Weed Wednesday

Are You Spraying The Right Weeds? Apps Can Help

Thu, 22 Sep 2022 02:03:41 GMT

Attacking weeds early on is key to stopping them from spreading. In order to do that, you need to know what weeds you’re up against. There are several apps available to distinguish which weed you’re fighting, but how accurate are they?

Researchers at Michigan State University (MSU) have been measuring app identification accuracy for four years. This year, the researchers tested eight apps:

1. Picture This
2. Planet Net
3. PlantStory
4. LeafSnap
5. iNaturalist
6. Seek
7. PlantSnap
8. GardenAnswers

All the apps tested used photo recognition software to identify plants, but some tested in the past required more descriptive input from the user, similar to traditional plant keys. The students tested numerous plants at various growth stages.

They say the apps correctly identified anywhere from 11% to 67% of the plants they photographed, while 25% to 80% of the images were partially identified correctly.

According to the researchers, Picture This—found on the Apple App Store and Google Play—came out on top, successfully identifying 67% of the 130-plants photographed. This app has reigned champion in the test for four years in a row.

Grassy varieties proved the most challenging for many apps, with less than 10% accuracy. According to MSU, grasses are difficult to identify using whole plant images, as close inspection of fine structures is often required for grass identification.

MSU researchers say these apps are a great starting point, but it’s important to double-check the results with a trusted source.

Late-Maturing Soybeans Might Reduce Weeds, Based on Research from Illinois

Thu, 22 Sep 2022 02:03:41 GMT

Are weed pressure and changes in the climate unsurmountable? A new study from the University of Illinois looked at climate variability, yield losses and potential relief measures.

Researchers analyzed several factors leading to soybean yield loss in a 26-year herbicide study conducted across the state of Illinois.

Based on their findings, the researchers say inadequate late-season weed control—what they define as any application below 76%—was responsible for a 48% loss in yields. When drought and heat hit, the research showed high levels of weed control also didn’t stop significant yield loss to weeds.

The researchers say with the vast majority of U.S. soybean growing regions developing into a drier, warmer climate along with herbicide resistance, soybean yields will continue to decrease unless significant improvements are made to weed management systems.

“You need almost perfect weed control to avoid yield losses in hot, dry conditions. Unfortunately, we have a lot of weed escape in soybean,” says Marty Williams, USDA-ARS ecologist and affiliate professor in the Department of Crop Sciences at Illinois.

Martin Williams, the lead author of the study, says later-maturing soybeans might be able to reduce the risk of incomplete weed control in a more variable climate.

Science at Work

A new weed control system may help to fight weeds, particularly broadleaf weeds and grasses.

Bosch high-tech cameras and Xarvio agronomic intelligence are combined in the Smart Sprayer capable of photographing weeds at more than 1,000 per second.

With cameras spanning the entire operating range of the sprayer, the software and hardware identify the weed, signal a set of nozzles to spray the exact product needed on the weeds, and records the information in real time for farmer review within milliseconds.

The joint venture between BASF and Bosch is in the proof-of-concept stage for U.S. growers. The companies hope to have a limited introduction in 2023.

Read more on sprayers:
> Joint Venture Brings ‘Smart Spraying Solution’ To Farmers

Giant Salvinia’s Hidden Uses Unlocked by LSU Students

Thu, 05 May 2022 13:59:13 GMT

Weeds aren’t just a problem on land, but also in water. One weed continues to pose a major problem in Louisiana waterways.

It is far too common to see waterways in Louisiana clogged by giant salvinia, an invasive aquatic plant native to South America. Chris Mudge, Louisiana State University (LSU) adjunct professor of plant, environmental and soil sciences, has been studying aquatic weeds for several years and has seen just how damaging the plant is.

Upcycle Opportunities

LSU AgCenter Reporter Craig Gautreaux says students in art class are developing at an alternative use for the invasive plant.

“Initially we see a few plants, then it becomes a monoculture, meaning there’s no other plants, native or invasive, that can hang on,” says Mudge. “Then the plant stops things like navigation. Irrigation is blocked. So those homeowners and farmers or nursery owners can no longer use the water anymore.”

Mudge and others have been looking at ways to control giant salvinia. Now, Mudge and Leslie Koptcho, an art professor at LSU, are looking at an alternative use for the noxious plant — making paper for student art projects.

“Instead of stockpiling them and piling them up on the ground and making compost, which they have low nutritional value, why not take them and find alternative uses,” Mudge says. “And that was to make paper out of it.”

Worth the Wait

The papermaking class uses a variety of invasive plants found in Louisiana. It can take several days to make the paper because of the many steps involved, but Koptcho believes using them can shed light on the problems the plants create.

“We really wanted to use invasives and feature invasives this time because — one, it’s part of my research,” says Koptcho. “We really want to look at those aquatic plants that are unique to the region, and they’re posing a real problem for us in Louisiana.”

Koptcho says the class teaches her students about these problems, and in turn, the students can educate others through their art. While she understands upcycling may not solve the problem, Koptcho believes her class is creating awareness through artwork.

More on weeds:
> 7 Tips to Manage Herbicide Supplies
> Late-Maturing Soybeans Might Reduce Weeds, Based on Research from Illinois
> Blue Light: A Proven Weed Destroyer
> From Sawdust to Herbicide Drift Solution

7 Tips to Manage Herbicide Supplies

Thu, 28 Apr 2022 17:14:06 GMT

Post-emergent herbicide supplies can be hard to find this year. To overcome this challenge, make a plan and consider a new approach to weed management.

You might end up using some products for the first time in years or ever. Or, you might need to lean more heavily on soil-applied pre-emergent products.

“We can start out with a good foundation program,” says Christy Sprague, Michigan State University Extension weed specialist. “That will help us to not rely so heavily on those postemergent herbicides that are probably going to be in short supply this year.”

This season calls for staying flexible and coming up with a plan A, B or even C.

“We’re telling customers in the 21 days after planting to have residual post-application out there,” says Scott Stout, Co-Alliance’s protection and seed business manager. “We can’t rely on trying to clean it up like we have in the past. We’re still waiting for some of these key chemistries to come off the line.”

These specialists suggest spraying any breakthrough weeds early — while just 1" to 4" tall — to help keep weeds in check and maximize the effectiveness of the postemergent pass.

Here are management tips to consider implementing this spring:

1. Layer your Approach to Herbicides

Use a soil-applied herbicide around planting and prior to emergence. Add other active ingredients that can target specific problem weed species. Twenty days later, use a postemergence herbicide while weeds are small (shorter than 4").

2. Don’t Cut Rates
Research shows dropping rates drives weed resistance. Even non-resistant weed escapes that go to seed can remain in the soil bank for years.

3. Manage Without Herbicides
Some farmers might choose to implement a mechanical tillage pass rather than a spring burndown. Cover crops can be an option since they hold back weeds. Plant in narrower rows or at higher populations to reach canopy cover more quickly. Soybean populations that get too high, however, tend to see more lodging later in the season.

4. Dial In Perfection
Take time to calibrate your sprayer, make appropriate adjuvant or surfactant selections and then work during appropriate humidity, sunlight intensities, temperatures and time of day. These strategies can make a world of difference in the effectiveness of a product.

5. Add More Water
It takes more time to use but increasing the amount of water sprayed per acre can improve coverage and efficiency. Make sure you’re using sufficient water, per the label, especially for systemic herbicides.

6. Understand Residuals and Rotation
Make sure you factor in chemistry residuals and soil carryover when using a diverse cropping rotation. Different soil types can affect residual performance in different ways.

7. Focus on Plant Health
Maintaining early and midseason fertility and vigor helps plants grow more quickly and shade out weed competition. That means keeping an eye out for plant diseases and defoliating insects. Biostimulants or growth regulators can also be useful in pushing vegetative elongation and biomass growth.

Read More: 16 Ways to Boost Results from Glyphosate

From Sawdust to Herbicide Drift Solution

Thu, 21 Apr 2022 20:30:31 GMT

Adjuvant based on wood waste reduces herbicide drift

By Fred Miller and Rhonda Brooks

Today’s sawdust could be tomorrow’s solution to controlling herbicide drift, thanks to work by two young entrepre-neurs, Joseph Batta-Mpouma and Gurshagan Kandhola.

Their research, while students at the University of Arkansas, has led to a patent-pending, product formulation based on biodegradable cellulosic nanoparticles made from wood waste. The nanoparticles can bind with herbi-cides and prevent off-target movement.

Nanoparticles, as the name implies, are minuscule and range between 1 to 100 nanometers in size. One nanometer is one-billionth of a meter.

For reference, a sheet of paper is about 100,000 nanometers thick. A strand of human DNA is 2.5 nanometers in di-ameter.

HOW IT WORKS

Batta-Mpouma and Kandhola’s plan is for farmers to be able to use the product, recently trademarked as

BioGrip, as an adjuvant in herbicide tank mixes.

BioGrip adds weight to herbicide droplets, causing them to fall faster and more directly on target during field ap-plications. It also prevents volatilization of herbicide active ingredients, so they stay put on the weeds.

Batta-Mpouma and Kandhola are working on the commercial application of the BioGrip through their recently launched company, CelluDot.

The pair developed the product formulation in cooperation with Jin-Woo Kim, professor of biological and agricul-tural engineering for the Arkansas Agricultural Experiment Station, which is the research arm of the University of Arkansas System Division of Agriculture.

FROM WASTE TO TREASURE

The raw material being used to develop the product is wood waste that’s readily available from timber companies, Kim says.

The U.S. timber industry generates 97 million dry tons of waste annually, reports the Department of Energy.

Beyond wood waste, Kim is looking at how rice hulls, other grain husks and straw can be used to develop similar technologies.

“They all have the added advantage of being biodegradable,” he says.

No petroleum-derived surfactants are being used in the BioGrip formulation, enhancing its environmentally friendly footprint.

Kim says the technology used to create BioGrip has many potential applications. In addition to agricultural uses, researchers are evaluating the use of nanoparticles in biomedical and manufacturing industries.

BioGrip is in the early stages of development. The team has received several grants, but commercialization timing has not been determined.

Blue Light: A Proven Weed Destroyer

Thu, 21 Apr 2022 20:30:06 GMT

Plants need light to survive and grow, but too much light can be a bad thing. Scientists in Ohio are experimenting to unlock weed-destroying possibilities in blue light.

Global Neighbor, Inc. (GNI) , a tech company aimed at harnessing Directed Energy (DE), is using blue light and heat to kill weed seeds on the way through the combine.

“We use short durations of light at high intensity to alter a plant’s growth,” says Jon Jackson, president of GNI “We can hinder a weed seed’s growth, or we can make that seed grow faster.”

The blue light concept has been several years in the making, as Jon Jackson says his team was given a Small Business Investment Research (SBIR) grant from Edwards Air Force Base, with an objective to control, plant and defoliate plants without using chemicals, in a way that won’t disturb the desert soil crust.

High Light Research

Tumbleweed seeds in the California desert were assigned as the initial blue light objective, until a farmer in Iowa caught wind of the research and asked for help in fighting waterhemp.

GNI’s team flipped the switch on blue light in waterhemp, thinking “if you can kill tumbleweed seeds, you can probably kill other seeds as well.” Their hunch was right.

“We found that if we can warm a seed up to a certain temperature and then flood it with blue light, we can damage the cells that control the radical growth so that the seed won’t become a plant,” says Jon Jackson.

GNI put the science to work in a system that bolts onto combines, destroying weed seeds on their way out the back of the machine.

“As the years go on, you’re putting less weed seed back into the field because more and more of them are becoming disabled,” says Patrick Jackson, product manager at Global Neighbor.

GNI intends to move their prototype to testing phase during wheat harvest next month.

Low Light Findings

Jon Jackson says his team found that if they dial back the blue light, but warm up the seed, they can get the seed up and out of the ground at a faster rate.

Cadance Lowell, professor of plant science at Central State University has been testing blue light growth rates at:
• Two seconds
• Five seconds
• 10 seconds

Lowell’s team is researching ways to build a system that will replace chemicals for cover crop burndown.

“In this experiment, there was some damage done to the two-second crop,” she says. “But by the time you get to the 10-second treatment, you can see that the dry grass is dead.”

Lowell says she is “amazed and excited” to see advancements with blue light and looks forward to new opportunities from her team’s research.

More on weeds:
> From Sawdust to Herbicide Drift Solution
> Smooth Bedstraw: Pretty to Look At, Problematic in the Pasture
> Late-Maturing Soybeans Might Reduce Weeds, Based on Research from Illinois

Hit the Weed Window or Pay a Price

Mon, 14 Feb 2022 14:52:11 GMT

Residual reliance as weed resistance builds

Planting with no pre-emerge herbicides or residuals is a dance through a minefield, particularly in an age of herbicide resistance. Far from formulaic, every grower’s approach to preplanting chemical application is contingent on specific circumstances, but a common thread remains: Hit the window or pay a price.

THE BACKBONE

On most Midwest farms, multiple weed species force producers into a wallet- draining game of whack-a-mole, with the most prolific early spring and summer annuals centered on marestail, giant ragweed, waterhemp, common lambsquarter and giant foxtail.

“Looking at our present tools, we’ve become so much more limited in terms of postemerge herbicides,” says Bill Johnson, a weed scientist with Purdue University Extension. “Many weeds have developed resistance to the main postemergence herbicides.”

Residuals were once the backbone of weed control programs, and Johnson hopes for a return.

“I’d like to see us going back to residuals like we used to do, and then using postemerge to clean up escapes,” he says.

With a baseline focus on marestail, waterhemp and lambsquarter, Johnson cites an extensive list of premix options, but draws down on three key chemicals: sulfentrazone, flumioxazin and metribuzin.

“Bottom line, if you have those three weeds, at least use one of those active ingredients,” he says. “There are certainly other products with residual activity on something like giant ragweed, provided the ragweed isn’t ALS-resistant.”

When does Johnson recommend spray activity? “For a residual, ideally we want to see that put down the day of or shortly after planting.”

The overwhelming majority of Ohio soybean fields are sprayed with pre-emerge herbicides, initially driven by an upswing in marestail, according to Mark Loux, a weed scientist with Ohio State University Extension.

“I’d say we once got down to about 40% of our soybean acres getting pre-emerge, but now we’re back to the far majority getting a pre-treatment,” he says. “We’ve got better post options, but the bottom line is we’ve got weed species that are just not manageable without pre-emerge herbicides.”

The biggest resistant weed issues in Loux’s geography come from giant ragweed, common ragweed, marestail, waterhemp and Palmer amaranth. “Take away residuals and you get big problems with lambsquarter,” he says. “Some weeds are relatively easy to control pre, but much harder to control post.”

A BALANCING ACT

The application window, Loux says, is a balancing act. “Go on too early and you reduce longevity into the season. If you plant beans at the beginning of May, and put on a pre in mid-April, you really want residual activity into June, and if you apply too early, you squander some of that reach into June.”

If you’re going after a specific driver weed like giant ragweed, Loux says, then the only herbicides with residual activity are premix products that contain chlorimuron, cloransulam or imazethapyr.

“Something like metribuzin is not strong enough by itself, and we always add something else,” he says.

Loux warns about the possibility of plant injury. “We can put certain products on at planting that cause injury, but there was less potential for that back when we put them on a week or two ahead. To me, that is on the seed companies and the companies that sell those traits. They tell people they can apply anytime they want because you don’t have to wait, but if you put them on after planting, that increases your potential for crop injury.”

As with all chemical decisions, the financial factor weighs heavy. “Look at waterhemp,” Loux says. “It gets control from a residual in the post. Where are you going to pull the trigger and how are you going to divide your chemical dollars between pre and post? That’s a tough choice.”

How a Secret Seed Society at Michigan State Continues to Uncover Weed Seed Answers 142 Years Old

Wed, 26 Jan 2022 22:26:40 GMT

Lansing, Mich., has a rich history of research, with one weed seed project more than 140 years old. And for the past 30 years, Dr. Frank Telewski has been a part of history at Michigan State University.

“I just grew this passion for plants,” says Telewski.

His fascination with growing plants became an obsession as he grew older, as that obsession was fueled even more when he stepped into history in the 1980s when Telewski was asked to be part of a project more than a century old.

“Professor Beal started the experiment back in 1879,” says Telewski.

For 142 years, a secret seed society at Michigan Sate uncovered one of the world’s oldest science experiments.

“The question was, ‘how long can seeds remain viable in the soil, and particularly wheat seeds’ because back in 1879, the latter part of the 19th century, we didn’t have herbicides, we didn’t have high-tech tractors and plows for tilling and cultivating,” Telewski adds.

Professor Beal, the namesake of the tradition, had one burning question about weeds.

“Professor Beal, being very much involved with agriculture here in the state and in the country, set out to answer this question to know how long the weed seed remains viable,” says Telewski.

With that question in mind, Beal gathered 21 different species of annual and biannual weeds, and collected the seeds.

“And what he would do is count out 50 seeds of every species and mix them in with a sandy mix and then fill up 20 bottles with the same mix of sand and the same number of seeds. And his plan was to excavate and get a bottle every five years,” Telewski explains.

Those bottles were then buried in a secret location in the fall of 1879.

“Then, he opened the bottle, he checked the contents, spread it out, put it in the greenhouse and recorded what germinated,” Telewski says.

After Beal retired in 1910, the experiment lived on. And instead of every year, today the bottles are uncovered only once every 20 years.

“They’re just little time capsules of biology that are over 100 years old. And that to me is the fantastic thing,” says Telewski.

Only a handful of people know just where the secret seed spot is on campus. Just last year, a team of five was tapped to continue the tradition and dug up a bottle in April 2021.

“We excavate in the very early morning hours, and there are a couple of reasons for that. We don’t want to attract a lot of attention to where the seeds are buried. We don’t want curiosity seekers to know where the bottles are, so we like to try to keep that under wraps. The other thing is that sunlight can be a trigger for germination,” says Telewski.

Carefully excavated, just like Beal had done 142 years ago, the team took the seeds to the growth chambers and spread them out.

“And then you wait, which usually, seven to 10 days is how long it takes usually for a seed to germinate,” he says.

After seven to 10 days, history started to sprout at Michigan State last spring.

“It’s just so rewarding and exciting to actually be holding a plant, to actually see this,” says Telewski. “When the first cotyledon came up out of the soil and germinated, and you realized the last person to touch this plant when it was a seed was professor Beal 140-plus years ago,” he says.

Out of the 21 weed species originally buried, only one is a survivor today—a Verbascum variety commonly called the “Great Mullein.”

“Talk about a survivor. I mean, this is a plant that’s now survived in the soil for over 140 years. And we still get a relatively high germination rate. You’ll get 20 of the original 50 seeds germinated, so that’s a 40% germination rate. In 2000, we had a 48% germination rate. That’s incredible.”

Telewski retired this past fall from Michigan State University, and he hopes the experiment doesn’t just live on, but is amplified by what uncovering more answers this historic seed bank can provide.

“We understand the gravity of the situation. This is bigger than any of us. We’re literally standing on the shoulders of giants. And it’s a wonderful honor opportunity to be involved in this experiment, it’s historic,” he says.

Combining Ingredients To Tackle Tough Weeds

Wed, 05 Jan 2022 21:43:48 GMT

Help can’t arrive fast enough for corn and soybean farmers who routinely battle tough weeds. Here’s a look at three products manufacturers plan to market for weed control in the near term.

BAYER CROP SCIENCE

PREMIX: Convintro
TYPE OF WEEDS: Palmer amaranth (pigweed) and waterhemp
PROPOSED RELEASE DATE: 2023

Convintro features diflufenican, a Group 12 molecule, and will be used in both corn and soybeans.
In soybeans, Bayer plans to package diflufenican with metribuzin (Sencor) and flufenacet to boost weed control.
In corn, diflufenican will be paired with an HPPD inhibitor to boost weed control.

“Convintro targets a site of action in plants that differs from herbicides U.S. growers commonly use.” ~Frank Rittemann, Bayer product manager

CORTEVA AGRISCIENCE

PREMIX: Resicore XL
TYPE OF WEEDS: Up to 75 broadleaf weeds and grasses in corn
PROPOSED RELEASE DATE: 2022

It features acetochlor (Group 15), clopyralid (Group 4) and mesotrione (Group 27).
The premix can be used preplant, preemergence and postemergence – including in corn 11" or larger.
It includes encapsulated acetochlor for enhanced crop safety.

“Corteva is taking advantage of every opportunity it can to look at current modes of action as well as different active ingredients to help farmers.” ~Brandon Walter, Corteva U.S. product manager

SYNGENTA

PREMIX: Acuron GT
TYPE OF WEEDS: Primarily
broadleaf weeds in corn
PROPOSED RELEASE DATE: 2022

It features glyphosate (Group 9), s-metolachlor (Group 15), bicyclophyrone (Group 27) and mesotrione (Group 27).
Long-lasting residual allows for early post-emergence use (before weeds reach 4" in height) for optimum yield protection.
Flexibility allows use in up to 30"-tall corn, in case of a wet spring.

“Its higher-level control of large-seeded broadleaves such as giant ragweed, morningglory and cocklebur, and pigweed species like Palmer amaranth and waterhemp, really sets Acuron GT apart from all other post-emergence-plus-residual herbicides.” ~Ryan Lins, Syngenta research & development scientist

Focus on MOA and SOA to Improve Weed-Control Outcomes

Wed, 05 Jan 2022 21:24:04 GMT

As weeds resistant to current herbicide technology continue their march across U.S. fields, farmers can slow or stop their progress by putting together a management program that takes into consideration herbicide site of action and mode of action. While the terms are often used interchangeably, they are not the same processes.

Bryan Young, Purdue University weed scientist explains: Mode of Action (MOA) is the name for the process the herbicide uses to control the weed. Site of Action (SOA) is the location within the plant where the herbicide impacts the weed’s development process.

“So, site of action is ‘where’ and mode of action is ‘how,’” Young says.

Understanding the where and how of herbicide active ingredients can help you address weeds and manage your budget more effectively. That understanding can also help you avoid using the same technology repeatedly in a field, which can contribute to the very resistance problems you’re trying to avoid.

Bob Hartzler, Iowa State University Extension weed scientist offers this example as a for instance: “A triazine herbicide (e.g. atrazine, metribuzin) interferes with photosynthesis by binding to the D1 protein involved in photosynthetic electron transfer. Thus, the site of action for triazines is the D1 protein, whereas the mode of action is disruption of photosynthesis.”

Dig into the details. Manufacturers increasingly package multiple herbicide active ingredients in branded premixes to control tough weeds—especially those weed species with multiple herbicide resistance, such as Palmer amaranth and waterhemp. That means you may have to dig a bit deeper to determine what – and how many – SOAs and MOAs you’re using in the field.

The Weed Science Society of America (WSSA) has a numbering system that classifies individual herbicide active ingredients according to their SOA. Tapping into this information can help you build a weed-control program that features a variety of herbicides and tackles weeds in multiple sites.

The WSSA updated its number system just this past May, so it’s current for herbicides in the marketplace now. You can access the system here: https://wssa.net/wssa/weed/herbicides/

Most herbicide labels specify the SOA with a unified logo. Check with your retailer or company sales representative if product labels don’t provide that information.

Hartzler adds a reminder that while herbicides are still useful tools against weeds, don’t overlook the opportunity to include other tools and practices that can improve your control efforts, including crop rotation, cover crops and, yes, even tillage.

Tackle Tough Weeds in Pastures Like you Would in Corn and Soybeans

Let Nature Target Weeds with Bioherbicides

Be Aware of Purchasing Livestock Feed Containing Weed Seeds

Seeds, Weeds and Weather