Soybean aphids colonizing on V stage soybeans

Soybean aphids initially start to colonize in pockets of early planted fields. Several plants in these pockets can have hundreds, even thousands of aphids on them at first.  Walk a few meters away from these pockets and you won’t find any aphids.  Once the aphids start to get crowded on the plants in these pockets, they produce aphids with wings so they can spread out some more, colonizing new plants in the field.  Populations then change from several hundred per plant in small pockets in the field, to only a few per plant on more plants across the field.  This continues to occur, particularly when the plants are still in their V stages.  Insecticide trials have not been able to show any yield response to sprays done on these V stage infestations.  In fact, a spray application during the V stages can actually cause problems as it easily wipes out the natural enemies that are trying to do the work for you.

During the R1 to R5 stage of soybeans, an insecticide application is required once 80% of the plants in the field have at least 250 aphids per plant and it is apparent that the population is on the increase.  Experience has shown that natural enemies can keep the aphid population fluctuating  above and below the threshold.  This fluctuation means they are working hard for you, trying to take down the aphid population. Only when you see the aphid population continue to rise instead of fluctuate, do you know that the natural enemies are not plentiful enough to keep up.

Aphid Advisor app

To help take all of this guess work out of all of this, we (University of Guelph & OMAF and MRA) have developed the free “Aphid Advisor” smartphone app” available for both Blackberries and IPhones available at: http://www.aphidapp.com/  When your soybean plants are in the R1 to R5 stages, just input the average number of aphids per plant from at least 10 random plants i the field.  Then input the number of natural enemies you are seeing.  The Aphid Advisor will tell you (based on proven field trial work done in Ontario) if you need to spray, wait a few days and re-scout, or don’t spray..based on thetype and ratio of natural enemies to soybeans aphids that are present in the field.  And if you “Submit the Data” once you are done, your results will be graphed with others in each county so everyone can see which counties have needed to spray or didn’t have to.

If you do need to spray, refer to Publication 812 for recommended products.  I do not recommend the use of a neonicotinoid foliar insecticide (active: imidacloprid or thiamethoxam) on soybeans, particularly when there are flowers on the plants, as recent studies indicate that bees and other pollinators frequently visit soybean plants during flowering.

Seed corn maggot can feed on the cotyledons.  Their feeding tends to leave small caverns and tunnels on the cotyledons.  These tunnels however can be along the edge of the cotyledon, making it look like something with much bigger “jaws” has taken a bite out of it.  To know for sure if it is seed corn maggot damage, you need to dig the seedling plant out of the ground and look for the tell tale signs of mining along the stem of the seedling.

Seed corn maggot injury to soybean seedlings

The small white maggot could also still be present in the seed or stem.  Cruiser does work well on seed corn maggot though so if feeding is extensive in a Cruiser treated field, it is likely due to another pest.  Fields at high risk of seed corn maggot injury are those that were freshly tilled with heavy crop residue present, had recently applied manure, were deep planted or have had poor emergence from cool, wet conditions.

Bean leaf beetle can also feed on the cotyledons.  I like to think of them as meticulous feeders, since they tend to eat in neat little circles, scraping off the surface of the cotyledon.  These circular patches on the surface of the cotyledon can blend into each other and start to resemble the same kind of damage the slugs can make though.  Even if the soybeans have been treated with Cruiser, you will see some feeding, as the beetle needs to take a bite of the plant before it dies.  If populations are high enough, the damage can be quite noticeable. Fields at high risk are those with a history of infestations and those neighbouring alfalfa fields.

BLB damage on cotyledon (Photo Credit: Ron Hammond, Ohio State University)

You might see a few adults present on or near the plants while scouting, though you have to look at least a metre ahead of your step, as they tend to run and hide or drop down into cracks in the soil as soon as they sense your approach.  In fields not treated with Cruiser, the threshold is 16 beetles per foot of row during the seeding stage and especially if plants are being cut off.  Foliar control options can be found here: http://www.omafra.gov.on.ca/english/crops/pub812/2blb.htm

Slugs are the last of the primary culprits that can feed on cotyledons.  They have a radula for a mouth..picture dentures for the upper jaw that are filed to a sharp, fine saw-toothed blade.  So they essentially hack at their food, tearing small chunks of plant tissue away as they feed. Less scraping, more hacking. Cruiser seed treatment does not work on them as they are not insects.  A tell tale sign that slugs are the culprit is to look for a silvery trail (slime trail) left on the surface of the plant or nearby soil surface (though a recent rain will wash off the trails).

Slug injury to cotyledons (Photo Credit: Ron Hammond, Ohio State University)

You can also leave a few small pieces of plywood or shingle on the soil surface for a day or two and return to turn them over and see if slugs are underneath.  Fields are risk are those with history of slug damage, fields following wheat with red clover, fields with a fair amount of trash on the soil surface particularly close to the seed bed and of course, wet field conditions.  Slugs present in the spring are the same slugs that were present last fall so wet fall conditions help build populations for the following year.  Unfortunately, there is no economically feasible control for slugs, other than moving trash away from the seed bed before planting.

Once the unifoliate and trifoliates start to emerge, the diagnosis becomes much easier.  Seed corn maggot really only feed on the leaves when they are still just developing and tend to leave a “snakehead” shaped seedling remaining. Bean leaf beetles perfect circular holes become very apparant on the leaves while in the case of slugs, the leaves start to look skeletonized or look similar to hail damage with leaf tissue missing while the leaf veins remain.

I have had reports of armyworm being present in many wheat fields in Chatham-Kent though not at threshold yet.  Another report came in just yesterday of a field in Harrow that was near threshold, though the armyworm were still small and had not done much leaf feeding yet.  It doesn’t take long for these smaller larvae to grow and  start clipping heads though so don’t underestimate these small larvae.  They are actually the best size to get good control of.  If armyworm reach threshold (5 per square foot) in wheat, control is advised, as long as most of the larvae are still small.  Once they get to be bigger than an inch, they are more difficult to control.  Also pay particular attention to the pre-harvest intervals as the PHIs for the products registered in cereals range from 14 to 28 days to harvest.

This does not mean however, that everyone should tankmix some insecticide in with their fusarium control this week “just in case”.   Tankmixing “just in case” is NOT sound integrated pest management.  Applying insecticides when they are not necessary can lead to mother nature biting back.  These profolatic sprays kill off non-targets including natural enemies of our plant pests which take a lot longer to build up again in numbers to help control the pest.  It starts a cycle where, in the absence of any natural enemies, the pest becomes a problem, year after year.  You will also fail at effectively controlling either armyworm or fusarium this way.  Fusarium and armyworm require very different spray strategies.  The nozzles, nozzle configuration, water volumes, and pressures are different for fusarium versus armyworm control.  For armyworm control, you want to use water volumes of at least 20 gallons of water per acre, with nozzles that give a medium to fine droplet size, with best control found when nozzles are set at 30 degrees forward and 30 degrees back to get good coverage down into the canopy of the crop.  Fusarium nozzles are set at a very different angle to target the wheat head only which is very important for fusarium control but won’t get to the armyworm feeding below.  And you must spray for armyworm at night when the insect is actively feeding on the plants.

Wheat is not the only crop at risk from armyworm.  Forages and corn also need to be scouted these next few weeks.  I have not had any reports of armyworm in forages or corn yet.  But that does not mean they are not there.  Everyone needs to take a look at these crops at risk.

Scouting Thresholds and Control Options for Wheat: http://www.omafra.gov.on.ca/english/crops/pub812/4aw.htm

Scouting Thresholds and Control Options for Forages: http://www.omafra.gov.on.ca/english/crops/pub812/3aw.htm

Scouting Thresholds and Control Options for Corn: http://www.omafra.gov.on.ca/english/crops/pub812/1aw.htm

Brown marmorated stink bug adult (Photo Credit: Stephen Ausmus, USDA-ARS)

Brown marmorated stink bug (BMSB) is our newest pest of concern for Ontario agriculture.  Though we have not detected it yet on any of its crop hosts, we have confirmed it has established breeding populations here in Ontario and is successfully overwintering in homes in Hamilton, Toronto, Newboro and most recently Windsor.  It is likely overwintering in other urban centres but has not been properly identified yet.

In the next few weeks, BMSB will be moving out of their overwinter sites and move onto their host plants. BMSB has a countless number of host plants to choose from. Early in the season they will move to ornamental host plants like buckthorn, tree of heaven and English holly.  They may then turn to fruit and veg crops early to mid summer before finally moving into field crops.  Field crops at risk include corn, soybeans and edible beans but these crops will likely to be most at risk once they are in their reproductive stages (ie when there is an ear or pod).

We have put together a flyer to help with identification, as there are some  other insects that may be confused for BMSB:

English – BMSB-flyer                  French – BMSB-flyer

If you think you have found BMSB, call the Agriculture Information Contact Centre at 1-877-424-1300 or send an email to ag.info.omafra@ontario.ca.  Also visit our BMSB website at: ontario.ca\stinkbug for additional photos, infosheets, ID postcards and potential management options.

This same cool, wet weather can impact the natural enemies of other pests too.  Cereal leaf beetle and alfalfa weevil are two that can get out of hand after a cool wet spring.  Scout now for these two pests, particularly in fields with a history of infestations.  Information on cereal leaf beetle scouting can be found at: http://www.omafra.gov.on.ca/english/crops/pub811/13cereal.htm#clbeetle and alfalfa weevil at: http://www.omafra.gov.on.ca/english/crops/pub811/13forage.htm

Factors that may contribute to the issue: Seed lubricants (ie talc or graphite) are abrasive and rub the insecticide seed treatment off of the seed and carry it into the air. Negative vacuum air planters likely contribute to this by exhausting the contaminated dust into the air, instead of onto the ground like other planters do.  Dry, windy and warm weather also likely played a role, both for early than usual bee foraging activity and helping to carry the dust further outside the field.  This however does not mean that this issue could not occur under different weather and field conditions.

Best management practices to help mitigate the risk to bees include:

1. Communicate with beekeepers who have hives in your area.  Bees can forage up to 5 km from their hives and likely venture in and around your fields. Let the local beekeepers know when you plan to plant.  There may be steps that they can take to protect their hives during planting.
2. Adjust time of planting. If there is an opportunity to plant in the early morning or evening on windy days, when bees are less likely to be foraging, it may also help to reduce the risk of exposure to contaminated dust.
3. Manage dandelions and other flowering weeds in and around fields, prior to planting.
4. Minimize the amount of insecticide seed treatment used.  Growers planting corn on corn with moderate to high populations of corn rootworm (CRW), should use Bt corn hybrids that have two different Bt traits to control CRW, instead of using high rate of seed treatments which are not as effective.  Get back to integrated pest management.  Evaluate your fields and determine if soil pests are present at threshold levels this spring and start thinking about whether an insecticide seed treatment is actually needed.
5.  Limit the amount of seed lubricant (ie. talc or graphite) used at planting. The current lubricants used are abrasive to the seed coat, rubbing the insecticide seed treatment off which helps to carry the contaminated dust into the air.  There has been a tendency to err on the “safe side” for planter performance, applying lubricant at the upper end of the label rate.  Follow label recommendations as the amount of lubricant needed varies by planter.  A build-up of talc on the blower exhaust indicates overuse.
6. Exhaust dust towards the center of the field.  If your planter exhausts air towards the right side, plant in a clockwise direction.  This will help direct the dust into the field rather than directing the dust onto the vegetation and water sources near the field’s edge.
7. Modifying planters with deflectors.  Deflecting exhaust air directly at or into the ground will reduce the distance the contaminated dust is able to travel.  Deflectors have yet to be tested here in North America to determine their impact both on planter performance and on efficacy to reduce dust concerns.  Research into this option is currently under development.

Following all of these measures does not guarantee that bee incidences won’t occur in 2013 but we can not afford to neglect the role that pollinators play in agriculture and society in general.  Planting time can be a frantically busy time but is important to do what we can to help protect the bees from any risks posed by agricultural practices.

Further detail on these steps can be found at: http://www.omafra.gov.on.ca/english/crops/facts/reduce-risk-pollinators.htm

In addition to our OMAF and MRA Best Management Practices, the Pest Management Regulatory Agency (PMRA) has also developed BMPs for Pollinator Protection during Corn Planting.  They can be found at: http://www.hc-sc.gc.ca/cps-spc/pubs/pest/_fact-fiche/pollinator-protection-pollinisateurs/index-eng.php

We are looking for 2 corn growers per county from the following counties: Essex, Chatham-Kent, Lambton, Middlesex, Elgin.

Grower Criteria:

1. Each grower has to have two fields of 80 acres or larger, somewhat near each other and most importantly USING LARGE NEGATIVE vacuum air planters (16 row or bigger).
2. We are aiming for conventionally or reduced tilled fields (worst case for dust movement) but are willing to go with some no-till ones too (tillage practice MUST be the same for both fields supplied by each grower).
3. Planting corn treated with neonicotinoid seed treatment (Poncho or Cruiser) and PREFER if they are planting the same hybrid from the same supplier in both fields.
4. BOTH fields NEED TO BE within about 2 km from a bee yard and perhaps the grower could direct us to who the owner is so we can discuss collecting pollen etc on some of their colonies. If they have no idea if an apiary is nearby, that is fine..we can do the searching for the bee yards and owners too.
5. Be willing to coordinate their planting plans with us (ie. contact us in advance before they plant these fields and be willing to wait for our arrival the day of, to plant the field) so that we can take measurements before, during and after planting.  It is vital that we are present during the planting so we can capture the data and samples we need for analysis.
6. Bayer will supply the new seed lubricant for one field per grower.  The grower will supply his own standard lubricant for the other field.
7. We will need regular access to both fields in the spring, early summer and again during pollination to collect soil, dust, weed and pollen samples.

Brief synopsis of the project

• We plan to take soil samples from each field for composition, moisture and residue analysis.
• We want to survey what flowering resources and pollinators are present along the fields edge weekly, before, during and after planting.  A field history for each field, including previous crops and tillage practices etc. will be gathered.
• We will be locating a beekeeper that is within 2 km of these fields that are also willing to participate, so that we can put pollen traps and dead bee traps on a few of their colonies.  We want to collect pollen to determine what the honey bees have been foraging on during the corn planting season, and count any dead bees that are present in the hives.
• The corn grower would then plant one of the two fields.  The first field would be planting using a neonicotinoid seed treatment with TALC or GRAPHITE as the lubricant.  We will be placing dust capturing devices in and outside the field at various distances while the field is being planted to determine how far the dust is traveling downwind.  We will also be taking wind measurements and capture other meteorological data at the time.  The grower would then need to clean out his planter to remove any talc or graphite dust and plant the second field using a new lubricant from Bayer.  We would again be placing dust capturing devices at various distances etc. as we have done in the first field.

Please contact me (@tracey.baute@ontario.ca or 519-674-1696) if you are a grower who fits the above criteria and are interested in participating in our study this year.  Thanks.

• Session in the lab, looking at swede midge and other easily confused insects on sticky cards with naked eye and microscope; swede midge specimens on sticky cards and in alcohol under microscope; images of damage at different plant stages; possibly some infested plants to look at and/or pull apart to look for larvae
• Instructional session on interpreting trap results and determining populations.
• Final wrap up with time for Q&A and general discussion

If you are interested in attending, please email carrie.james@ontariocanolagrowers.ca

A high level of concern was raised last spring regarding bee kills and corn planting. Many growers are asking what actions they can take to help reduce the risk of bee kills this spring during planting. We will try to clarify the situation, and give the best recommendations we can provide at this time.

In the spring of 2012, coinciding with corn planting, there were approximately 200 incidences of what was likely acute poisoning of honey bees in Ontario.  Representatives from the Ministry of Environment (MOE), Pest Management Regulatory Agency (PMRA), and OMAFRA investigated affected bee hives, taking bee samples for residue analysis by PMRA. Though final results have not been released, PMRA’s initial lab results indicate “that pesticides used on treated corn seeds may have contributed to at least some of the 2012 spring bee losses that occurred in Ontario, however, there is still additional information being collected”.  It is important to note that they have found no cases of off-label use by growers. It is also important to note that, though the analysis indicates the presence of clothianidin (active ingredient in Poncho), thiamethoxam (active ingredient in Cruiser) breaks down to metabolites that include clothianidin. Virtually all corn seed sold in Ontario is treated with some form of the insecticides in question.

Many factors may have contributed to these incidences. Environmental conditions and planting practices during the 2012 planting season may play a significant role. Unfortunately, without being present in each field at the time of planting to collect data, there may never be conclusive evidence as to route(s) of exposure to bees. However, results indicate that honey bees were somehow exposed to corn seed insecticides. So how can a bee come into contact with a seed insecticide during planting?

One of the more likely routes is dust.  Research from Purdue University and other jurisdictions in Europe have found evidence that dust coming from the exhaust of high pressure air-assisted corn planters contained particles of neonicotinoid (eg. Poncho or Cruiser) seed insecticides.  Many factors can contribute to the contamination of the dust including abrasion of the seed from the planter lubricant (eg. talc), quality and formulation of the polymer seed coating (sticker), and rough handling of the seed bags causing chaffing of the seed coat.  Planting on dry, windy days may also help to carry the “fugitive dust” greater distances.  Bees can come into contact with the contaminated dust while flying across the field during planting or from the dust settling on water sources or nearby flowers that they are foraging on.

What can corn producers do to help reduce the risk of bee kills when planting? The following are actions that should help reduce the production of contaminated dust during planting, and consequently (hopefully) reduce the exposure of bees to this dust.  There is no guarantee that these actions will prevent bee kills from happening during planting.  Many of these are best management practices that growers should be following anyway, given they are applying pesticides when planting treated seed.

1. Strengthen communication with local beekeepers.  Honey bees can forage up to 5km from their hives.  Take an active role in finding out where the nearest hives are to your fields and let the local beekeepers know when you plan to plant.  There may be steps that they can take to protect their hives during planting. Contact information for the local beekeepers’ association in your area can be found on the Ontario Beekeepers’ Association website at: http://www.ontariobee.com/community/local-beekeepers-associations
2. Time of planting. Keep in mind that during dry spring conditions, dust will travel further on windy days.  If there is an opportunity to plant in the early morning or evening on windy days, when bees are less likely to be foraging, it may also help to reduce the risk of exposure.
3. Manage dandelions and other flowering weeds in and around fields, prior to planting. The warm March, followed by a very cold April of 2012 may have resulted in dandelions being the predominate flowering plant for bees to forage on during corn planting. Managing flowering weeds in and along field perimeters prior to planting may help to reduce the likelihood of bees foraging around your field at the time of planting.
4. Minimize the amount of insecticide seed treatment used.  Growers planting corn on corn with moderate to high populations of corn rootworm should consider planting a Bt corn rootworm hybrid. Transgenic control has been proven to be more effective than using a high rate of seed insecticide. In addition, not every grower in the province has soil insect pest problems.  It is time to get back to integrated pest management.  Evaluate your fields and determine if soil pests are present at threshold levels. Even if they were in the past, it doesn’t mean they are now, especially if insecticide seed treatments have been used in the same field over multiple years.  If the soil pests are not at threshold and impacting yield, a seed insecticide is not necessary.  Most companies can accommodate orders for non-insecticide treated seed, as long as the orders are done well in advance.   Test non-insecticide treated seed to see how they do on your farm.  For information on how to monitor for soil insects and determine thresholds, refer to the Soil Insects and Pests section of the OMAFRA Publication 811, Agronomy Guide for Field Crops at: http://www.omafra.gov.on.ca/english/crops/pub811/13general.htm#soilpests
5. Limit the amount of seed lubricant (eg. Talc) used at planting. The amount of lubricant needed varies by planter.  There has been a tendency to err on the “safe side” for planter performance, and apply at the upper end of the label rate.  Experience from some growers would suggest that in low humidity situations, little to no talc is required.  Follow label recommendations.  A build-up of talc on the blower exhaust indicates overuse.  Take precautions to reduce the risk of inhaling talc, which can have serious health effects.  Fortunately, there are promising new lubricants being developed that could greatly reduce the amount of dust produced.
6. Exhaust dust towards the center of the field.  When planting the outside rounds along the perimeter of the field, blow the air in.  If your planter exhausts air towards the right side, plant in a clockwise direction.  This will help direct the dust into the field rather than directing the dust onto the vegetation and water sources near the field’s edge.
   
7. Modifying planters with deflectors.  Deflecting exhaust air directly at or into the ground will reduce the distance the contaminated dust is able to travel.  Deflectors have been mandated in parts of Europe to reduce dust implications.  In North America, deflectors need to be tested for their impact both on planter performance and on efficacy to reduce dust concerns.  Stay tuned.

Again, following all of these recommendations does not guarantee that there will not be future bee kill incidences at planting.  These are the best suggestions we can offer based on the information available to date.  We will continue to modify these recommendations as more information is made available, and research and technology is developed to address the issue.  Updates will be provided on the Field Crop News site at: http://fieldcropnews.com/

Note: Any suspect bee kill incident taking place during spring planting in Ontario in 2013, should be reported to Linda McIntosh, Regional Manager – Pesticide Compliance Program – Health Canada at:

Linda McIntosh
Regional Manager
Pesticide Compliance Program – Health Canada
255 Woodlawn Rd W, Unit 109
Guelph ON, N1H 8J1
phone: 519-826-2895

Head of Winter Cutworm Larva (Photo Credit: Chris DiFonzo, MSU)

A winter wheat field near Owen Sound has 4 to 5 acres of “missing plants”, cut off at the soil level.  Not many insects could do that kind of damage this time of year.  It sounds like a case of winter cutworm.  It was to the day, 4 years ago when I wrote a CropPest article about this pest.  A very common insect that occasionally decides to munch on our crops.  And this case can not be the only field in the area with feeding damage.  I suspect there are more wheat and hay fields in the same situation.  The problem with this pest is that it is very cold tolerant, surviving sub-freezing temperatures and can feed now on these sunny fall days and even under snow during the winter months.

Winter Cutworm Larva from Above (Photo credit: Chris DiFonzo, MSU)

As mentioned in the past article, I recommend that hay and winter wheat fields are accessed at least once before there is substantial snow cover.  Look for bare patches in fields and larvae that may be present or moving in from neighbouring fields and ditches.

Not much can be done now to control the larvae.  It is too cold to apply foliar insecticides but at least you will be aware of the situation and come spring, be able to assess any further damage they may have done over the winter.

Interestingly, this is one of the moths (Large yellow underwing moth) that tends to get caught in our western bean cutworm traps.  Perhaps it is time for us to be keeping track of their numbers too and alerting growers to the potential risk of fall/winter damage.

There are quite few calls coming in from people who are finding either Japanese beetles or redheaded flea beetles in their soybeans, feeding on the leaves.  Though the feeding might be alarming at first, rarely does this defoliation actually reach threshold levels.  Most of the defoliation happens at the top of the plant which is why it is easy to overestimate what damage is taking place.  Soybeans are great for compensating for the defoliation.  Leaves under the ones with holes grow larger to take advantage of the extra sunlight penetrating the canopy thanks to those holes.

Here is an article on assessing defoliation and what the defoliation thresholds are.  It also includes pictures of most of the leaf feeding culprits.

Article: Soybean Defoliators and Thresholds

Figure 1. Bird Cherry Oat Aphids. Note the red patches around the tailpipes of the aphid. Photo Credit: J. Obermeyer, Purdue University; Figure 2. Corn Leaf Aphids. Photo Credit: University of Illinois Extension

On-farm trials done in Ontario have not found an economic benefit to spraying aphids, though if populations reach an average of 12-15 aphids per plant prior to heading, an insecticide application may be required, though again, this is a rare event in Ontario.  Make sure to scout throughout the field when determining the average, since aphids can start in patches and population levels can be overestimated if scouting is only done in these patches.  After heading, the threshold is 50 aphids per plant.  Malathion 500, Pro Malathion 50, Cygon 480 and Cygon 480 EC are registered for aphids in cereals.  Pre-harvest intervals for Malation is 7 days and 21 days for Cygon. Consult product labels for rates and precautions. Beneficial insects do a relatively good job of controlling aphid populations so consideration should be given to how the beneficial insects are dealing with the aphids before applying an insecticide since the registered insecticides will harm the beneficial insects as well.  If the numbers are at threshold however, an insecticide treatment may be advisable.

The main concern with cereal aphids is that they vector barley yellow dwarf, especially if volunteer wheat was present in the field in the fall when the aphids arrived.  They can pick up the virus from unhealthy plants and vector it into the healthy crop.  Applying an insecticide will not reduce the incidence of barely yellow dwarf.

For more information, refer to the Agronomy Guide for Field Crops, OMAFRA Publication 811 at: http://www.omafra.gov.on.ca/english/crops/pub811/p811toc6.htm

Beneficial insects that feed on aphids

Lacewing egg

Lacewing larvae

Lacewing adult

Flower bug

Lady bird beetle

Photo Credits: publication 310, Integrated Pest Management for Apples

The Canadian Corn Refuge Hybrid Selector is a web-based tool that has been developed through collaboration of the Canadian Corn Pest Coalition, the Ontario Corn Committee, and the Canadian Seed Trade Association to provide all the information needed to follow up-to-date insect resistance management (IRM) requirements for all currently available Bt corn hybrids in Ontario.

Refuge Selector

Simply select the Bt hybrid or trait being planted and the field size and the Refuge Selector will provide a list of eligible refuge hybrids, the refuge size, placement and treatment options along with herbicide tolerance information.  The Refuge Selector can be accessed through the Canadian Corn Pest Coalition website http://www.cornpest.ca/ or through http://www.refugeselector.ca/.  It’s an excellent tool to help you place your 2012 seed order.

Though we know there were hot spots this year, including Bothwell to Strathroy and south of Tillsonburg, we encourage all corn producers to be scouting for ear damage over the next month.  Scouting will identify additional areas that had decent WBC pressure and are at risk of higher overwintering populations and therefore infestations again next year.  Scouting will also help in deciding whether to harvest the crop earlier, or to segregate grain from those fields to reduce risk of ear rot and vomitoxins.

Fields in the Bothwell area are seeing significant ear damage already.  Even fields planted to Herculex or SmartStax Bt corn that contain Cry1F are seeing greater amounts of damage than growers were expecting.  These Bt hybrids provide only approximately 70 to 80% control, so under heavier pressure, the damage can be significant.

Focus on later planted fields first.  Scout random areas of each field.  Look at 10 consecutive ears in a row.  You might see frass at the ear tip or a hole along the side of the husk where the larva entered. Peel back the husk and determine if larvae are present and make note of how extensive the feeding damage is.  Birds diving into fields is also a good indication that WBC is present and unfortunately they will also contribute to the ear damage.  Once the larvae reach the 6th and last instar, they drop to the soil and tunnel down deep to overwinter there.  If larvae are nowhere to be found in the field, it is a good indication that they have already started to get ready to overwinter.

Hopefully we experience a warm and reasonably dry fall to help mature the crop quickly and avoid ideal weather conditions that promote further ear rot development.