Manitoba’s provincial weed specialist, Tammy Jones, says producers are already starting from behind on weed control this year, thanks in large part to harvest conditions last fall.

Why it matters: Seeding is stressful enough as is, but farmers this year are also expecting both increased weed pressure and a tight timeline to get down the fertilizer they missed out on last fall.

Some fields were still covered in snow March 31, the same day that Jones posted a picture of a growing kochia seedling, taken by a local agronomist in a field near Winkler, on social media.

The weed has garnered a lot of attention in recent years. Manitoba’s dry weather in 2018 and much of the growing season in 2019 helped proliferate the weed throughout the province, while municipalities reporting glyphosate-resistant kochia has steadily risen to a dozen by 2018 (seven more than in 2016). A survey done that same year found that 59 per cent of the 297 plants tested were resistant to herbicide in some way.

“Kochia, I think, maybe surprises some people, but it doesn’t take much warmth before it starts to germinate,” Jones said. “Fifty growing degree days need to accumulate. It doesn’t take much when you have a 10° day here or a 5° day there for kochia to germinate.”

Both kochia and lamb’s quarters share that short spring turnaround, Jones added.

Manitoba’s looming weed problem is yet another legacy of Manitoba’s “harvest from hell.” Wet conditions in late 2019 forced farmers to leave hundreds of thousands of acres unharvested, as well as leaving much of the province’s normal fertilizer, tillage and weed control passes undone.

Jones expects that to be a problem this spring. On top of last fall’s limited control, those same wet conditions left favourable moisture for early weeds, she said, as well as a prime opportunity for volunteer crop. Farmers likely lost more grain than normal last year given the tough crop and rush to get harvest in, and those seeds may come back to haunt them this spring, she noted.

“I would anticipate that we will see a number of weeds that are having a great time,” she said.

Farmers should expect a harder fight against winter annuals in particular, according to Jones. Weeds that winter as rosettes are already greening, she said, and may actually begin flowering within a few weeks.

“Any of the winter annuals like stinkweed and shepherd’s purse and flixweed, we can see that they are starting to green up and get ready to grow,” she said. “And then Canada thistle, dandelion, foxtail barley, some of those perennials like quackgrass as well — starting to see those green up as well, and they’ll get a head start on a lot of the crop.”

The spring so far has also been friendly to weeds, she said, save a late dump of snow.

Temperatures tipped consistently above freezing in the last week of March before falling in early April, along with the arrival of over 10 centimetres of snow over parts of Manitoba. Temperatures were expected to jump between the near double digits and near freezing for the first two weeks of April, according to Environment and Climate Change Canada.

Getting ahead

Farmers may take the chance to get a jump on early weed identification.

The province has typically held weed seedling identification days each year, although the season’s first weeds have typically passed the seedling stage by the time of the event. That will not be the case if producers take an early walk in the field.

Weeds are, however, sometimes difficult to identify before the two-leaf or four-leaf stage, Jones said.

“That’s usually an important time as well, because that’s when you’re looking at, ‘how many days do I have until I can make a herbicide application that’s going to be really effective controlling that stage of growth with that particular weed.’”

The same rosette weeds that Jones identified as an early threat this year are also at high risk of mistaken identity, attendees were told at one such seedling identification day in 2018.

The province’s weed seedling identification guide is currently out of print, according to the Manitoba Agriculture and Resource Development website, although a new version was expected in 2020.

Finding hours

Farmers expect weed issues to complicate what was already going to be a more complicated spring. Fall conditions have also set fertilizer plans in disarray, as little fall fertilizer was applied. Suppliers also face the new reality of the COVID-19 pandemic, which has led to questions over timely input shipments.

Spring weed control adds yet one more thing for producers to take care of before actually getting seed in the ground, Jones acknowledged.

“It’s going to be a choice, but it can’t mean that we just ignore the weeds and wait for that to be an in-crop application, because for a lot of those weeds that start so early, by the time we get to in-crop herbicide application or other methods for controlling them, they’ll be at a (larger) stage and it’ll be really challenging to do anything effective for weed control,” she said. “While it might be a time crunch, it’s still important to think about how you’re going to effectively manage those weeds, making sure that you’re doing whatever pre-seed tillage or whatever herbicide applications ahead of time to help get that crop off to the best start that it can have.

“I recognize that fertilizer is important,” she added, “but there is also a critical weed-free period that helps establish the yield potential of the crop and you sort of need to be able to make the concessions for maybe a day or two delay in seeding in order to make sure the weed control is done effectively.”

Exact plans will differ from field to field, depending on weather and field conditions, she noted.

The post Spring weeds rise up well ahead of seeding efforts appeared first on Manitoba Co-operator.

In a Manitoba demonstration this July, attendees noted that the WEEDit system missed some smaller weeds during a single pass. That could be addresses by adjusting sensor sensitivity or by turning on “dual mode,” which sprays a constant quarter-rate to take care of less hardy weeds on top of the green-on-brown trigger if the system hits a bigger weed, Saskatchewan spray expert Tom Wolf said. Both of those would cut into savings, he noted.

For green-on-green sensors, the road ahead is still longer. Xarvio’s Warren Bills noted that their team is still fighting with dust, vibration and speed issues. The dataset that their smart sprayer must run through to identify an issue, decide on a course of action and then carry that action out is huge, he noted, and making those decisions at speed is an issue. The technology has focused on the traits of younger weeds since that is when control is needed, he added.

“It will take more data, more care and attention and better refinement of some of these image recognition algorithms for us to get to that point of full confidence,” he told Glacier FarmMedia in July at Ag In Motion.

Regional weed variation poses another wrinkle, since growing conditions may impact a weed’s physical traits and a weed growing in the southern U.S. might look very different in the Canadian Prairies. In other cases, software developed elsewhere in the world might not be uploaded with data from local species.

Xarvio is relying on their global reach to deal with that problem. The software includes a huge pool of images for species drawn from across the globe, Bills noted. Developers of Xarvio’s app, which formed the basis for their smart sprayer, argued that identification would get better as more people used and fed data into the app.

Daniel McCann of Precision.ai, meanwhile, is taking a more local tack. His software is, in fact, developed in Western Canada, and hopes to better-tailor his datasets for the Prairies.

“We’ve actually sent people out into fields with cameras in Saskatchewan and Alberta and Manitoba to actually capture the weeds and crops that are growing right here,” he said.

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Tall Waterhemp is a Tier one noxious weed that must be destroyed no matter where it’s found, but that can include hand weeding within crops where practical, Jones said.

“One or two plants one year can be thousands of plants the next year…” she said. “It’s really aggressive. Its terrifying.”

The latest cases are in the R.M.s of Rhineland, where the weed was found in a different field two years ago, Reynolds and Whitemouth.

There was a previous case in the R.M. of Ste Anne.

Two cases of Tall Waterhemp were found in Manitoba in 2017. One plant was found last year.

Manitoba Agriculture will monitor the four fields and test the weeds to see what herbicides they are resistant to (click here for a distribution map of waterhemp in Manitoba).

Most Tall waterhemp in the United States is resistant to glyphosate.

Jones is urging farmers to report any weeds they suspect are Tall waterhemp. She worries some might be reluctant to do so, but if caught early the weed can be more easily controlled, she said.

“I think a lot of people may let it go when they have one or two suspect plants,” she said. “In a couple of years that becomes a huge patch and that’s what has happened in at least two of these cases. It was tiny to begin with.

“There are so many unknowns it’s hard to figure out a management plan, but Manitoba Agriculture can help with that. If we can catch it early we have a positive story, but if we let it go it’s such a negative story.”

Manitoba Agriculture has information on Tall Waterhemp on its website.

Here’s what it says:

‘Tall Waterhemp has been detected in at least three municipalities in Manitoba in 2019. Tall waterhemp is a significant weed of corn and soybean production in the Midwest United States and has been confirmed in several counties in Ontario. While plants have been sited in Manitoba in previous years (see map), the severity of the infestations this year is a significant cause for concern. Previous discoveries in Manitoba involved small patches or individual plants but this year’s detections involved a substantial number of acres, significant hours of rogueing, mowing and spraying to destroy plant material, and will require years of monitoring and surveillance to ensure the Tier 1 Noxious Weed has been eliminated.’

Identification

Tall Waterhemp has oval to lance or spearhead shaped leaves, 3-6 inches long, and:

• alternate leaf arrangement
• petiole is shorter than the length of the leaf blade
• hairless stem
• typically grows 4-5 ft. tall but can grow to more than 10 ft tall
• dioecious – meaning there are distinct male and female plants
• many small green flowers form an inflorescence in July-September
• the terminal inflorescence can be more than 1 ft long, with many wiry lateral branches

Tall waterhemp emerges throughout the growing season (April -August), typically after most other summer annual weeds have been sprayed.

It will flourish when there is sunshine, as is often the case in row crops. Season-long competition by waterhemp (more than 20 plants per square foot) has been shown to reduce soybean yield by 44 per cent.

Waterhemp that emerged as late as the V5 stage in soybeans can reduce yields up to 10 per cent.

Tall waterhemp is a prolific seed producer, generally producing about 250,000 seeds per plant, although individual plants can produce more than one million seeds under optimal conditions.

Like most weeds, waterhemp seeds remain viable in the soil for several years.

Tall waterhemp has documented herbicide resistance to many different classes of herbicides. In the U.S.

Tall waterhemp has evolved resistance to at least seven herbicide classes, including Group 2, 4, 5, 9, 14, 15 & 27.

Many populations exhibit multiple herbicide resistances that include several herbicide families. For example, Group 2 and 9 (e.g., ALS inhibitors and glyphosate, respectively) resistance in Tall Waterhemp is fairly common.

Tall waterhemp populations detected in Manitoba are suspected to be resistant to glyphosate, along with one or two other herbicide classes.

The post New cases of Tall waterhemp found in Manitoba appeared first on Manitoba Co-operator.

Provincial weed specialist Tammy Jones warns that producers might be in for a tough weed control season, despite cool temperatures and dry conditions keeping weeds from gaining ground early this year.

Why it matters: Clean fields this spring may have been a smokescreen for challenging weed control conditions now that the season is underway.

“The right weather this year might be a challenge for a number of reasons: dry conditions, the heat, now something that looks like a frost event for some,” Jones said. “It’s going to be a challenge, but we have to try and do the best that we can.”

Smaller is always better when it comes to staging weeds for control, most experts warn, but farmers noted a distinct lack of weeds this spring, leading some to question their pre-seed burn-off when added to lack of rain and tough growing conditions for the crop.

Farmers were unsure if they wanted to spend the money on a crop that may not germinate well, Jones said back in May, noting that those farmers may have forgone that risk in favour of in-crop control.

Farmers with poor stands and little competition with weeds may now be fighting the results of that decision.

“I’m not looking forward to trying to get guys through the challenges that I think they’ve set themselves up for by skipping that pre-seed burn,” she said after a May 29 weed seedling identification day in Brandon.

• Read more: Dry year adds to spray considerations

Jones was still seeing late-emerging green foxtail at the one-leaf stage at that time, she noted, while dandelion and stinkweed had not been controlled in some fields and had already matured into flowering and largely past the label for chemical control.

Delayed weeds complicated the decision of whether to do a burn-off, sprayer specialist Tom Wolf said. Wolf is one of the leads at Saskatchewan spray company Agrimetrix, as well as one of the main voices behind the blog sprayers101.com.

At the same time, he said, the decision to hold off on spray is “a perfectly sound decision” when few weeds are up.

“The weeds do have to be present and the question is, if there are only a few present, is it worth spraying? What’s the cost of letting those big weeds, or those present that will be big after seeding, survive? What are the yield implications or other implications of that?” he said.

Frost, wind and woes

Those who did want to spray may have had little luck.

A string of frost events chipped away at herbicide efficacy in late May and early June. Temperatures widely dropped below zero May 26-27, while the east Interlake and parts of central Manitoba woke up to yet more frost June 2. Parts of the northwest and Interlake saw yet another frost June 12, dipping to -1.3 C in Fisher Branch.

Frost events were spaced out just enough that weeds had started to recover and spraying could get underway again, when the next frost would hit, Wolf noted.

“You need to spray, everything else is relying on you to get that pre-seed burn-off done because the seeder’s moving and you can’t stay ahead of the seeder and that has a cascading effect,” he said.

Both Jones and Wolf noted added challenge from the lack of rain. Weeds may be drought hardened, Wolf noted, while Jones pointed out that the weeds may be adjusting to the dry conditions, such as folding up leaves, something that reduces herbicide contact as liquid rolls off.

“I would say that dry conditions are amongst the most challenging that agronomists and farmers ever have because, in the first place, the herbicide mode of action requires a vigorous crop to be present as well,” Wolf said. “In the drought that we’re currently experiencing, that’s not happening, so then a greater reliance is placed on the herbicide to work well to control those weeds. In the second place, the drought does make it more difficult to control those weeds because they’ve also responded to the dry conditions and protected themselves and become a little bit tougher.”

Farmers may need to respond with higher herbicide rates, he added.

Some farmers may hold off for rain, afraid of missing a second flush, he said.

“That, of course, makes the weeds bigger, the ones that are present,” he said. “It actually results in potential yield loss because early removal is a key component of good weed management. These things all kind of roll into one big weed control problem in drought years.”

Time for tank mixes?

Dwayne Durand, manager of Shur-Gro Farm Services in Brandon, says his clients are applying about the same amount of herbicide as in previous years, but are looking for cheaper options.

“The application rates are normal,” he said. “The selection of products might be more highly investigated to see if there’s an opportunity to lower cost. But they’re not cutting corners; they’re just looking at alternative products.”

Farmers have also shown less interest in manufacturer programming, he said.

He has also seen no dramatic increase in the demand for adjuvants, despite weather-driven impacts on herbicide efficacy, he said.

The post A messy year for weeds appeared first on Manitoba Co-operator.

Many could also be glyphosate tolerant, but it’s hard to know to what extent, she said in an interview April 24.

“I know that it is distributed fairly thoroughly across the province, but there aren’t a lot of people who test for it and so I think it’s under-reported quite significantly,” Jones said. “And some people don’t bother testing because they just assume that it is.”

But when a herbicide fails to kill a weed it’s not always because the weed is herbicide tolerant, she said. It could be a combination of factors, including the environment and the weed’s own natural defences.

“Kochia gets super hairy and lamb’s quarters develop lots of wax on the leaves,” Jones said, adding those features make it hard for a herbicide to stick to them. “Sometimes the environment and the dryness impact more on that weed so that it’s harder to kill…

“And if the plant is not as actively growing because it doesn’t have abundant moisture it’s not maybe picking up that herbicide as quickly either and that can affect how well our herbicides work.”

The environment can also affect pre-plant or pre-emergent herbicide efficacy, she said. Most require a certain amount of moisture to be activated.

“As much as you try, nothing is perfect,” Jones said. “You need a backup plan or another option when the first one doesn’t work. It’s tough with all the weed pressure and all of the resistance (to herbicides) to have that strategy mapped out all the time.”

Kochia, in addition to being in some cases resistant to Group 2 herbicides and glyphosate, is always germinating under the right conditions, she said.

“So a one-pass system — cultivation or herbicide — you’re never going to control the entire population because it just keeps germinating,” Jones said.

The reduced threat of overland flooding along the Red River this spring also reduces the risk of common waterhemp and Palmer amaranth spreading here from the United States. Both are ‘Tier 1’ weeds under Manitoba’s Noxious Weeds Act.

Farmers with Tier 1 weeds are legally required to destroy the plants and seed, “because they are a significant threat to our economy,” Jones said.

Jones isn’t aware of any Palmer amaranth in Manitoba yet.

“Hopefully it’s not something we’ll see any time soon,” she said.

Some common waterhemp has been found.

“There has been some pretty significant efforts to make sure those fields have been monitored and those weeds have been destroyed.”

Both weeds are in the same family as redroot pigweed, which is a prolific seed producer and competitive with many crops.

Palmer amaranth in the U.S. is resistant to several herbicide groups, including glyphosate.

“Common waterhemp grows 50 to 70 per cent faster than redroot pigweed,” Jones said. “Palmer amaranth is even more aggressive than common waterhemp as far as growth rate and seed production.”

The post Weeds develop defences appeared first on Manitoba Co-operator.

That’s because they’re a community problem that cross property boundaries, according to weed scientist Muthu Bagavathiannan, of Texas A&M.

Finding a real solution will involve recognizing the nature of weeds as a community problem, and managing them accordingly, he and other researchers wrote recently in the journal Nature Plants.

Bagavathiannan and fellow researcher Sonia Graham jointly led a 15-person team around the world that looked at weeds through a “cross-boundary lens.”

The paper, they say, is a call to action for scholars and practitioners to broaden their thinking and approaches to weed management problems, beginning with evaluating the “public-good” characteristics of specific weed management challenges.

“The public-goods lens highlights the broader social vision required for successful weed management,” Graham said. “Public goods like weed management are best achieved with the help of many people living and working across landscapes. We need to make the most of the diverse interests, knowledge and skill sets of those involved in managing weeds.”

Agricultural and natural landscapes worldwide are affected by weeds, but management techniques have primarily been developed for individual landowners. The practices rarely look at how control from a collective perspective would improve overall weed management outcomes.

“We suggest that a major limitation of current best management practices is an underappreciation for the complex, multi-scale and collective nature of the weed problem,” Bagavathiannan said.

The post It takes a village to stop weeds appeared first on Manitoba Co-operator.

That was the message to attendees at this year’s BASF Knowledge Harvest in Brandon Feb. 13.

As of 2015, there were 65 unique weed-resistance cases in Canada, AAFC’s Bob Blackshaw said, a number that rose from near negligible in 1975 and sat under 50 in 2005.

“It’s very difficult because we have resistance in insects and in diseases, but we’ve had some new modes of actions being introduced in recent years by various different companies, so that’s helped a lot,” Blackshaw said. “It sort of helps manage our existing resistance and it doesn’t stop us from future resistance, but it’s another tool for producers to use, but we just haven’t had a new mode of action, a truly new mode of action herbicide, for more than 25 years, so that’s why the resistance story is a little bit more critical than in some of our other pests in crop.”

Growing problem

Resistance has also been on the rise in the province. The 2016 Manitoba herbicide-resistance survey found that 102 of 151 fields surveyed, or 68 per cent, had herbicide-resistant weeds, up from 48 per cent in 2008.

Breaking down those results by weed, producers may be unsurprised to see Group 1-resistant wild oats pulling ahead of the pack, present in 78 per cent of surveyed fields.

Of greater concern, according to Blackshaw, is the number of wild oats now resistant to Group 1 and Group 2 herbicides, a class that now accounts for 42 per cent of surveyed fields, according to the 2016 study.

Wild oats are among the top weeds in the province, although their abundance slipped in 2016 relative to wild buckwheat and barnyard grass, according to the provincial weed survey.

Manitoba’s top weed, however, also makes the list of herbicide-resistance concerns. Green foxtail was found in 24.4 per cent of the 659 fields in the 2016 weed survey (and at an average density of 14.6 plants per square metre). Resistance numbers, meanwhile, showed Group 1 resistance in 44 per cent of the 50 fields it was found in during the resistance survey that same year. Fortunately, Group 2 resistance still remains low.

A similar story has emerged for yellow foxtail, a weed that had provincial specialists concerned with its debut on the province’s top 20 weed list for the first time in 2016. Thirty-two per cent of tested fields showed Group 1 resistance and 17 per cent were resistant to Group 2 in the 2016 resistance survey, although weeds resistant to both were still low.

Kochia

Glyphosate-resistant kochia is not the challenge it has become in other parts of North America, but Blackshaw warned farmers not to drop their guard. Western Manitoba is at risk of resistant kochia, he said, despite the fact that both confirmed resistant kochia cases have so far been closer to Winnipeg and the Red River Valley.

“I’m not aware of any glyphosate-resistant kochia in this region,” he said after his Brandon talk. “But what I’ve become very aware of in recent years is just how much kochia is present in the Brandon area, the Neepawa area, the Virden area. I grew up on a farm near Virden; we had no kochia on the farm 30 years ago. I was on the farm this past fall and we had an incredible amount of kochia on the farm associated with areas that were too wet to seed in the spring and there was salinity development because of the high water table and all the wet years we’ve had and kochia is tolerant to salinity and it tolerates some of those wet conditions.”

The weed is a high risk for developing glyphosate resistance, he warned.

What’s the solution?

Andrew Reid, BASF technical service specialist, wants producers to think long term in their herbicide plans.

“The big thing from our perspective is proper usage of our products, understanding the risks associated with resistance development and continuing to search for innovation as we go forward into the 2020s and beyond,” he said.

The specialist urged producers to use tank mixes, rotate groups and employ multiple modes of action. More importantly, he told the audience, multiple modes of action should have two active ingredients targeting the same problem.

The chemical side of weed control is not producing new modes of action like it once was, both because of increased cost and regulatory hoops, Reid said.

Both Reid and Blackshaw said there has not been a truly new mode of action for decades, and another is not expected for years to come, although Reid says there are some active ingredients waiting in the wings.

“We screen about 100,000 molecules per year looking for activity on weeds or fungi or insecticides, but the big thing is, even if we could find some activity, (that) doesn’t necessarily guarantee that it will ever make it to market because there’s a lot of very strict regulatory processes that we have to go through,” he said.

At the same time, the AAFC researcher added, tailoring a tank mix may come with its own challenges.

“I think cost is always foremost in producers’ minds, so that is a barrier, there’s no doubt about that,” Blackshaw said. “They have to sort of think, ‘OK, if I’m going to spend an extra $10 or $15 an acre, am I going to get value today or maybe there’s sort of value if you think in terms of multiple years.’ Then we talk about using multiple modes of action on herbicides, whether it’s a tank mix or different kinds, but it’s very hard to, on every weed species, (to make sure) that there are actually multiple modes.

“Even if you’re willing to spend the extra money, it’s hard to come up with another herbicide that will be the perfect tank mix partner, especially in some crops,” he added. “You might be able to do it in wheat, but the chances of doing it in your pea crop or your lentil crop or something else is virtually zero.”

Beyond chemistry

Those challenges have put a new focus on adding non-chemical strategies to the mix. Increased seeding rate may be an economical way to deal with weeds, particularly in crops like wheat, Blackshaw said. Mechanical weed control is, likewise, something that producers have explored and that the organic sector is constantly looking to improve, although Blackshaw remains leery of erosion risk and increased tillage. He did tag the practice, however, for headlands, slough areas and very weedy fields, and noted that shallow tillage might limit soil damage.

“Tillage is a complicated issue and it depends on what kind of tillage and the frequency of tillage and how deep it is and stuff,” he said.

Longer rotations, however, have become a consistent recommendation among experts, Blackshaw included. The researcher argued that two- and three-year rotations have shown yield boosts while cutting down resistance pressure. But while Blackshaw joins the voices urging producers to space out their crops, tight rotations are still among the most popular in the field.

The ideal mix of chemical and alternative strategies will vary from farm to farm, Reid said.

“The biggest viewpoint that we have in understanding and understanding what the problem is and, generally, where I see the best place to start is scouting and testing and understanding what issues or what problems they have to manage in their operation and from there, depending on what their situation is, we can start to look at different perspectives or different solutions that would work for them,” he said.

The BASF employee suggested that farmers flag potential problem areas to watch and submit samples if they suspect a resistance problem.

The post Manage herbicide resistance in the tank and out appeared first on Manitoba Co-operator.

Weed surveys show foxtail barley is on the increase, Manitoba Agriculture weed specialist Jeanette Gaultier said Sept. 20 on her last day in the position, during the Westman Crop Talk webinar.

“In the fall the plants are moving everything back towards the root so that they can overwinter and of course the glyphosate is going with it — it’s a very terrible pun — but you are getting to the root of the problem,” Gaultier said.

Because it was dry this summer a lot of foxtail barley won’t be moving as many nutrients now to its roots. However, plants with green leaves will absorb the herbicide.

The recommended rate to control foxtail barley with glyphosate is one to two litres per acre of Roundup equivalent, but Gaultier said she usually recommends two litres.

“I just find that foxtail barley can be so difficult (to control), why take a chance?” she said.

Foxtail barley can be controlled (90 per cent of plants killed) or suppressed (60 to 80 per cent of plants killed) in the spring, depending on plant maturity, Gaultier said.

New plants are easier to kill than established ones.

“In spring I never recommend anything lower than the two-litre equivalent (Roundup),” she said.

Early application is usually better when controlling weeds. However, Gaultier said research at the University of Saskatchewan shows spraying a little later in the spring can be more effective.

“The reason is foxtail barley has such skinny leaves when it’s very small…” she said.

There’s a sweet spot when the leaves are larger, but before the plant gets too mature.

There are some in-crop control options when growing broad-leaved crops, using non-selective Group 1 grassy weed killers. They include herbicides that contain quizalofop such as Assure II, which offers control and Contender or Yuma, which offer suppression, Gaultier said.

Poast Ultra, with the active ingredient sethoxydim, works too.

New research from the University of Alberta shows some pre-emergence products suppress foxtail barley. One is Focus — a combination of cafentrazone (Group 14) and pyroxasulfone (Group 15).

The university also found layering Focus with glyphosate, or a Group 1, can work, but only ahead of spring wheat, winter wheat, soybeans and corn.

“The other big thing is it requires activation by rain,” Gaultier said.

It might not have worked this year because it was dry, she said.

Foxtail barley is often a problem on saline land so reducing salinity is another way to control the weed, she said.

Foxtail barley grows best under the same conditions that favour crops. It often stands out when conditions are dry because there’s less crop competition.

“I definitely think it has taken advantage of that this year,” Gaultier said.

Tillage is the best way to control foxtail barley, she added.

“It doesn’t have to be deep,” she said. “Unlike a lot of perennials, foxtail barley does actually have a very shallow, fibrous root system.”

Burying foxtail barley seed three inches can reduce its seed bank in two to three years.

But tillage isn’t always an option, especially in minimum- and zero-till systems.

The same is true of pastures. Kerb, an older herbicide, is an option, but since it breaks down quickly in the soil it must be applied late in the fall, just before freeze-up, Gaultier said.

It also needs moisture to activate it, which usually comes with snowmelt and spring rains.

However, Kerb can injure some grasses, she added.

Regar brome, timothy, bluegrass, red fescue and crested wheatgrass have poor Kerb tolerance.

Wheatgrass, meadow foxtail, buffalograss, green needlegrass, tall fescue, smooth brome, creeping and red fescue have intermediate tolerance.

Tall wheatgrass, western wheatgrass, slender wheatgrass, red top, creeping foxtail, orchardgrass, altai wildrye, Russian wildrye, meadow fescue, alkali sacaton have high tolerance.

The post Fall is the best time for controlling foxtail barley appeared first on Manitoba Co-operator.

Now researchers, writing in the latest edition of the journal Weed Science, are beginning to reveal more about how the weed works.

Kochia typically begins to emerge in the U.S. in late February or early March, before other summer annual weed species. It then disperses its seeds broadly by tumbling across the landscape.

Since the timing of weed emergence and seed persistence in the soil can influence the selection of effective weed control practices, researchers conducted a two-year study to explore kochia emergence patterns and seed persistence. They harvested kochia seed from sites in five Midwest states, buried packets of seed and exhumed them at six-month intervals to evaluate viability.

Emergence densities varied widely across the plots and study years — from as few as four to almost 380,000 seedlings per square metre. Cumulative growing degree days needed for 10 per cent emergence also varied widely. In Kansas, 168 days were needed, but only 90 in Wyoming and Nebraska. Researchers found that more than 95 per cent of kochia seed failed to persist for more than two years.

The findings have important implications for weed control. The authors say pre-emergence weed control should be initiated in the fall or very early in the growing season, to address the first flush of seedling emergence and seed production.

Other management techniques may include cover crops and even waiting for kochia to emerge before seeding.

The post Keeping kochia in check appeared first on Manitoba Co-operator.

Spotted knapweed was first detected in southeastern Manitoba in 2009 but has more recently been found at sites across central and western sections of the province.

The highly competitive weed can quickly degrade native plant communities by reducing native plants required both by livestock and wildlife.

We need to control it now or face potential problems potentially even greater than those posed by spurge, warns the ISCM board, which declared August Invasive Species Month.

It’s highlighting this particular invasive weed because there’s still time to get on top of it, said Michelle Ammeter, with the Manitoba Weed Supervisors Association.

“By recognizing infestations early, and getting them under control, we have the potential of reducing the impact of spotted knapweed before it has the economic impact that leafy spurge does in Manitoba, or knapweeds do in other jurisdictions,” she said.

Big threat

Doug Cattani, a professor at the University of Manitoba and another ISCM board member said the highly invasive weed could potentially be even more problematic than leafy spurge.

A study released in 2010 showed what impact spurge had. That year it was determined it had spread over more than 1.2 million acres, affecting pastures, natural areas, hay and forage land, as well as roadsides, rail lines and utility corridors and having an economic impact of $40.2 million.

The main concern is that once it gets into native range it will quickly spread largely undetected, which is what happened with leafy spurge, Cattani said.

“Even with the activities and resources put into controlling leafy spurge I think between the 1999 and 2009 reports there was about a four times increase in area,” he said. “There were programs, but it was in areas that were hard to get at.”

Spotted knapweed has already caused significant damage to rangelands in both British Columbia and Alberta.

It’s on Manitoba’s Noxious Weeds Act and regulated under the federal Weed Seeds Order.

It was first detected in the southeastern corner of Manitoba in 2009 and before that thought to be an isolated incidence, say other ISCM board members. But new sites in recent years have been detected east of Winnipeg and north of the Trans-Canada Highway.

“Over the last couple of years we’ve been finding new sites east of Winnipeg and along Hwy. 1 towards Brandon and Deloraine and in the Sandilands area,” said Cory Lindgren, another ISCM member and Canadian Food Inspection Agency representative with the council. It’s also been found in a number of locations along Hwy. 12 near Steinbach.

It is believed that it has been spreading via rail lines and that plants are “hitchhiking on the rails” into Manitoba from northwestern Ontario, he said.

No competition

The problem with it is no animal will graze it and the biochemicals it produces alter surrounding soil, preventing growth of other plants around it and quickly allowing it to become a monoculture.

Spotted knapweed is identified by its distinctive bright-pink flowers and dark bracts on the flower which give it its spotted appearance.

In the first year of reproduction, the plant will bolt in mid- to late June and begin to flower in late June or early July. Flowering continues through August in most years. Seeds from one plant can produce well over 1,000 seeds which remain viable in the soil for five or more years.

The invader prefers dry or well-drained sites and can quickly invade ditches, roadsides, fields, rangelands, or gravel pits.

The ISCM board decided to declare an Invasive Species Month in August following suit with other programs across Canada now putting concerted effort into public education and awareness about the potential harm invasive species can cause, Cattani said.

Other invasive non-plant species have been attracting widespread attention, he noted.

“We’ve seen things like zebra mussels in the last few years really hit the forefront. It’s an invasive species. And I think we’re waiting with bated breath for the emerald ash borer to get into this jurisdiction,” he said.

“We’re trying to get on the side of ones that are just arriving or have imminent arrival and making the public aware so they can be the eyes in the landscape to let us know what’s happening,” he said.

Any sightings of spotted knapweed should be reported to a Manitoba Agriculture office and the Canadian Food Inspection Agency as they both have regulatory authority over weeds and invasive plants.

For more information on Invasive Species visit invasivespeciesmanitoba.com or email the group at invasivespeciescouncilmanitoba@gmail.com.

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