used in tracing human ancestors, a team of researchers from the UK, Denmark, France, Spain, and Germany, drew genetic connections between seeds from different archaeological sites, as well as links to modern-day grape varieties.

It has long been suspected that some grape varieties grown today, particularly well-known types like Pinot Noir, have an exact genetic match with plants grown 2,000 years ago or more, but until now there has been no way of genetically testing an uninterrupted genetic lineage of that age.

Dr Nathan Wales, from the University of York‘s Department of Archaeology, said: “From our sample of grape seeds we found 18 distinct genetic signatures, including one set of genetically identical seeds from two Roman sites separated by more than 600km, and dating back 2,000 years ago.

“These genetic links, which included a ‘sister’ relationship with varieties grown in the Alpine regions today, demonstrate winemakers’ proficiencies across history in managing their vineyards with modern techniques, such as asexual reproduction through taking plant cuttings.”

One archaeological grape seed excavated from a medieval site in Orléans in central France was genetically identical to Savagnin Blanc. This means the variety has grown for at least 900 years as cuttings from just one ancestral plant.

This variety (not to be confused with Sauvignon Blanc), is thought to have been popular for a number of centuries, but is not as commonly consumed as a wine today outside of its local region.

The grape can still be found growing in the Jura region of France, where it is used to produce expensive bottles of Vin Jaune, as well as in parts of Central Europe, where it often goes by the name Traminer.

Although this grape is not so well known today, 900 years of a genetically identical plant suggests that this wine was special – special enough for grape-growers to stick with it across centuries of changing political regimes and agricultural advancements.

Advanced knowledge

Dr Jazmín Ramos-Madrigal, a postdoctoral researcher from the University of Copenhagen, said: “We suspect the majority of these archaeological seeds come from domesticated berries that were potentially used for winemaking based on their strong genetic links to wine grapevines.

“Berries from varieties used for wine are small, thick-skinned, full of seeds, and packed with sugar and other compounds such as acids, phenols, and aromas – great for making wine but not quite as good for eating straight from the vine. These ancient seeds did not have a strong genetic link to modern table grapes.

“Based on writings by the Roman author and naturalist, Pliny the Elder, and others, we know the Romans had advanced knowledge of winemaking and designated specific names to different grape varieties, but it has so far been impossible to link their Latin names to modern varieties.

“Now we have the opportunity to use genetics to know exactly what the Romans were growing in their vineyards.”

Roman seeds

Of the Roman seeds, the researchers could not find an identical genetic match with modern-day seeds, but they did find a very close relationships with two important grape families used to produce high quality wine.

These include the Syrah-Mondeuse Blanche family – Syrah is one of the most planted grapes in the world today – and the Mondeuse Blanche, which produces a high quality AOC (protected regional product) wine in Savoy, as well as the Pinot-Savagnin family – Pinot Noir being the “king of wine grapes”.

Further back in time

Dr Wales said: “It is rather unconventional to trace an uninterrupted genetic lineage for hundreds of years into the past. Instead of exploring broad patterns in genetic ancestry, as in most ancient DNA projects, we had to think like forensics scientists and find a perfect match in the database.

“Large databases of genetic data from modern crops and optimized palaeogenomic methods have vastly improved our ability to analyse the history of this and other important fruits.

“For the wine industry today, these results could shed new light on the value of some grape varieties; even if we don’t see them in popular use in wines today, they were once highly valued by past wine lovers and so are perhaps worth a closer look.”

The researchers now hope to find more archaeological evidence that could send them further back in time and reveal more grape wine varieties.

Read the paper: Nature Plants

Article source: University of York

Image: PIRO4D / Pixabay

We’ve all heard about bacteria that are becoming resistant to multiple types of antibiotics. These are the so-called superbugs perplexing and panicking medical science. The plant analogue may just be waterhemp, a broadleaf weed common to corn and soybean fields across the Midwest. With resistance to multiple common herbicides, waterhemp is getting much harder to kill.

In a new study from the University of Illinois, scientists document waterhemp’s resistance to yet another class of herbicides, known as Group 15s. The study provides the first documentation of a non-grass plant to be resistant to Group 15 herbicides.

There are many herbicides on the market, but they all fall into one of 16 classes describing their mode of action (MOA), or specific target in the plant that the chemical attacks. Because of various regulations and biological realities, a smaller number of herbicide MOAs can be used on any given crop and the suite of weeds that goes along with it. Historically, about nine have been useful for waterhemp – and now the weed appears to be resistant to at least seven.

“In some areas, we’re one or two MOAs away from completely losing chemical control of waterhemp and other multiple-herbicide-resistant weeds,” says Adam Davis, head of the Department of Crop Sciences at Illinois and co-author on the study. “And there are no new herbicide MOAs coming out. There haven’t been for 30 years.”

Illinois weed scientist and co-author Aaron Hager adds, “We don’t want to panic people, but farmers need to be aware this is real. It continues on with the challenges we’ve warned people about for years.”

The research team tested the effectiveness of soil-applied Group 15 herbicides in a Champaign County population already resistant to five MOAs. They applied eight Group 15 formulations in the field at their label rates, and chose three – non-encapsulated acetochlor (Harness), S-metolachlor (Dual Magnum), and pyroxasulfone (Zidua) – for a rate-titration experiment in which the herbicides were applied at one-half, one, two, and four times the label rate.

The eight Group 15 products varied in their effectiveness, with encapsulated acetochlor (Warrant), S-metolachlor, metolachlor (Stalwart), and dimethenamid-P (Outlook) performing the worst. These products provided less than 25% control 28 days after application and less than 6% control 14 days later.

Of the rate-titration experiment, Hager says, “We found we could apply significantly higher than the labeled dose and still see resistance.” For example, S-metolachlor provided only 10% control at the standard label rate, 20% at 2x the label rate, and 45% at 4x the label rate.

Hager says farmers might not notice the poor performance of these soil-applied pre-emergence herbicides because waterhemp germinates continuously throughout the season. When a weed pops up mid-season, it’s hard to tell exactly when it emerged and whether it was exposed to residual soil-applied herbicides.

“If you think about how you use these products, rarely do they last the entire year. They’re very dependent on environmental conditions to work effectively. It could be too wet or too dry. Generally speaking, you have some weed escape. But many farmers would chalk it up to these weather issues. If you’re not thinking about it, you could very easily overlook resistance,” Hager says.

To confirm results from the field, the team performed a dose response test in the greenhouse. In that test, four waterhemp populations – three with resistance to multiple herbicides and one that is sensitive to all herbicides – were dosed with increasing levels of S-metolachlor, acetochlor, dimethenamid-P, and pyroxasulfone. Populations from Champaign County and McLean County survived higher levels of the Group 15 herbicides than the other populations.

Hager suspects the plants are breaking the chemicals down before they cause damage, a trick known as metabolic resistance. All organisms can turn on cellular defenses against toxins, but it is rather worrisome when weeds and other undesirable pests use their biology against human interventions.

“As we get into the era of metabolic resistance, our predictability is virtually zero. We have no idea what these populations are resistant to until we get them under controlled conditions,” Hager says. “It’s just another example of how we need a more integrated system, rather than relying on chemistry only. We can still use the chemistry, but have to do something in addition.

“We want farmers to understand that we have to rethink how we manage waterhemp long term.”

Read the paper: Weed Science

Article source: University of Illinois

Image: Aaron Hager with waterhemp. Photo by L. Brian Stauffer