Just wrote an article and completed the map of the distribution of western bean cutworm in the Great Lakes Region. Check it out in the latest CropPest Newsletter at:
http://www.omafra.gov.on.ca/english/crops/field/news/croppest/2009/18cpo09a3.htm
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More reports of WBC damage are coming in. Here is an updated list of sites with damage and or larvae found in Ontario:
Chatham- Kent (Dover Centre, Bothwell)
Lambton (Petrolia)
Middlesex (Wardsville, Appin, Glencoe)
Elgin (Rodney)
Huron (Blyth, Clinton, Exeter, Dashwood, Holmesville, Belgrave)
Bruce (Walkerton, Kincardine)
Simcoe (Alliston, Barrie, Stayner)
Durham (Kinsale, Lindsay, Brooklin)
Victoria (Dunsford)
Peterborough (Millbrook)
Dundas (Chesterville)
I will be attending a meeting this week with my US counterparts where we will be discussing what each state/province has observed with regards to WBC and soybean aphids. I will give an update next week on any new information from the meeting.
Sorry…It’s been a few weeks since my last blog but I finally went on holidays. I’m back and want to give you an update. While away, more reports were coming in of western bean cutworm damage being found in Ontario. Others are asking how to scout for the damage this fall so that they can determine if they have WBC. So here is an update:
Counties (nearest town) reporting larvae and/or damage in 2009 include:
Chatham- Kent (Dover Centre)
Lambton (Petrolia)
Middlesex (Wardsville, Appin)
Elgin (Rodney)
Huron (Blyth, Clinton)
Simcoe (Alliston, Barrie)
Eastern Ontario - Dundas (Chesterville)
Anyone who finds damage/larvae in their field, please report it to me either via this blog or through email so that I can continue to keep track.
How to scout for WBC damage this fall: WBC damage will not necessarily be in one specific area of the field. Wander through the field looking for any signs of frass at the ear tips. Look for any signs of external entry holes from the sides of the husk, though WBC do not always enter from the side of the ear. Signs of bird damage can also indicate that there was something in the ear that the bird went after. Though bird damage does not confirm that WBC was in the ear. The birds could be going after picnic beetles, corn borer or corn rootworm adults too. I have also had the odd hybrid that didn’t have a tightly closed husk at the ear tip and when there were signs of less silk or there was frass on the silk, I’d open that husk to investigate. Otherwise, just peel back random husks throughout the field if no external signs of damage exist. Once you have found an ear with damage and or larvae, investigate the plants around that one. Check in that row and the plants in the rows directly adjacent to the initial plant with damage. Odds are there will be more. These larvae spread from their original egg masses and can crawl 12 feet down the row and 10 feet across. So many neighbouring plants can be infested by just one eggmass.
If a WBC larvae is not present in the ear that has damage, we can not fully confirm that the damage was caused by WBC as it could also have been from ECB or corn earworm..though WBC does tend to be the most destructive feeder.
Here is a scouting video through Purdue University that helps explain what I’ve talked about: http://extension.entm.purdue.edu/pestcrop/2009/issue21/index.html#westernWhat do you do if you find damage? First, report the location of the damage to me. Then keep an eye on the quality of this site before harvest. If ear rot starts to set in because of the damage caused by WBC, plan to harvest this field as early as possible. Additional precautions/actions that should be taken to reduce the impact of ear rot can be found in the Agronomy Guide, OMAFRA Publication 811 at: http://www.omafra.gov.on.ca/english/crops/pub811/14corn.htm
That is all the bad news I have for today 
Pictures are also available in my previous blogs and on the WBC Trap Network website at: http://www.cornpest.ca/default/index.cfm/wbc-trap-network/trapping-workshop/
We visited the Newbury WBC site last week and it was concerning to see so many plants infested with WBC larvae. There were no external entry holes from the outside of the ear which could fool those who think the ears are clean. Pay extra attention to those ears that are slightly opened at the ear tip (husk not tightly closed) and if the silks look thinned. Once ears are peeled open, look for signs of frass (larvae excrement). Neighbouring plants are also likely to have larvae too.
More reports were coming in late last week from reps who were out checking their trials and finding WBC. So far, WBC larvae have been found in corn in Dover Center (by Shawn Winter of Maizex) and near Strathroy (by Nick Stokman). Also, Joe Tomecek reported finding WBC in dry beans near Kent Bridge.
Please keep checking fields and sending me your damage reports. There is nothing we can do this year about this injury (and none so far have been at economic levels) but the more damage sitings we know of this year, the more knowledge we gain about the distribution and impact of this pest in Ontario. It will also inform us of any potential overwintering sites and potential problem regions for next year.
My summer students are going to be frustrated when they find this out, especially with all of the scouting they have done looking for WBC egg masses and larvae and finding nothing to show for it. But today Adam Pfeffer of Monsanto brought in the first WBC larvae found here in Ontario. The larvae was from a corn field in Rodney Ontario. This tells us that there are probably other sites with some larvae in them as well, so I do encourage you to be out scouting your fields too. Larvae would most likely be in the ear of the corn. But we are also still catching moths in our traps so some egg laying could still be taking place.
Purdue University put a WBC scouting video within their newsletter this week which helps explain how to look for larvae in the corn ear: http://extension.entm.purdue.edu/pestcrop/2009/issue21/index.html
And Ron Hammond from Ohio State University put together a video from our trip to visit Chris DiFonzo from Michigan State University in one of her heavily infested corn field last year: http://www.youtube.com/watch?v=u5EsPWySxEI
If you do find ear feeding, larvae or egg masses, please let me know!
Some counties in Michigan have been given the recommendation to spray their dry beans due to the high moth counts and observations of pod feeding at some locations. Montcalm County (central Michigan) in particular is at the highest risk with some trap sites capturing over 400-500 moths in the last few weeks. Isabella, Gratiot and Mecosta counties are also considered at risk. Current Michigan WBC Trap Map: http://www.msuent.com/files/WBCmapAug15.pdf
Thankfully Ontario has not yet experienced these kind of levels yet. Current Ontario WBC Trap Map: http://www.cornpest.ca/?LinkServID=848D2ECA-188B-3AFA-083F4B11E7B95388&showMeta=0
Only one trap site near Appin has accumulated more than 50 moths so far in Ontario. Others have been ranging from no catches to about 30 moths so far. We have been scouting for egg masses and feeding damage at most sites that have captured moths but have not found anything yet in corn or dry beans. However, given what Michigan is dealing with this year, I don’t think we have many more growing seasons to go before we are see levels high enough that management will be needed in at least some fields.
SPIDERMITES: I have a sneaking suspicion that spidermites are making their way into those fields that haven’t had rain in a while. We have had situations in the past where not only have they popped up in soybeans and were being disregarded as “drought stress” symptoms but also in seed corn, especially around or just after wheat has been harvested in the area. Be particularly careful in watching those fields that may have had a pyrethroid used recently for any other insect issues. Pyrethroids do not work on spidermites and can actually cause mite populations to flare up. For more info on spidermites and scouting, refer to: http://www.omafra.gov.on.ca/english/crops/pub811/13soybean.htm#spider
SOYBEAN APHIDS: As suspected, some fields are noticing a drastic decline in numbers, while others have seen a drastic increase. A significant soybean aphid flight took place this week (as captured by our suction traps) and some winged aphids left the early planted fields they started in this summer and have moved to later planted fields either nearby or in other regions entirely. But we also may have received aphids from neighbouring states and provinces so fields should be checked soon to figure out if you were one of the lucky ones or not.
WESTERN BEAN CUTWORM: We experienced an increase in moth captures this week, indicating that this is a good time to start scouting for egg masses, especially at trap locations that have been catching moths into the double digits. Since corn is still barely tasseling, the moths will prefer to lay their eggs in corn still. Trap capture maps for this week are at: http://www.cornpest.ca/default/index.cfm/wbc-trap-network/weekly-maps-of-wbc-trap-catches/
Information on how to scout for egg masses and larval activity can be found at: http://www.cornpest.ca/?LinkServID=3FD7CC42-65B8-8CF0-A092D60341F09626&showMeta=0 Make sure to click on the speaker notes at the top left of each slide for more detailed information.
Also here is an infosheet on WBC in corn: http://www.cornpest.ca/?LinkServID=D23DD4EE-188B-3AFA-0809F13CA830D6F4&showMeta=0
Have a Fantastic Long Weekend Everyone!
First off, I apologize for not updating the blog for the last little while. I’ve been busy with setting up the SouthWest Diagnostic Days and just ran out of time. But let me catch you up on a few things that have taken place but I am also hoping that others who have been out in fields more than I this week can send their comments in on what they are seeing.
SOYBEAN APHIDS - Looks like we have a few fields out there that are reaching above the threshold of 250 aphids per plant and increasing, present on 80% of the plants as they enter the R1 stage soys, particularly in Eastern Ontario (Stomont, Dundas and Glengarry counties) and Southern Quebec. Spraying has been taking place over the last week in Eastern Ontario. Now that most of the soybeans are in or are about to hit R1 across the province, scouting should be done at least once a week to assess what the aphids and natural enemies are doing. Many of the fields are in good shape with timely rains and lots of natural enemies but others are starting to feel the stress from lack of rain and fluctuating temps.
WESTERN BEAN CUTWORM - A few moths have now been found in Ontario through our trapping system. So far moths have been caught in Essex and Chatham Kent Counties (only 1 moth in each of 4 traps). Any trap participants out there are asked to send in their information in on a timely basis so that we can continue to report and map these captures. We will keep you informed on any increasing levels of captures and “areas of concern” that may need to be scouted for egg masses and potential damage.
That’s all for today! Please send in your comments on what you are seeing out there so that we can share that information.
The first report of spraying for armyworm in sweet corn in Essex County came in today. We are not sure how heavy of infestation to expect in other fields but wheat and newly emerging corn fields should be scouted in Essex, Chatham-Kent, Lambton, Elgin and Middlesex counties asap. Armyworm reports from Essex tend to give us a few days heads-up to catch any infestations in the neighbouring counties. But other counties in southwestern Ontario should be scouted in the next 7 days to 10 days to determine if armyworm is present there.
A CropPest Newsletter article will go out later this week with details on scouting and management strategies. You can also find information in the Agronomy Guide for Field Crops and past CropPest articles (links provided below)
http://www.omafra.gov.on.ca/english/crops/pub811/3taw.htm
http://www.omafra.gov.on.ca/english/crops/field/news/croppest/2008/05cpo08.htm
Thanks for the Heads-up Bob Buis! Bob reports that he has seen a field with 5% of the plants cut by cutworm in the Lighthouse Cove (Tilbury) area. Cutting indicates that the cutworm larvae are bigger and more mature and may be difficult to control. Now that corn fields are emerging, they need to be scouted every 5 days for leaf feeding and cutting. Don’t assume that insecticide seed treatments or Bt corn will control them since these products typically only work well on the younger, smaller larvae. This year’s difficult spring has allowed cutworm larvae to feed and grow on the weeds that didn’t get an early burn down while waiting for the corn to come up. Refer to the OMAFRA Agronomy Guide for thresholds http://www.omafra.gov.on.ca/english/crops/pub811/3bcutw.htm If management is required, spray late in the evening when the larvae are actively feeding.
Happy Scouting and Don’t Forget your Rubber Boots!
