Monitoring for CRW adults using sticky traps is an effective tool for flagging fields that have suspected Bt resistant rootworm populations if placed in fields planted with a CRW Bt hybrid. The traps can also provide insight into what the risk of rootworm injury will be in next year’s corn crop if that field is in continuous corn production. Higher beetle populations this year mean more eggs being laid in the soil that will hatch into larvae next spring.

If sticky traps catch an average of two or more beetles per trap per day or if easier – if after seven days in the field, each of the four traps monitored catch 14 or more beetles – that field is at high risk (Figure 1). If these traps are in a field that was planted with a CRW Bt hybrid, this indicates that a lot of rootworms survived feeding on roots expressing Bt and could be a resistant population. These fields need to be reported to your seed provider and myself to test for potential resistance.

If the field is not planted to a CRW Bt hybrid but will be going into corn again next year, it will need some form of protection at planting, either by using a soil applied insecticide, planting a CRW Bt hybrid or consider rotating that field out of corn next year to avoid rootworm injury. Crop rotation at least once every four years is also a more sustainable management practice to help address resistant rootworm populations. More information on trapping instructions can be found in this Field Crop News Article: https://fieldcropnews.com/2024/06/corn-rootworm-trap-participants-needed/

WESTERN BEAN CUTWORM

Western bean cutworm (WBC) moth flight has begun with a few traps are catching lower levels of moths. Don’t assume low moth counts this early means low risk. With such variable planting dates and growth stages in every region, these early moths may unload a lot of eggs in only a few of the more advanced fields out of desperation. Scouting is advised in the earliest planted fields to check for egg masses. If five per cent of the plants scouted over three scouting periods has egg masses, the field will need an insecticide application. Remember that WBC larvae need at least a tassel developing in the whorl to survive in the absence of an ear of corn, so focus on fields in later growth stages first. Fields younger than V8 are less at risk right now. Later planted fields will be at higher risk when peak moth flight takes place late July to early August. More information on moth counts can be found on the Great Lakes and Maritimes Pest Monitoring Network.

EUROPEAN CORN BORER

With European corn borer (ECB) populations becoming less susceptible to Bt corn, we need to start scouting for unexpected injury in Bt corn.

Eastern Ontario needs to be extra vigilant as they neighbour provinces with known resistant populations but all growers in Ontario should start this practice. Scout between 10 to 20 areas of the field after V6 stage, looking for signs of ECB injury including leaf or whorl feeding, frass and stalk tunneling in the midrib or at the leaf axils (Figure 3), bent or broken stalks and the tell-tale sign broken tassels. Any signs of ECB feeding injury in Bt fields should be reported to your seed provider and myself. Don’t assume the injury you see if on only refuge plants.

To help reduce the spread of resistance, shredding stalks during or shortly after harvest will need to become standard practice again to kill any overwintering ECB larvae in the corn stubble left after harvest. More information on recent resistance detections and signs of ECB injury can be found on the Canadian Corn Pest Coalition Website.

More information on biology and management of any of these pests can also be found on Ontario CropIPM and Crop Protection Hub. As always, critical pest updates will also be available through the rest of the season on Field Crop News.

– Tracey Baute is an entolmologist with OMAFA’s Field Crop Team. This article was originally posted at Field Crop News website.

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Chris Gillard, associate professor in the department of plant agriculture, leads an agronomy and pest management program and is focused on collaborating with growers to ensure the research is in line with their top management questions and concerns. 

He presented his recent research at the Ontario Bean Growers research day at the organization’s Huron Research Station in Exeter. 

[RELATED] Concerns grow over control-resistant pests

White mould

In a recent provincial survey, three-quarters of bean growers ranked white mould as their biggest problem. 

When a grower is contacted by a company claiming to have a new product to control the disease, they typically ask Gillard for an independent assessment. 

Why it matters: Researchers are evaluating pest management products and determining their most effective timing so growers can maximize return on investment and yield.

“We are looking at new products all the time and we carry out extensive testing,” says Gillard, noting at least four data points are generated before judgment is passed on a given product.

Based on results from 2018 to 2022, his research indicates six new products – Astound, Cotegra, Delaro, Maxim, Miravis and Priaxor – are average performers.

Three alternative products – Double Nickel, Oro-solute and Oxidate – have been deemed poor because they performed no better than if plants were untreated.

Gillard’s research confirms that Allegro and Propulse remain the top recommended fungicides to control white mould in dry beans.

Both products have a drastic impact on the disease, reducing severity by 34 to 50 per cent, increasing yield by 50 to 70 per cent and increasing grower return on investment from $335 to $1,040 per hectare.

“The survey shows growers are using our recommendations and this means that the information is valuable and the research is working,” says Gillard. “Finding out that a product doesn’t work is just as useful to growers as knowing what does work and how well it performs.”

Since the fungicide performance research is funded by bean growers, Gillard considers the data to be owned by growers and does not allow chemical companies to use his name or data for marketing purposes.

Western bean cutworm

Western bean cutworm is another major management concern. The moths are attracted to dry beans after the corn crop tassels.

“It’s a really difficult pest to deal with in beans because it’s basically impossible to scout for in the field,” Gillard says. “You have to look for the damage it causes and not the pest itself.”

He says growers will see some cutworm management recommendations soon, as M.Sc. student Josee Kelly is currently completing her second year of field trials. Her work is focused on infesting plots with western bean cutworm larvae at different stages and applying insecticides at different times to determine the most effective time for application.

Kelly is also using data from the provincial western bean cutworm trapping network and assessing counts by temperature and soil type to determine correlations.

Her analysis will be complete and summaries of her graduate study will be ready to share with growers in April 2023.

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“We want to go strip till, because that’s what we’re evaluating it for, growers who want to go strip till or minimum till. We want to be closest to the practices that growers are using or will use, or will transition into once they have options,” says Todd Cowan, station manager and weed science technician at the University of Guelph research station. The station hosted a recent Ontario Bean Growers research day, the first in-person event there in the past 18 months.

Why it matters: With few options for weed control, researchers are examining various tilling methods to help dry bean growers maximize yields. 

Dry bean growers, however, still lack herbicide options to help with weed control in minimal or strip till. 

There is a lack of pre-plant treatment options to help control Canada fleabane, which has become a problem due to glyphosate resistance. 

There has been a minor use registration submitted for Eragon used on adzuki beans, which could help for growers of that type of bean, although adzukis interact much differently with herbicides than other dry beans. Eragon is a Group 14 herbicide used pre-plant in soybeans and other crops.

Tergeo, another Group 14 herbicide currently in the approval process for other crop uses, could be used for other classes of edible beans, including as a tank mix down the road, if it is registered, says Cowan.

“There are a number of different options available to growers who use conventional tillage, but in conservation tillage, there’s a gap there.”

Cowan says they expect to have more research in the future on desiccants. The ability to kill green matter before harvest on a field of dry beans is helpful to ensure a clean harvest and there have been increasing restrictions placed on what can be used in the past few years. For example, the marketplace has said it doesn’t want glyphosate used as a desiccant in dry beans.

Cowan talked about some of the research conducted at Centralia by Dr. Peter Sikkema, who was unable to attend the event.

Chris Gillard, a professor at the University of Guelph’s Ridgetown Campus, also used strip till for fertilizer and cover crop trials in dry beans at Centralia.

“We’re getting more and more strip tillage equipment here that can handle cover crops. It fits nicely for dry beans,” he said.

Gillard is looking to do more research on cover crops and dry beans and it could include dry fertilizer research too. Dry beans are one of the earliest harvested crops in the fall and don’t leave much residue, so they are a prime candidate for cover crops.

“I think they respond well to have some kind of a fibrous root system before them in the rotation,” says Gillard.

The Centralia Research Station has a new vertical tillage machine with the ability to plant a cover crop, so he says there are more capabilities to do such research.

“The end users in Britain would love it. If you can show that you are placing your fertilizer below the soil line and protecting it from being lost to surface erosion, if you can show that you’re using cover crops to help manage weed control, and to help reduce soil erosion, it just makes sense for this crop,” he says.

Western bean cutworm research

There are years of data from western bean cutworm moth traps across the province that haven’t yet been analyzed, including hundreds of thousands of data points. 

“Nobody’s looked at how do they relate to growing degree days or soil type or growing season,” says Gillard.

That job is falling to Josee Kelly, who recently started a master’s degree at the University of Guelph’s Ridgetown Campus, working with entomologist Jocelyn Smith. She helps Smith maintain a colony of 8,000 western bean cutworm larvae at Ridgetown.

Kelly is also researching how Coragen could help control western bean cutworm in dry beans. The insect has become the most economically harmful pest in corn in Ontario and it also has created damage in dry beans. 

However, there’s little information on control in dry beans, which Kelly aims to change.

She’s brought larvae and infested a block of dry beans, with 11 different rates of infestation and insecticide applications.

She’s also looking to see if pathogenic nematodes could work to help control western bean cutworm in dry beans.

The post Researchers expand tillage options related to dry beans appeared first on Farmtario.

Peak flight occurred the same week for both field corn and dry bean traps while sweet corn traps peaked a week earlier. As always, dry bean traps captured more moths during that period than traps next to field and sweet corn fields (Figure 2 below).

When we look more closely at trap counts by county however, peak flight timing varied and wasn’t entirely dependent on geography or degree day (DD) accumulation (Figure 3 below). Some counties peaked the week of July 22-28, while others peaked the week of July 29 – August 4th. Grey county observed peak flight later than all other counties across Ontario (August 5th – 11th). Several DD models have been developed to help predict WBC flight activity. Hanson et al. 2015 is considered the most reliable so far by many states. It uses 3.3C as the base temperature, calculating degree days starting on March 1st. According to the model, 50% of moth flight (peak flight) occurs when 1502 DD have been accumulated. Using weather data and trap counts for Ontario this year, the model accurately predicted peak flight for some locations but not all. Table 1 shows the predicted versus observed peak flights by county across Ontario. Predicted peak flight was too early or too late for some counties. We hope to make refinements to this model to predict WBC development more accurately in Ontario. This will help improve both scouting and application timing to enable the most effective management possible.

To read the full Field Crop News report for Aug. 25, click here.

The post Flight of the western bean cutworm appeared first on Farmtario.

Western bean cutworm is the insect pest considered to be the most economically harmful to Ontario’s corn crop and companies are scrambling to get the Viptera trait into their hybrids. NK already has the Viptera trait in a range of hybrids because Syngenta owns it.

NK has packages that allow farmers to choose between above-ground insect protection, below-ground insect protection, or both, said Gustavo Gonzalez Roelants, the company’s corn product placement specialist, during the recent Syngenta Media Summit.

Agrisure Viptera is the company’s above-ground trait protection system and Agrisure Duracade is for below-ground use.

NK is the only company in the market with above- and below-ground protection including western bean cutworm protection, said Gonzalez Roelants.

Syngenta’s NK brand also continues to roll out more options in its soybean lineup.

Matt Hooyer, soybeans product placement specialist, said the company believes the strength of its germplasm allows it to move new traits into its lineup, including Enlist E3 and Roundup Ready2 Xtend with glufosinate resistance, without sacrificing resistance to diseases.

“We can be nimble in herbicide traits without sacrificing defensive traits,” he said.

For example, 52 per cent of the company’s Enlist E3 soybeans have the Rps3a genetic package that includes resistance to Phytophthora root rot.

Screening for diseases continues to be a focus, whether it includes Phytophthora root rot, white mould or sudden death syndrome, said Hooyer.

The company has launched several new soybean varieties including S12-M5X, S20-E3, S18-K2X and S12-J7, all with the Rps3a defensive trait package and available in E3, Xtend and conventional options.

Syngenta also puts particular focus on its foodgrade soybean varieties.

The post Syngenta maintains WBC trait advantage appeared first on Farmtario.

On this edition of Field Talk, Farmtario reporter Jennifer Glenney, speaks with Matt Rundle, sales agronomist with Harriston Agromart, about Western Bean Cutworm scouting.

Rundle says the ideal timing to scout this nasty pest is now. Peak moth flight, and egg masses are the best things to look for within grower’s fields. Western Bean Cutworm can lead to heavy damage so proper scouting is vital.

The post VIDEO: Western Bean Cutworm appeared first on Farmtario.

That said, Tracey Baute, field crop entomologist and WBC expert with the Ontario Ministry of Agriculture, Food and Rural Affairs, says several factors have combined to make accurate impact predictions difficult.

Why it matters: Planting delays experienced in the first half of 2019 mean crops are developing when WBC is at its most aggressive. Negative impacts could be seen despite current low pest numbers.

Crop development ill-timed

Ineffective pheromone lures in some of the traps used in the WBC trap monitoring were a problem early in the growing season. Some traps worked fine, says Baute, while others did not effectively attract migrating moths, making it difficult to draw accurate population estimates.

“That added an additional issue with us comparing previous years [ …] It got sorted out before we reached peak flight,” she says.

Slow growth early in the planting season also meant the WBC trap network, as described by Baute in an article for Field Crop News, did not reveal its first moth until the second week of July — a time normally considered close to WBC’s peak flight period.

However, Baute says the main danger in 2019 stems from late planting. Corn and dry bean crop development now line up with WBC development, posing a greater risk of damage from both the pest itself and the diseases following in its wake — notably DON and other fungal pathogens.

“They may not have as long a time to feed on the ears as in some years. They didn’t really get in the fields until August,” says Baute, but some ear feeding may have gone unnoticed thus far.

“There’s always going to be feeding even if they spray. There will be some that survive,” Baute says. “Damage really doesn’t show up until defoliation of the plant.”

She also reiterates no clear hot-spots have been identified yet, but the aligning of WBC and crop development means moths can pick and choose their locations more easily. Rising yearly temperatures also allow the pest to overwinter closer to Ontario, giving it yet more flexibility within the province.

“[This] also highlights not to rely on trap counts. You still have to scout because the dynamics of what’s going on in the field could be different then what the trap is telling you,” she says.

Unknown factors might be suppressing WBC

WBC numbers have been shifting downwards over the last two years. Indeed, Baute says both the number of egg masses and the remnants of egg masses have dropped. This indicates something is affecting the ability of WBC to lay eggs.

“We are not sure […] We’re just not seeing the egg masses as prevalent as we usually do. It’s an effort to find enough compared to previous years,” she says. “If you scout frequently enough you should still see the presence of egg masses. In some cases, they weren’t there.”

For her part, Baute believes the missing factor is likely greater pressure from bio controls – namely predatory insects such as ladybugs, lacewings, and others. However, more investigation is required.

Earworm numbers rising

While western bean cutworm numbers appear to be dropping, the last few years have brought an increase in corn earworm populations. This pest comes from the United States and lays its eggs directly on ear silk, which Baute says makes them very difficult to see.

As with WBC, the late 2019 planting season also provides greater opportunity for the pest to develop.

“That’s another pest that’s likely going to start playing a role in ear damage in the fall. I think we’re going to see it more often,” she says. “It’s not just a sweet corn issue anymore […] If we have years where we delay grain corn planting, we are going to see more risk.”

The post Western bean cutworm laying low so far appeared first on Farmtario.

Why it matters: The trap network enables OMAFRA and participants to monitor peak flight timing of corn pests, helping growers and scouts identify timing of egg laying and monitor thresholds.

The trap network began back in 2010.

Chris Difonzo from Michigan State University and Tracey Baute, OMAFRA entomologist, began putting up traps in 2006 and 20007 to detect the arrival of western bean cutworms (WBC.)

Baute began to coordinate more traps across the province, and into Quebec.

By 2010, she started the WBC Trap Network, including more than 600 trap sites each year for the past three or four years.

“It was only successful because of the trap data that came in from all the trap participants, including the lead corn entomologists from Ontario, Quebec and Michigan, as well as the corn company agronomists, certified crop consultants and growers who monitored their traps too,” says Baute.

The network received funding from Grain Farmers of Ontario and the Ontario Bean Growers’ Association to put out the traps, and years following it became a project.

“It worked so well we kind of just kept it going regardless of funding because we felt there were enough companies, agronomists and growers themselves to put up the traps, monitor them and provide the data,” says Baute.

The network began with Quebec, Ontario and Michigan, Ohio, New York and all the maritime provinces being the recent additions. Invitations have been extended to the U.S. eastern states Maine, New Hampshire, and Vermont.

Other corn pests were added to the program after the corn earworm caused extensive damage across Ontario in 2018. Bt resistance in European corn borer, found in Nova Scotia, led to its inclusion.

“We have added five different corn pests as a starting block. If there’s an opportunity we may look at adding more pests or more crops to strengthen our coordination and detection abilities,” said Baute.

The six pests that can be recorded through the program include the western bean cutworm (WBC), European corn borer (both the New York and Iowa strain) (ECB), corn earworm, black cutworm, true armyworm, and fall armyworm. Each requires different traps and monitoring frequency, depending on region.

As well, deadlines for trap set-up vary pest to pest. The ECB traps are to be up in the middle weeks of May, to be able to capture the first generations of moths. WBC traps are to be up by the end of June to catch moth peak flight.

Any individual is welcome to participate in the pest tracking.

“We are not limiting anyone to trapping, [but] right now we don’t have the funding in place to provide traps for these additional pests to participants, but we do take their data and map it … to show what the pest is doing across the different regions.”

Geographic Information Specialists (GIS) do the mapping of the trap data.

Jennifer Birchmore, senior GIS specialist with OMAFRA has been taking weekly trap data spreadsheets and creating interactive maps.

“We did bring her group on board about five or six years ago, but that has enabled us to do interactive mapping instead of a static map being published each week,” said Baute

WBC scouting tips

Western bean cutworm prevalence for the 2019 season is an unknown due to the late and cold spring in much of Ontario.

Peak flight for moths is directly correlated with the accumulation of growing degree days (GDD).

Across the whole province the average peak flight timing is commonly the third or fourth weekend in July. By region, Essex County experiences peak flight in the second week of July, southwestern Ontario experiences it the third week of July and Central Ontario experiences it in the first week of August.

With the lack of GDDs Ontario has experienced thus far, there may be mixed results.

“This kind of year is a bit of a guess, as GDDs are slow, there may be a delay in peak flight for western bean cutworm, but there is probably also going to be a delay in peak tasseling,” says Tracey Baute, OMAFRA entomologist.

Some regions may have perfect alignment of tassel and flight while others may not.

Damage will be a mix this year between crops – as corn gets too advanced or not enough corn is present to maintain the population, the moths will migrate to dry beans, says Baute.

The pest damages crop quality more than yield.

“WBC feeding on corn can help introduce and encourage the growth of DON and different mycotoxins in corn; dry beans you can actually see pod disease harm.”

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However, Dave Hooker, of the University of Guelph’s Ridgetown College, says that historical monitoring of mycotoxin levels by the Ontario Ministry of Agriculture Food and Rural Affairs shows that there are definite hot spots in the province.

There are also hybrids that are more susceptible, he said, no matter what seed companies tell you.

Why it matters: Corn mycotoxin levels are an important determinant of quality. Increasingly farmers are spraying insecticides to protect corn from insects that cause wounds that result in mould and fungicides to protect from silk channel infection.

Hooker spoke at the recent Bayer CropScience Dead Weeds Tour near Guelph.

He worked on a model for corn similar to the DONCast system for wheat that predicts mycotoxin pressures based on weather trends, but it didn’t work out.

The researchers looked at corn samples, weather history and production history around those samples and tried to create a model that could help predict mycotoxins in corn, but “I was never happy with the DONCast predictions for corn,” he said.

There are several other factors involved with corn that aren’t involved with wheat and barley, especially the impact of seed pressure on corn mycotoxins.

The best information has resulted from high corn mycotoxin levels seen in 2006 and 2011.

The good news is that the disease can be managed and therefore, the risk from mycotoxins reduced.

High levels of mycotoxin in corn are especially a concern when feeding pigs and poultry. High levels of infection in corn can result in lower gain in pigs and abortions in sows.

Corn high in mycotoxins can be hard to market.

In 2011, 24 per cent of 1,500 corn samples taken around Ontario tested over two parts per million, well over the concern level of one part per million.

Mycotoxin levels in 2012, 2013 and 2014 were over two parts per million less than 10 per cent of the time and in 2015 over two parts per million five per cent of the time. In 2016 and 2017 levels were high again, he said.

All those years show pockets with high levels of mycotoxins.

“We have to stay up on our game in order to manage this,” he said.

One of the first places to start is in managing hybrid selection.

Dr. Art Schaafsma’s group at Ridgetown College looked at 30 corn hybrids over three years. It showed some hybrids were quite sensitive to mycotoxins.

“The hybrid is definitely important. If you are a hog producer with a history of high DON levels on the farm, I would suggest to talk to your seed dealer for hybrids with a fairly low risk of accumulation.”

DON is deoxynivalenol, one of the common mycotoxins that occur in grains.

Hooker said hybrid differences year to year are too great from the Ontario corn hybrid trials and so corn seed companies haven’t had the confidence in the numbers to make them public.

Growers need to manage the pathogen, the host, or the environment in order to break the ability of the pathogen to grow.

Fusarium graminearium enters the corn plant in several ways. The spores land on the silks, called silk channel infection. Luckily the time of infection is only from when the silks emerge until they brown, so the risk will have a lot to do with the environment.

Spraying for control of silk infection with products like Proline ends when the silk browns, although the plants can also still be sprayed for other reasons.

Some years, especially dry ones, slow pollination can mean a longer risk period for fusarium.

Wounding is the second point of infection, which can be from insects, hail or application of late nitrogen. The wound has to be on the cob.

It’s the silk channel infection where fungicides are most useful, not the wounding, Hooker said.

At harvest time, you can identify how the disease entered the ear. Silk channel infections are mostly seen closest to the tip of the cob. Infection from wounding is more variable across the crop.

Insecticides are the other way to protect a crop – by limiting the insect wounding of the cob, especially from Western Bean Cutworm (WBC), not considered the largest economic-impact pest in the province.

Luckily, the WBC pressure appears to be average or lower this year, compared to other years.

The only insect resistance trait that works on WBC is Vip3. The Cry1F traits in most corn provide no protection from WBC.

How to scout for WBC

Don’t spray on WBC moths. Spray according to egg counts from scouting begun at tasselling. Find 20 plants in five areas of the field and if there is greater than five per cent of counts with eggs on them, it would trigger a spray decision. Scouting is also cumulative. If it’s one per cent on the first scouting trip, and three per cent five days later, then that means four per cent is counted.

“We think if a hybrid is quite sensitive then we should be reducing that threshold to two per cent, especially during favourable weather conditions at silking.”

Favourable weather conditions include warm foggy mornings.

The post Managing corn mycotoxins needs scouting, hybrid choice appeared first on Farmtario.

Why it matters: Scouting for Western Bean Cutworm (WBC) is much more challenging in dry beans than corn, so knowing the status of nearby corn fields and increasing moth trap numbers in bean fields are important.

WBC have little impact on yield in Ontario – the problem is that their feeding on cobs lets in moulds that increase mycotoxin levels in corn, making the crop potentially less saleable or downgraded in quality. In dry beans, however, the cutworms burrow into the pods, said Tracey Baute, OMAFRA’s field crop entomologist.

Dry bean fields are most at risk once the corn is past full tassel stage.

“If adjacent corn fields reach threshold, it’s likely the dry bean field will too,” said Baute at FarmSMART in Guelph. She called scouting for WBC in dry beans “very difficult” because they lay their eggs under the leaves in beans, and deep within the canopy, whereas they lay on the upper leaves of corn and can often be seen easily.

Look for small holes in pods. Scout 10 plants in 10 areas of a dry bean field during early pod stages. Pod feeding usually happens 10 to 20 days after peak flight.

Researchers are still learning about when to spray WBC in dry beans, and as a result there aren’t yet good integrated pest management recommendations.

Michigan researchers say if there are more than 150 moths in a trap, they will be highly likely be a need for dry beans to be sprayed, said Baute.

The good news is that control is easier in dry beans than in corn.

Meghan Moran, OMAFRA’s edible bean specialist said that cranberry beans appeared to be the most affected, because when tiny holes are made in the bean pods, the oxygen level changes and the cranberry beans become discolored. That means higher “pick” levels, meaning amounts that have to be sorted off and are discounted.

Cranberry bean growers may need to be more vigilant than other edible beans growers, she said.

Researchers and farmers, however, continue to learn how to manage WBC in corn, as the insect is found across more of Ontario’s corn growing area.

Here is some of the latest thinking and some reminders about managing WBC in corn:

• Moths fly at night. Michigan State University found the bulk of flights occur between 1 a.m. and 3 a.m.
• The moths have easily identifiable markings: white margins along the forewings, with a solid circle or and then a boomerang or comma shape further back. However, once they’ve been stuck in a pheromone trap for a few days, they tend to have rubbed the scales off their wings, and there also the markings. Don’t think they aren’t WBC moths.
• Scout 10 plants in ideal growth stage in 10 areas of field, so 100 plants each time, looking for egg masses. It’s ideal when you can get the sun between you and the leaf in order to illuminate the egg masses.
• The threshold for spraying for WBC has continued to evolve. The now accepted threshold, said Baute is a cumulative five per cent threshold, meaning when five per cent of the plant in a two or three-week period have had egg masses and/or small larvae. If a hybrid is susceptible to fusarium, the an even lower threshold is likely needed.
• Make sure to rotate modes of action of insecticides in order to decrease the likelihood of the Western Bean Cutworm developing resistance. There are four insecticides used for WBC control. Two, Matador or Silencer (pyrethroids), and Voliam Xpress (pyrethroid and diamide) are both being re-examined by Health Canada. The other two are Coragen (diamide) and Delegate (spinosyns).
• Remember that the Cry1F Bt traits have no effect on WBC. Only corn with the Vipterra traits have effective control of WBC.

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