The results from that research, led by Olds College research scientist Shabeg Briar, have been promising.

Nematodes are tiny roundworms that live in the soil and infect insects. Several species have shown high levels of pest control in lab tests.

A proven but underused tool

While they’re often seen as a crop pest, interest in using nematodes to control insect pests isn’t new. In the 1980s, Cornell University researcher Elson Shields began testing beneficial nematodes as a long-term control for alfalfa snout beetle, work that would eventually help establish him as a pioneer in the field.

But alfalfa snout beetle was a very localized problem, confined to a handful of counties in New York and Ontario. That limited the commercial appeal for widespread agricultural use and, for the most part, nematodes have remained niche tools, used mostly in greenhouses and by home gardeners.

“They are currently not available in the Canadian Prairies for larger-scale use on field crops,” Manitoba Agriculture entomologist John Gavloski says. Production and marketing could scale up, he adds, if nematodes proved effective against major field crop pests.

Research done in Ontario looking at using beneficial nematodes to treat corn rootworm had promising results, he says. With continued positive results from these kinds of studies, the technology could soon become a familiar tool in Prairie farmers’ integrated pest management toolbox.

Encouraging results from Alberta

The Alberta study tested four types of commercially available entomopathogenic nematodes (EPNs) at various concentrations to see which were most effective.

The nematodes stacked up well. Diamondback moth larvae showed up to 90 per cent mortality; lygus bugs, up to 87 per cent; and black cutworms were almost entirely wiped out. Cabbage root maggots were also effectively controlled, reaching 83 per cent mortality, but the pupae proved more difficult to kill. Unfortunately for canola growers, their No. 1 pest, the flea beetle, appeared largely unaffected, with only 10 per cent mortality.

Still, the overall results are encouraging. With insecticide resistance on the rise and fewer chemical options available, biological tools such as EPNs could offer Prairie growers an environmentally friendly way to target insects hiding below the surface. While this would clearly be beneficial for organic growers, Gavloski suggested it would appeal to conventional farmers as well.

From lab to farm

While EPNs have yet to become available to farmers on the Canadian Prairies, the technology is already being put to use in the United States, thanks in part to the same researcher who helped pioneer it.

Elson Shields and his son Keegan have launched a company, Persistent BioControl, that’s beginning to open commercial markets for beneficial nematodes in the U.S., starting with corn and alfalfa farmers in the northeast.

The Iowa-based company grew out of Elson Shields’ decades of research, which demonstrated nematodes could provide long-term, soil-dwelling control of certain insect pests. But translating that academic success into a field-ready product wasn’t easy.

When he was thinking about retiring, Keegan Shields told his father if he didn’t want to see the technology sit on the shelf and go to waste, they ought to create a commercial source so farmers could buy it.

“The next step was to take it out of the lab and create a viable commercial enterprise,” Keegan Shields says.

Persistent BioControl was launched in 2019. When Elson retired from Cornell in 2022, he shifted his focus from research to business, taking on the role of chief technology officer for the company. Keegan is CEO.

Unlike most nematode products on the market, typically used as short-lived biopesticides in greenhouses or gardens, the nematodes sold by Persistent BioControl are designed to remain in the soil for a decade or longer after a single application. That has made the product especially appealing to row crop and forage producers.

“Our angle, and what makes this work for corn and other row crops, is the fact you can apply this one time and it’s going to give you the benefit for at least a few decades,” Shields says.

So far, more than 100,000 acres across the U.S. have been treated using this approach, most of them in New York. The company also works with organic vegetable growers targeting wireworm in root crops such as sweet potatoes, radishes and turnips, where nematodes are applied ahead of crop rotation to prevent feeding damage.

Application doesn’t require any specialty equipment. The nematodes are either injected into centre pivot irrigation systems or applied through conventional ground sprayers. For spray rigs, the tank and lines must be flushed, and all screens and filters removed.

Long-term value

The company uses a mix of three nematode species, adjusting the blend and application rate based on region, crop and pest pressure. For corn rootworm, the full cost is around US$70 per acre — higher than the $30 to $40 typically spent on soil insecticides. But for many farmers, the long-term value is clear.

“I thought I was going to have to spend a lot of time explaining the multi-year payback,” Shields says. “But they all get it immediately. You can see them start doing the math in their head: If I can eliminate my soil insecticide, this is a two-year payback, and if it works for the next decade, I’m a whole lot of money ahead.”

While Persistent BioControl hasn’t yet entered the Canadian market at scale, Shields says they’ve begun working with organic growers in Ontario, first by overnight shipping small orders and more recently by setting up a broker-assisted process that allows customers to legally bring product across the border themselves. Since the nematodes are naturally occurring and non-invasive, they don’t raise regulatory red flags.

Scaling up

“This will be year six for us,” Shields said. “We’ve got a lot of demand, and now we’ve got the ability to produce for 100,000 acres a year. We’re just going through the struggles of scaling up — hiring people, building out the facility, et cetera.”

Shields wasn’t familiar with Briar’s research in Alberta but says he’s keen to see nematodes explored in crops such as canola. “I would imagine any kind of treatment in canola is going to be similar to corn.”

The post Using nematodes to control crop pests appeared first on Grainews.

At a forage workshop hosted by the Canadian Forage and Grassland Association at the University of Manitoba in March, Manitoba Agriculture entomologist John Gavloski highlighted several key insect pests that can affect forage production and shared strategies for managing them.

Grasshoppers

Grasshoppers are a common pest in Prairie fields. Canada is home to 129 species of grasshoppers, but very few of those cause crop damage. There are only four or five grasshopper species that are considered to be pests, and of those, three are responsible for most of the damage.

“The top three grasshoppers in our survey this year are two-striped, which has been our dominant species in recent years, followed by either clear-winged or migratory,” Gavloski says.

All three have a similar life cycle. They all overwinter as eggs, laid in clusters of 20 to 30. The individual eggs resemble grains of brown rice.

“If you can dig those up easily, then you know you’ve got a decent grasshopper egg population,” Gavloski warns.

—> MORE ON FORAGES: Managing diseases in alfalfa

The ideal time for control is when the grasshoppers’ wing buds become visible. At this stage, the hatch is likely complete.

“Try to figure out what those newly hatched populations are like,” he says. “That will help you with your decision-making later on.”

Farmers can also lean on provincial grasshopper risk maps. Each of the Prairie provinces puts out a risk map in the fall based on samples taken, usually in August. The maps can help estimate the next season’s egg-laying potential.

While these maps can help, Gavloski warns they’re estimates and don’t guarantee outcomes for the following season. Weather conditions after the surveys have been done can affect populations. A warm fall with a late frost can mean there is more development within the egg, and the hatch could come sooner. And while the eggs are waterproof, heavy rains after the hatch, when the young grasshoppers are small, lack fat reserves and need to feed, can lower survival rates.

“They’re more vulnerable when they’re really tiny,” Gavloski says. “They get disease, they get bloated and they can drown.”

—> MORE ON GRASSHOPPERS: Reduced-area pest spraying can still hit moving targets

Economic thresholds: Estimating whether grasshopper numbers have reached the economic threshold can be challenging.

Gavloski estimates grasshopper populations by walking 50 metres along a field edge or ditch, selecting five random one-metre square areas and counting the grasshoppers that jump as he approaches. He then disturbs the plants to check for remaining insects.

These counts provide an estimate of the grasshopper population. The process doesn’t give very accurate results, but can probably let you know if you’re near the threshold.

“Usually, you can get a ballpark range,” Gavloski says. “If you think it was somewhere around 12 to 15, that is good. You don’t have to know that it was actually 13.”

For forage crops, the economic threshold for grasshopper control is generally considered to be eight to 12 grasshoppers per square metre.

Control methods: Gavloski recommends using what is called the Reduced Area and Agent Treatments (RAATS), which involve treating alternating swaths of land. This method works because grasshoppers move from untreated areas to treated areas. Research done in Wisconsin has shown RAATS can provide very good control while using half the insecticide.

—> MORE ON FORAGES: Grow forages, starve weeds

“The results of the research showed they were getting 94 per cent control when they sprayed the whole rangeland, but they were able to get 81 per cent control by only doing half of the rangeland,” Gavloski says.

Insecticides such as Coragen (chlorantraniliprole) are commonly used to control grasshoppers. Coragen is effective, with relatively low toxicity to pollinators. Generic insecticide versions have made treatments more affordable.

Cutworms

Cutworms are a diverse group of pests in Canada. Gavloski spoke about three different categories of cutworms: climbing, surface-feeding and subterranean.

Climbing cutworms climb plants at night to feed, then retreat underground or under debris during the day. Unlike other cutworms, they don’t cut plants but leave feeding damage on leaves, which can be misleading when scouting. The dingy cutworm is the most common climber in Manitoba. It can be identified by small leaf-like markings on its body. To find them, dig around damaged plants.

Surface-feeding cutworms crawl along the ground and cut plant stems, leaving severed plants behind. If you see cut plants, dig around to find the caterpillars nearby. The redbacked cutworm is a common surface-feeding species. It is recognizable by two red lines running down its back.

Subterranean cutworms live and feed underground, making them difficult to detect and control. The glassy cutworm is an example of a subterranean feeder. It prefers grasses over broadleaf crops and is commonly found in forage and cereal crops.

Gavloski also pointed out that some infestations can appear in patches. The patchiness can depend on egg-laying patterns the previous season, but it can also depend on topography. In more rolling landscapes, the warmer, southern side of the slopes tends to attract the bugs.

Economic thresholds: Gavloski didn’t speak to economic thresholds in his presentation. Manitoba Agriculture’s website says economic thresholds haven’t been well researched for cutworms, but included some anecdotal thresholds for various crops.

For alfalfa (the only forage crop listed), the website suggests four to five larvae per square foot (30 cm) as a threshold. Otherwise, farmers can just make a judgement based on the level of plant injury. Visible, widespread damage that threatens plant stands would obviously signal the need for control.

Control methods: Management strategies depend on the species. Coragen Max is the only insecticide registered for cutworms in forages — and while Gavloski says more options are needed, the pesticide is effective.

“It is a very good product for cutworms, at least the ones that surface feed; it’s got residual, and it is basically harmless to bees and many beneficial insects.”

Since cutworms are most active at night, insecticides should be applied late in the afternoon or evening.

Unfortunately, the effectiveness of insecticides to control subterranean species is “hit-and-miss,” Gavloski says. “Because they’re not coming above the ground to feed, they can be a real nuisance to manage with insecticides.”

Targeted spraying of affected areas can be used in situations where an infestation is not widespread.

“If the problem is small — say, 10 or 20 acres have a lot and the rest of the fields aren’t bad — you can patch-spray for cutworms.”

Cereal armyworm

The pest Gavloski refers to here shouldn’t be confused with the better-known bertha armyworm, which is mostly a concern for canola growers. As the name suggests, cereal armyworms are more likely to be found in forage grasses than alfalfa stands. It is also known as true armyworm or simply as “armyworm.”

Adults don’t overwinter in Canada but migrate from southern areas, often carried by wind currents in spring and summer, and while they have a particular affinity for timothy, most forage grasses are excellent hosts for armyworms.

“When the adults arrive, they’re looking for a lush, dense grassy stand to lay their eggs into,” Gavloski says. “So a perennial grass is just ideal … that’s where the eggs often end up.”

However, if they defoliate enough in an area, they will start moving into other areas (these movements are why they’re called armyworms), and, while their preference is to feed on grasses, they may feed on broadleaf plants in lieu of a grass crop if that’s what’s available.

Armyworm larvae have distinct stripes, with a V-shaped marking on their heads. The colours can vary, but those striped patterns are usually visible. The adult moths are light brown with white dots on their wings. Armyworm larvae feed primarily on grasses and are often found in forage stands, especially in early spring.

When scouting for armyworm larvae, check multiple areas of the field, as populations can vary within a single field. Shake plants and inspect the soil for larvae, paying close attention to plant debris, soil clumps and cracks.

“During the day, they’re trying to hide, so they’re underneath the debris and may go into the cracks in the soil,” Gavloski says. “So you have to look in the cracks, peel away the debris and do your counts.”

In cereal and grass crops, begin scouting in late June and examine at least five areas, focusing on patches of lodged plants and grassy weed infestations. Fields or sections with significant bird activity should also be monitored, as birds often feed on armyworms. Additionally, check the backs of larvae for parasite eggs, which can indicate natural control.

Economic thresholds: The threshold for control varies by crop. For forage grasses, it’s generally five larvae per square foot (929 cm²). However, as mentioned, they love timothy. Instead of feeding on the leaves before moving on to the heads like they do with other grasses, with timothy, they attack the heads first. As a result, they may require intervention even if the threshold isn’t met.

“Sometimes, it will pay to control them at levels below a threshold, depending on where they’re feeding and how much damage they’re doing,” Gavloski says.

Control methods: Insecticide applications should be timed for the evening or late afternoon, as armyworms primarily feed at night.

As with cutworms, chlorantraniliprole is the only active ingredient registered for armyworms. The products Coragen Max, Coragen (the pre-Max version) and a new generic version called Shenzi are available for farmers to use.

Alfalfa weevil

As the name suggests, the alfalfa weevil is a major economic pest for alfalfa crops, but will also feed on other legumes such as clover, making it a major concern for many farmers growing forages.

Adults overwinter under plant debris and soil in and around alfalfa fields and emerge in spring, feeding on alfalfa leaves. Round, elongated holes in the leaves are an indication of adult alfalfa weevils feeding.

When females are ready to lay eggs, they chew a hole in the stem and deposit from one to 40 eggs. When they hatch, the larvae will feed upon the stem before moving to fresh buds and leaves. After the larval stage, they make silky cocoons that, if the infestation is widespread, can be visible as a white haze over the field.

“People often first notice this driving by their field and see the crop is looking kind of frosted,” Gavloski says. “If you see this, you’ve probably got lots of feeding, and you probably should have been in there earlier.”

As a general guideline, he recommends scouting for the bugs in early June and continuing weekly checks.

“They should be hatching out by then,” Gavloski says. “You should be on top of things before it gets too bad.”

Economic thresholds: Alfalfa weevils cause significant damage, particularly to young alfalfa crops. The general action threshold for larvae varies based on crop height. For hay crops under 30 cm, the threshold is one larva per stem. For crops between 30 and 40 cm, it’s two larvae per stem. If three larvae per stem are found, control measures are generally needed.

Control methods: For hay crops, cutting the plants early is the main strategy used to control the insects because the larvae will starve or desiccate after cutting. Several insecticides are available for use, but many only provide partial suppression.

“Our insecticides don’t always work well for alfalfa weevil,” Gavloski says.

Natural predators, such as parasitoid wasps (bathyplectes and oomyzus), can help control alfalfa weevil populations. These predators can sometimes reduce the need for chemical control.

Lygus bugs

Gavloski also touched on lygus bugs. They are primarily a concern for alfalfa seed producers rather than forage growers. Lygus bugs are sap-feeding insects that use their beaks, like mosquitoes, to inject enzymes into plant tissues and suck up the sap. They target nitrogen-rich growth, damaging buds, seeds and flowers.

While there are suggested economic thresholds for control of the bugs in seed alfalfa, and insecticides are available, control is not recommended for alfalfa grown for hay.

The post What insect pests are bugging your forage crops? appeared first on Grainews.

A long-lasting lure attracts the rodent to the trap. When it sticks its head into the trap a piston strikes it on the head, killing it instantly. A spring retracts the piston, readying it for the next strike. The rodent is then left to be carried off by a natural predator such as a fox or raccoon.

The lure remains fresh for up to one month.

Traps retail for $99.99. A more sophisticated option is the Smart Trap Kit, which relays trap data to a smartphone app, which includes number of kills, date, time and environmental conditions. That system retails for $199.99.

More information is available on the company’s website.

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Saskatchewan’s Ministry of Agriculture recently conducted a survey of farmers to better understand where Richardson’s ground squirrels are present, the methods producers use to deal with them, and which approaches are most effective.

The online survey was conducted this past December and January. A total of 174 farmers responded. They were asked questions about:

• type of acres on their farm (cropland, range, pasture, yards) affected by ground squirrels;
• number of acres affected;
• severity of damage; and
• type and effectiveness of control techniques.

James Tansey, pest management specialist with Saskatchewan Agriculture, says the province plans to conduct the survey annually to gather more accurate data.

“We’re hoping for a number of things. First and foremost is to engage with growers and gauge their satisfaction with different products, gauge that over a number of years and get some feedback from them about how we can attenuate control programs and attenuate our extension message.

“I think the ultimate goal is to get some year-to-year weather data where we can get some predictive power and can say, OK, the winter and spring have been this and in the past, this has contributed to gopher populations in these regions … and these regions should be looking at (the problem) a little bit more.”

Richardson’s ground squirrels, often referred to as gophers, can be a major problem for farmers and ranchers when present in high numbers. They can devastate crops such as cereals, hay and alfalfa and pockmark pastureland.

They are a provincially regulated agricultural pest.

“This survey seemed to be, after some discussion, the best bang for our buck. It provides the greatest engagement of growers and good information,” Tansey says.

Respondents indicated damage to cropland, pasture, range and yards. About half indicated high or medium satisfaction with the performance of poison baits. That number increased to about 78 per cent in controlled yard settings.

Shooting also ranked fairly high in terms of satisfaction as a control method.

The survey didn’t provide data on drowning, trapping or vegetation height as control methods since they aren’t practical in crop settings.

However, in smaller settings like yards, keeping vegetation height above 15 centimetres was more commonly used, though satisfaction with this method was relatively low.

Underutilized tool

The survey also showed most farmers aren’t likely to use raptor platforms as a tool to control gopher populations. Such platforms provide nesting sites for predatory birds that feed on gophers.

Tansey says that indicates the need for better communication, because raptors “can inflict some pretty significant damage on ground squirrel populations” and farmers can apply for rebates for the purchase of raptor platforms as well as bird boxes for smaller predatory birds.

Attracting raptors and other predators can also induce more stress on ground squirrels, so they move underground and have less time to damage crops.

“We would certainly like to see an uptake in that and just more of a tolerance of predators like badgers. We know they can cause a lot of damage with their burrows. But if you can tolerate that, they can be an important factor in reducing ground squirrel populations,” says Tansey.

The initial survey didn’t show the correlation between weather patterns and their impact on ground squirrel populations.

Conditions were relatively uniform in areas where ground squirrels were reported, in terms of temperature, precipitation and drought index.

“I was hoping for a little more smoking-gun evidence from a weather perspective, but this is only one year’s data. I think if we get multiple years (of) data on this, then we should get some predictive power.”

Tansey says he was pleased that responses came from throughout the province, from northern growing regions to all three borders in the south.

He was also happy with the number of responses from farmers who didn’t report a problem with ground squirrels, because that provides more objective data.

Alternatives

This spring will be the first time in several years that liquid strychnine will not be available for use in grain-based poisons to kill ground squirrels. Deregistration by the Pest Management Regulatory Agency went into effect March 4, 2023, after a three-year phase-out period.

Saskatchewan Agriculture, in collaboration with Alberta Agriculture, conducted a series of trials in 2022 and 2023 to assess the effectiveness and non-target safety of alternative products. Tansey says some of the most promising are zinc phosphide ready-to-use baits such as Burrow Oat Bait and ZP Rodent Oat Bait AG.

“We found that the two zinc phosphide products we tested work well and were statistically similar in their effect as strychnine and we’ve seen a real uptake of it. It’s actually a little bit less expensive than strychnine,” he says.

Zinc phosphide breaks down into phosphine gas after a gopher dies, which means there is less residue than with some other poisons.

Tansey says several anti-coagulant products also appear to be effective. He cautions that users should understand that multiple applications are required, which can boost product and labour costs.

Aluminum phosphide is another option, but it can be dangerous to handle and requires training. Tansey suggests those interested in using it should hire a professional applicator.

Forecast

Persistent drought conditions in parts of the Prairies are thought to be one of the primary reasons for high ground squirrel populations in recent years.

Tansey says evidence indicates that cool, wet conditions can contribute to bacterial and fungal infections in animals. That can lead to depressed populations in some species, including ground squirrels.

Future surveys may confirm that and provide more evidence on the impact of weather on populations.

The results of this year’s survey were made available in late April on the provincial government’s Richardson’s ground squirrel control page.

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Persistent drought conditions have contributed to high ground squirrel populations in some parts of the Prairies in recent years.

“I would say the last four years were horrible,” says Christine Hoffman, chief administrative officer for the Rural Municipality of Maple Creek in Saskatchewan.

“They will eat just about everything in their path. I know gophers enjoy all seed when farmers are seeding in the spring, but they really hit corn hard as they seem to really enjoy that. They will actually dig out each seed kernel,” she adds.

“If there is anything left to grow, it is very patchy and that, in turn, causes weed issues and, obviously, poor crop production.”

Shawn Kramer, who operates a cattle ranch and is also a deputy reeve in Maple Creek, maintains ground squirrels can cause a lot of issues for ranchers and farmers alike.

“They make a mess and because of all of the holes, you’ve got cattle coming up lame. They can also wreck hay land. On some of our hay land, they ate the alfalfa down to where it’s gone completely,” says Kramer.

“If you’ve got a nice crop, something like four-feet-high wheat, you can’t really get out into the middle of a big field to control them. You’ll be combining or swathing and then you come to a spot where there’s just nothing because the gophers have eaten it down completely,” he adds.

“In our area, this is getting to be about six years of drought now, so the crops or the hay haven’t been great to begin with. A few acres may not seem like a lot, but when you’re not getting much on production anyway and then you’re losing it to gopher damage, it’s a tough battle.”

James Tansey, the provincial insect and vertebrate pest management specialist with Saskatchewan Agriculture, says ground squirrels can damage canola, cereals and hay as well as pasture.

“They’ll go into the crop and raid it, directly consuming the plant material,” he says. “Their burrowing also can be very extensive, especially if populations are large, and that can have a negative impact on equipment as well as livestock.”

Tansey says there are a couple of reasons why ground squirrel numbers are up in Saskatchewan. One is an abundance of green stuff for them to feed on when they started emerging from their burrows after winter.

Tansey says insects must also affect ground squirrel populations. Grasshoppers are an important food source and there were lots of them around in 2022 and this year as well.

“We had a bit of a cool, wet start to things this spring. I think what that did was really bring up the growth of green feed for the animals,” Tansey says. “The (plants) came up looking pretty healthy and the (ground squirrels) had a lot to eat.”

Poison bait

Tansey notes producers frequently use poison bait to control ground squirrels early in the season, but when there is a large amount of green vegetation around, it can make them less effective.

“If the poison baits are put down while there is green feed and the animals have something to choose from, there’s a pretty good chance that they’re not going to go for the baits. They are going to go for the green feed instead. They develop a bit of bait shyness if they have choices,” Tansey says.

“You will get some efficacy with continued use of poison during summer, but don’t expect complete knockdown or expect great efficacy,” he adds. “Our recommendation is always to put down poison bait in holes or in bait stations before the green-up. But, of course, the green-up came pretty fast this year.”

Tansey says mid-March to the end of April, before crop emergence and when there are fewer green plants, is generally the best time to place ground squirrel bait.

Kramer maintains tempting ground squirrels with poison bait traps just after the snow disappears from fields is ideal because that’s when they’re the hungriest. Missing that window of opportunity with bait traps could create problems down the road.

“Once you’ve kind of lost control in the spring and the gophers are everywhere, it makes it pretty hard to get them under control,” says Kramer.

For many years, liquid strychnine has been the primary poison used in grain-based traps for killing ground squirrels in Western Canada. A strychnine ban by the Pest Management Regulatory Agency (PMRA) that went into effect April 1 means that’s no longer an option for Prairie farmers and ranchers.

“We used to use strychnine when it was available and that worked the best,” says Kramer. “Once we lost strychnine, it made it a lot more difficult for us.”

Tansey says many farmers and ranchers were heavily reliant on strychnine, with some rural municipalities in Saskatchewan distributing it to growers as part of an integrated pest management (IPM) program offered by the Saskatchewan Association of Rural Municipalities (SARM).

The Saskatchewan Agriculture Ministry, in collaboration with SARM, has developed a new ground squirrel control program. SARM is administering the program. Details are available on its website.

There are other options for controlling ground squirrel populations apart from strychnine — everything from chemical alternatives to building perches for raptors’ nests near farm fields.

Rodenticide options

Other rodenticides for killing ground squirrels include zinc phosphide products, which are relatively low risk to non-target animals and birds.

“I know people who were trying the zinc phosphide bait early in the season. I heard of some successes, but it’s relatively new. We haven’t had a lot of feedback,” says Hoffman.

Anticoagulants such as chlorophacinone and diphacinone, which cause ground squirrels to die from internal bleeding after bait is eaten, are also used in poison baits.

Research has shown that anticoagulants are not effective if the surrounding crop stand is more than 40 per cent alfalfa, except when there is little green growth visible. That’s because legumes like alfalfa contain higher levels of vitamin K, which is the antidote to chlorophacinone.

Aluminum phosphide used as a fumigant in ground squirrel holes is another chemical option for control. It can be hazardous and is a restricted product requiring a pesticide applicator’s licence to purchase and apply as well as a documented treatment plan prior to use.

“There are several products available with the active ingredient aluminum phosphide,” says Tansey.

“Where that becomes a little more problematic is the documentation that’s associated with its application and some of the restrictions and training associated with its use, whereas the ready-to-use products containing zinc phosphide are very much just open a bag and either use it at a bait station or pour it down the hole.

“Aluminum phosphide also reacts strongly with water, including atmospheric water, where zinc phosphide needs a weak acidic solution, like a gopher’s gut, to break down and become very toxic,” he adds.

RoCon is a poison-free rodenticide developed by a pair of Alberta ranchers in the 1990s. The product is injected as a biodegradable foam in ground squirrel burrows and works by suffocating the rodents. Unlike baits, RoCon is not dependent on the feeding habits of ground squirrels and is effective as long as they are active in their burrows, according to the manufacturer.

A list of available products registered for ground squirrel control can be found on SARM’s website.

Strychnine alternatives

Following the PMRA’s decision to deregister strychnine, the agriculture ministries in Saskatchewan and Alberta started developing data on alternative products to control ground squirrels.

Two sister studies in the RM of Maple Creek and the Municipal District of Willow Creek, Alta., were conducted in 2022 and 2023 to compare the efficacy and economics of strychnine with these four products:

• Burrow Oat Bait (zinc phosphide)
• ZP Rodent Oat Bait AG (zinc phosphide)
• Rozol RTU Field Rodent Bait (chlorophacinone)
• Ramik Green Rodent Control Bait (diphacinone)

As a result of the study, Tansey says, the Saskatchewan and Alberta governments are recommending Burrow Oat Bait as an alternative to strychnine for controlling Richardson’s ground squirrels in the Prairies because of its efficacy and cost.

The study found no statistical difference in efficacy between Burrow Oat Bait and strychnine in 2022 and 2023. ZP Rodent Oat Bait AG performed well in the Saskatchewan sites in 2022, but results were more variable with this product in both the Alberta and Saskatchewan sites in 2023.

At $4.54 per acre, Burrow Oat Bait cost less than strychnine ($13 per acre) in 2022. ZP Rodent Oat Bait AG came in at $8.80 per acre in 2022. Tansey says the 2023 economic analysis is still pending but he notes prices have gone up for most rodenticide products.

The two anticoagulants in the study were found to be less effective than strychnine. Because of the initial purchase price and the need for multiple applications, the cost came in at $30 per acre for both products (two applications of Rozol and three applications of Ramik Green) at 2022 prices, more than twice the cost per acre of strychnine.

Non-chemical controls

Trapping and shooting have been used to control ground squirrel populations in the Prairies, with varying success. Because of the labour and costs involved, these options may be best suited for smaller areas with high ground squirrel populations.

“I have a couple of friends who come out on the weekends and shoot gophers for us,” says Kramer. “This seems to be the best thing we can do.”

Tansey says shooting is more common than trapping as a control method in Saskatchewan, but results are mixed.

“We’ve heard reports of ammunition shortages and of growers frustrated with not getting the control that they would like,” he says.

“Of course, if you do reduce a local population, you’ve left an unattended burrow system, and it’s entirely possible for another group of gophers to come in there and take advantage of that.”

Tansey says there’s continued focus on developing a long-term, sustainable management system, utilizing IPM practices that include rodenticides and non-chemical measures to keep gopher infestations below economic threshold levels (the point where pest damage exceeds the cost of the management options).

“I think to rely on any one specific IPM component is not going to get the efficacy that you’re hoping for. With integrated pest management, we’re looking for the incorporation of biological, cultural and chemical controls. All of these tools combined can help control Richardson’s ground squirrels.”

Cultural controls include habitat modification, which can reduce ground squirrel preference for an area and enable foxes, badgers, weasels and coyotes to have better success finding them.

Studies have shown that grazing practices that favour taller grass stands may reduce ground squirrel numbers because they prefer short grasses for better visibility for predator threats.

To reduce ground squirrel pressure, one technique is to maintain vegetation on pastures or forage at a height greater than 15 centimetres. Another strategy is to leave vegetation tall and ungrazed in headland areas and along fencelines so it can act as habitat for ground squirrel predators.

Tolerance is key

Ground squirrel predation can also be encouraged by erecting platforms and nest boxes for raptors near ground squirrel colonies. This is particularly useful in areas with few trees where suitable nesting sites may be in short supply.

“There are several species of raptorial bird that prey heavily on Richardson’s ground squirrels,” says Tansey, “most notably ferruginous hawks, which rely on them almost entirely for their fledglings.”

Tansey stresses tolerance for ground squirrel predators can be key to keeping the rodent numbers under control.

“Coyotes, foxes, weasels and badgers can do a lot of damage to a gopher population — in particular, badgers. I realize that badgers can do a lot of damage in fields and their burrows can be quite large, but they can have a profound effect on ground squirrel populations,” he says.

Tansey notes monitoring ground squirrel populations, and managing them when necessary, can help prevent crop and land damage and the associated economic losses when numbers get too high.

“I should temper that, though, with the need for some tolerance of Richardson’s ground squirrels. We don’t have any hope of ever eradicating them, nor do we want to,” he says.

“They are important components of grassland ecosystem functioning, and we need a certain level of tolerance for that. Unless a population is damaging, I think growers can step back a little bit.”

“I certainly appreciate some of the anxiety that growers are feeling, especially given the warm, dry conditions and the way this seems to be favouring gopher populations. I just think continued vigilance and the application of efficacious products where warranted is the best strategy.”

The post Prairie pest offers ‘a tough battle’ appeared first on Grainews.

During a June 14 webinar offering advice on managing grasshopper populations, James Tansey of Saskatchewan Agriculture said, “we’ve got a bit of a perfect storm for grasshoppers this year.”

According to Tansey, warm and dry conditions in the province last summer resulted in a rapid onset of adult grasshoppers, which laid a lot of eggs. Then, warm conditions and timely rains this spring produced a lot of green feed for young grasshopper nymphs to feed on when they emerged from the ground.

Tansey said one of the first steps for control is to identify what type of grasshopper is present. While 85 species of grasshopper have been identified in Western Canada, most are non-pest species and only four are what Tansey called “problematic” for most farmers.

Typically, non-pest grasshoppers have wings before late June with brightly coloured hind wings and are noisy flyers.

“A good mantra is, ‘if it has wings in the spring, it’s not a pest,’ ” Tansey said.

The most common pest-type grasshoppers in Saskatchewan are migratory (Melanoplus sanguinipes), Packard’s (Melanoplus packardii) and two-striped (Melanoplus bivittatus).

Migratory grasshoppers are a dark grayish brown tinged with red, with a yellowish belly and black bands on their hind legs. Host plants include forbs, grasses, wheat and barley.

Packard’s grasshoppers are gray to dark yellow, have two light-coloured stripes behind their eyes and blue tibias on their hind legs. They feed on vegetables and small grains but prefer legumes.

Two-striped grasshoppers have two pale stripes extending from their eyes to the tip of their forewings and a black stripe on their hind femur. They will feed on alfalfa as well as other crops such as cereals.

Monitoring methods

Tansey said there are two recommended methods for monitoring grasshopper populations in a field and determining numbers in relation to economic thresholds.

The first is the transect method in which an individual walks a 10-metre transect or path and uses a one-metre stick to estimate the number of insects in that area. The process should be repeated five times with the total number of insects divided by 50.

The second recommended method is sweep sampling in which an individual uses a net and takes four, 180-degree sweeps at different spots, repeated in at least five locations. It’s important not to collect any soil in the net.

While the sweep sampling technique takes time to perfect, Tansey said, it allows the person doing the sweep to hit multiple populations much quicker than doing a walking survey.

So, what if you discover pest-type grasshoppers in the field?

Tansey advises people to consult the 2023 Guide to Crop Protection for current information on products registered and marketed for specific crops. He warned against going off-label when using insecticides to control grasshoppers.

“Do not go off-label. I’ve heard reports about some off-label applications, and you can really get yourself into trouble with that,” Tansey said.

“If it has grasshopper on the label, you can pretty much take that to the bank that it’s going to be efficacious if you follow the label directions. If it’s registered, there’s a good reason for it. If it’s not, there’s also a good reason for it.”

Tansey also recommended that growers consider maximum residue limits of any products and follow recommendations on product labels.

Insecticide options

Tansey said Group 3 insecticides (synthetic pyrethroids) are effective against young grasshoppers. He noted examples for wheat include:

• Decis 100 EC and several other deltamethrin products
• UP-Cyde and Ship (cypermethrin)
• Silencer, LaBamba and Zivata (lambda-cyhalothrin)

Tansey said one exception in Group 3s is Permethrin insecticide, which has low efficacy against two-striped grasshoppers. He also cautioned against using lambda-cyhalothrin products on crops intended for animal feed, as some buyers may not accept it. The efficacy of most Group 3s decreases with very warm temperatures.

Group 28 insecticides, also known as diamides, are generally effective against adult grasshoppers, Tansey said. That includes products such as Coragen and Coragen Max. However, it may take several days for the insects to die after spraying.

“What freaks some people out a little bit about the Group 28s is they’re not knock-down insecticides like some of the other ones,” said Tansey. “The animal is still going to be alive, but it’s not feeding or it’s feeding much less.”

Tansey noted Group 1B products, known as organophosphates, are also effective against adult grasshoppers. These are some of the oldest chemistries available, some dating back to the 1930s.

He said some of the more popular Group 1Bs include malathion products, whose efficacy improves with warmer temperatures, and Lagon 480 E, which provides about eight days of residual efficacy.

Growers should be aware that Group 1B products containing chlorpyrifos, such as Lorsban, can only be applied until the end of this season, as they will be deregistered and unavailable for use in Canada as of Dec. 10.

Alternative solutions

Biopesticide baits, which are ingested by grasshoppers, are an alternative to insecticides. Tansey said Nolo Bait, containing naturally occuring Nosema locustae spores, is one of the more popular ones. It should be applied to fields when there is no above-ground harvestable food present.

Eco Bran, a wheat bran infused with carbaryl insecticide, is another effective bait that can “kill a large number of grasshoppers in relatively short order,” said Tansey. It cannot be used in crops such as corn, alfalfa, clover, wheat, oats, barley, rye and sweet lupins.

There are cultural control methods to protect against grasshoppers. Although they generally won’t provide knock-down or total mitigation of grasshopper damage, Tansey said, they can significantly reduce damage.

Cultural control options include:

• Early seeding produces more resilient crops capable of withstanding more grasshopper damage.
• Add crops that include non-preferred hosts, such as oats and peas, to the rotation.
• Tillage removes early green plants when grasshoppers are still in the nymph stage, effectively starving the insects.
• Trap strips lure grasshoppers to areas away from harvestable crops.

Tansey cautioned that growers shouldn’t become complacent even if conditions appear less than ideal for future grasshopper development this summer.

“Everything for next year depends on the conditions in July,” he said. “There are some factors that could contribute to their mortality … (like) if we get the onset of very cool, wet conditions.”

Tansey added if warm, dry conditions continue in Saskatchewan through the summer and grasshopper numbers remain high, “we could be looking at more trouble for next year, barring a very cool, wet spring and early summer next year.”

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Those products and others based on the lambda-cy active ingredient aren’t banned, but Health Canada’s Pest Management Regulatory Agency (PMRA) has ruled as of April 29 this year, any crops treated with lambda-cy insecticides cannot be used for livestock feed.

That “feed” reference, in one way or another, covers just about every grain, oilseed and pulse crop grown in Western Canada.

It is a confusing and oddball regulatory requirement most say isn’t based on science, is totally unworkable and will be difficult to enforce.

Furthermore, it could have far-reaching implications for both the crop and livestock sectors including international trade in feed products.

Producer commissions and commodity organizations from across the country have mounted a united appeal asking Health Canada and the PMRA to reverse or at least pause the implementation of the changed regulation. The effectiveness of that appeal is yet to be known.

In the meantime, as of late last year, Syngenta Canada and Adama, makers of Matador and Silencer insecticides, respectively, have pulled the products at least temporarily from the marketplace for the 2023 growing season.

While lambda-cy products are not available for 2023, several other insecticides with different active ingredients can be used for most common crop pests.

For a comprehensive list of alternatives for all major crops for 2023, visit this Saskatchewan Pulse Growers fact sheet, a joint effort produced with the support of SaskBarley, SaskCanola and SaskWheat.

While there are alternative products that can be used for insect control, industry observers raise this question: with a sudden shift in demand, will there be sufficient supply of these products?

Also, some farmers have pointed out lambda-cy products are not only effective on a wide range of pests, but they are cost effective as well. How do the alternatives stack up on the cost front?

The background

As a matter of course, agricultural chemicals are routinely reviewed or re-evaluated to ensure the registration data is still relevant and products aren’t posing a risk to human health or the environment.

The PMRA undertook a re-evaluation of lambda-cy products with a review completed in 2017. Similarly, the U.S. Environmental Protection Agency (EPA) also carried out a re-evaluation of lambda-cyhalothrin products registered in the United States.

The 2017 review led the PMRA to conclude lambda-cy products used on food crops posed no risk to human health or the environment, but “uses of lambda-cyhalothrin are cancelled since health risks were not shown acceptable when used according to the current conditions of registration” for several crops including “all feed uses.”

So, what’s wrong with the lambda-cy active ingredient prompting livestock feed use to be taken off of the label? What harm was it causing?

That’s the puzzling part — no one seems to know.

There has been no clear statement and, apparently, no scientific evidence that shows lambda-cyhalothrin was found to cause any environmental or animal health problems.

Although efforts were made to reach PMRA for comments, as of publication time no response had been received and no updates about the review ruling had been posted on the agency’s website.

Corey Loessin, a Saskatchewan farmer and a director at Saskatchewan Pulse Growers says, “To me, it is just a straight up error on the part of PMRA to designate feed as an off-label use with these products.”

Roger Chevraux, an Alberta farmer and Alberta Canola Producers Commission chair, says it appears the PMRA relied on some older data and technology to re-evaluate the chemistry, and, somehow, came to the conclusion there was a concern about the chemical being used on crops that produce livestock feed.

There wasn’t any scientific data, says Chevraux, but computer modelling indicated there may be a risk. That led to excluding feed crops from the label.

Shannon Sereda, senior manager of government relations and policy with the Alberta Wheat and Barley Commissions, agrees it’s a mysterious decision on the part of PMRA.

“Both the PMRA and EPA were reviewing the safety of lambda-cyhalothrin at the same time,” says Sereda. “The PMRA made the ruling that the product could be used on crops for human food, but not for feed use. The EPA reviewed their data and decided the product was safe for use on both food and feed crops.”

Sereda says the ruling that the insecticide cannot be used on crops for livestock feed is “unworkable.”

“So often it all depends on the cropping season and growing season conditions,” says Sereda. “Farmers just don’t know. They may seed a crop intended to be used for food processing, but because of weather or market changes six months down the road that crop could enter the livestock feed market. That’s why we say it is not a workable ruling.”

Sereda says the industry and commodity associations are asking the PMRA to hold off on a final decision until it has at least reviewed the same data set used by the EPA.

“We are not trying to interfere with the regulatory system, but we want to make sure all scientific data has been properly reviewed,” says Sereda.

She says if nothing changes before the April 29 ruling comes into effect, there are still many questions to be answered.

For example, what do farmers do with crops from 2022, still in the bin and on the farm, that may have been treated with lambda-cy products?

And particularly affecting the livestock industry, what about feedstocks such as corn and dry distillers grain produced in the United States, commonly imported for use in Canada? Would those feed products still be allowed?

Alternative products available

Western Canadian entomologists and agronomists agree that while the loss of lambda-cyhalothrin products for 2023 is a “great concern” it is some consolation for farmers to know there are alternative products to control pests on most crops.

John Gavloski, an extension entomologist with Manitoba Agriculture, Food and Rural Development, says producers must understand this is a temporary situation and not the end of lambda-cy insecticides.

“There seems to be a lot of misinformation regarding the lambda-cyhalothrin label amendments and resulting consequences,” he says. “We need to be careful not to spread myths that have been started and definitely do not want to imply the products have been banned or phased out.”

Gavloski says there are other synthetic pyrethroid products and chemistries to control most crop pests, but farmers will need to pay attention to label recommendations, product rates and timing, which may be different from what they are used to.

For example, alternative chemistries or products for canola might include deltamethrin (Decis, Poleci), permethrin (Pounce, Ambush, Perm-Up, Ipco Syncro) and cypermethrin (Up-Cyde, Ship).

Boyd Mori, a University of Alberta entomologist and assistant professor, says while it is difficult to predict pest severity for the coming crop year, it is expected some of the insect outbreaks in 2022 will persist.

“Of course, flea beetle is top of mind as it was a serious problem in many areas last year,” says Mori.

“Wheat midge has been on the rise in certain areas of east-central Alberta and Saskatchewan. Grasshoppers were a serious problem in parts of southern Alberta and Saskatchewan.

“Similarly, cutworms have been increasing in certain pockets. And diamondback moths don’t overwinter here, but with favourable conditions can be a problem. Farmers have to be prepared.”

Sarah Anderson, an agronomy manager with Saskatchewan Pulse Growers, says flea beetles, grasshoppers and aphids will continue to be a concern for Saskatchewan farmers in 2023.

“Thankfully, there are control options available. But farmers and agronomists need to be familiar with products to make sure they are used according to label recommendations.

“There may be changes in crop or insect staging and the best time to apply, so producers may need to be more creative to achieve proper control.”

In Manitoba, Morgan Cott, an agronomy extension specialist for special crops with Manitoba Crop Alliance (MCA), says farmers should look at older as well as new insecticide products available this year.

For MCA producers of wheat, flax, barley, corn and sunflowers, some of the key pests they’ll be watching for in 2023 include grasshoppers, European corn borer and army worms.

“For most pests on most crops there are effective alternative products available including some newer products,” she says. “Farmers will need to do their homework on which products will work the best.”

Cott did say one gap in the insecticide lineup if lamba-cy products can’t be used is one to effectively control lygus bugs on sunflowers. Otherwise, all other bases appear to be covered.

All four specialists say while it is comforting to know alternative products are available, the big question is whether they will be available during the growing season. Chemical companies say they will ramp up production, but only time will tell.

The post How to manage without lambda-cyhalothrin in 2023 appeared first on Grainews.

Pea aphids are so named because of their attraction to field pea plants but virtually any pulse crop, including lentils, faba beans, dry beans and chickpeas, and legumes such as clover and alfalfa can be a host. Scientifically known as Acyrthosiphon pisum, pea aphids basically suck the juice out of a plant’s leaves, stem or roots, which, in turn, can result in significantly lower yields due to reduced seed formation and smaller seed size.

“I like to say that pea aphids can suck the yield out of plants,” says Tyler Wist, a research scientist with Agriculture and Agri-Food Canada, who is based out of the Saskatoon Research and Development Centre. “For example, with (faba) beans the last few years, we’ve seen plants wilting under the stress aphids are causing. In 2018, here in Saskatoon, we had population counts of about 17,000 aphids on a single (faba) bean plant.”

Pea aphids are sometimes referred to as a cosmopolitan pest because they have a presence on every continent and often migrate from one region to another. They were first reported in the United States in 1878 and were first found in Canada near the turn of the century in the Ottawa region.

Wist says the pea aphid is in many ways a model organism. The sap it feeds on contains high levels of sugar but is poor in terms of other nutrients it contains. A gut microbiome helps convert that sugar into other nutrients it needs to survive.

Part of the challenge of dealing with pea aphids is that they are capable of reproducing extremely quickly, Wist explains. During the summer, female aphids can reproduce by means of parthenogenesis, a form of asexual reproduction akin to cloning. Their offspring are born with eggs that will soon hatch, which means a single female is capable of producing many offspring in a very short period of time.

“When they’re all female and they’re all giving birth to live young, they don’t get wings,” Wist adds. “They just sit there and keep feeding and have live young that don’t have wings. The populations can build up very fast because they’re all female and they’re all born pregnant, and within seven to eight days of being born that female who is pregnant starts having her own offspring. When plants start to (age), the aphids pick up on that and start producing offspring that develop wings when they reach their adult stage.”

Several factors determine threat level

How much of a threat aphids pose depends on a number of different factors including where you are, when you harvest and what kind of weather you receive, according to Wist.

For example, pea aphids are a perennial problem in many parts of Saskatchewan and Manitoba but are often an afterthought in Alberta. Wist says that may be because farmers in Alberta can often get their seed in the ground by early May and harvest that crop before pea aphid numbers really start to spike in late July or early August.

Precipitation levels can have a huge effect on pea aphid populations. In wetter years, they are more susceptible to developing fungus, which can significantly increase mortality levels.

Temperature also plays an enormous role in determining how much of a threat pea aphids pose. They tend to thrive when the average daytime high is around 20 or 21 C but have a tough time handling extreme heat. Wist says that could partly explain why aphids didn’t pose much of a threat last summer when the Prairies were in the grip of a heat wave.

“It was too hot in July for the pea aphid populations to really thrive because it was above their thermal tolerance levels. They couldn’t take the heat,” he says.

Wist stresses it’s far too soon to say what kind of a problem pea aphids could pose for farmers in the Prairies this season. If they’re going to blow in from elsewhere, then it will depend largely on weather and wind patterns, Wist says, who is part of a project studying wind patterns and their influence on aphid populations. Overwintering pea aphid populations in regions with extremely cold temperatures and heavy snowfall likely weren’t negatively affected this past winter due to the insulation provided by the snow.

What you can do

Wist’s advice to pulse growers is to start scouting for pea aphids beginning in early July and to use a sweep net as part of their efforts to determine if economic thresholds for the pest have been reached in their fields. He also recommends pulse growers try to cultivate beneficial insects such as lady beetles in their fields by leaving select areas near their fields to grow naturally.

“I’ve had growers share stories with me where lady beetles moved in and basically wiped out the pea aphid population,” he says.

Another effective mitigation strategy for growers is to avoid planting pulses late, which can put those crops into a more susceptible stage when pea aphid populations spike.

“Get your seed in the ground in good time and try to race against time to beat those pea aphid populations,” he says.

Even if pea aphids may not appear to be a problem early on, Wist says it’s critical for growers not to become complacent.

“I think the biggest thing they can do is watch the timing of their crop and if the crop is at a susceptible stage and they can see they have strong pea aphid pressure then use those economic thresholds they have and spray if they need to.”

The post Don’t let pea aphids suck the yield out of your plants appeared first on Grainews.

The province on July 21 announced an 18-month prohibition on sales and use of second-generation anticoagulant rodenticides (SGARs).

The second-generation products are “more powerful” than the previous generation and increase the risk of secondary poisoning of owls and other animals that eat poisoned rodents, the province said.

Uses that support “agricultural production and food safety” will be exempt, the province said, as will uses by food processing and storage facilities, grocery stores and restaurants as well as hospitals and other health services.

Farmers and ag operators, specifically, will need to show “proof of qualifying agricultural status” and follow integrated pest management principles including “prevention and full consideration of alternatives” in their use of SGARs.

Consideration of alternatives, the province said, means treating the use of pesticides as a “last resort when other measures are not effective.”

SGARs include active ingredients such as brodifacoum, bromadiolone and difethialone, while first-generation anticoagulants include warfarin, chlorophacinone and diphacinone.

All anticoagulant rodenticides were subject to more strict label requirements effective at the end of 2012, following a 2010 re-evaluation by Health Canada’s Pest Management Regulatory Agency.

According to Health Canada, the SGAR products “tend to be more acutely toxic than the first-generation” and generally provide a lethal dose after a single feeding, but don’t cause death for about five to 10 days, so animals continue to feed on them in the meantime.

First-generation products generally must be ingested for several days to provide a lethal dose, as they’re less acutely toxic and more rapidly metabolized and/or excreted.

“We share the concerns of many British Columbians that rodenticide use is harming, and too often killing, birds, pets and other wildlife,” Environment Minister George Heyman said July 21 in a release.

“That is why we are taking action to reduce risks, conduct a review and step up our efforts to reduce unnecessary pesticide use, rather than safer alternatives.”

— Glacier FarmMedia Network

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