Baute Bug Blog

Hi Everyone. 

I realize that I haven’t been blogging lately but I didn’t want to bog you down with frivolous things during busy times.  That said, I did want to take the time to wish you all a wonderful and safe Holiday.   And I wish you nothing but the best for 2010. 

If you have a bit of time during the holidays to surf the web, here are some interesting links for you to check out.

I get asked a lot about where to find great Insect Calendars.  Here are a few sources that I recommend:  

Entomological Society of America’s 2010 Calendar    and        Insect Calendars on Calendars.com

And for Insect Posters:

University of Guelph’s Insect Collection Posters

I am often asked where to find more detailed, higher level Insect Publications.  

Dr Steve Marshall from the University of Guelph has published a 736 page book filled with photos and short details on each insect.  It might be too high level for some but it is a great resource to flip through to try to find out which insect you recently caught to ID.    Insects: Their Natural History and Diversity: With a Photographic Guide to Insects of Eastern North America

I refer to these next books all the time for field crop insect pests.  They are more expense as non-members of the society but they are worth it.  Entomological Society of America’s Insect Pest Handbooks.  I have many of these in my office so if you would like to see a copy before buying it, feel free to come and see me.

These are some of the most spectacular Insect/Arthropod photos out there:

 Igor Siwanowicz               Thomas Shahan          U of Guelph’s own Dave Cheung

And finally, if any of you have had a longer conversation with me, Ted.com usually comes up.  I am a huge fan of the talks on this site as they are some of the most inspirational, cutting edge and thought provoking discussions in the world.  I highly recommend that take the time to check out many of the talks on this site.  If you are an IT/gadgets freak you will be blown away with some of the near future technology presented on this site.  There have been a few interesting ones on insects too including:

Deborah Gordon Digs Ants   and   Dennis vanEngelsdorp’s Plea for Bees

Enjoy!

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.

The current threshold of 250 aphids per plant and increasing should be followed to the end of the R5 stage of soybeans. 

The R6 stage aka “Full Seed” has been reached when the upper 4 pods of the plants are full of plump green seeds.  Past research has indicated that at least 1000 aphids per plant are required before there is a yield response.  This would only apply for the very start of the R6 stage.  Once the plants reach the middle to end of R6,  the plants no longer respond as they are shutting down for harvest.  Also you need to worry about the preharvest intervals of the foliar insecticides registered which are 21 days to harvest for Matador or Silencer and 30 days to harvest for Cygon or Lagon.

 The majority of the soybeans we scouted this week were in the R4 stage.  So unfortunately we have a few more weeks of scouting to do before we can walk away and be done with the aphids.

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!

A lot of calls are coming in this week from growers and reps who have fields that are hovering around the 250 aphids per plant range.  With the poor weather and wheat harvest some are anxious to make the call if they need to spray.  In fact, there are some rumours out there that some are spraying before the field reaches 250 aphids per plant.  I stongly DISCOURAGE this as I have witnessed many times that this does not save you a spray or your time but in fact increases the chances that you will need to spray again in the next 10 days or so because of the natural enemies that were making an effort were instead killed off, leaving the aphids that survived to live well and prosper.

The best way to increase your chances of only having to spray once is to spray well within the threshold, when you have been able to assess that the aphids are definetly on the increase past 250 per plant.  

Here are my best recommendations for the current situation:

1)  In regions where the fields are quite dry and the crop is appearing stressed, plan to spray just above 250 aphids per plant, after you have confidently determined that the aphid population is actually on the increase.  This indicates that the natural enemies are not keeping up and are no longer valuable enough for you to save.

2) In regions where there have been some timely rains and the crop is not stressed, plan to spray when the aphids start to reach around 400-500 aphids per plant.  The economic injury level (when the cost of spray is equal to the cost of control) is around 600-700 aphids per plant.  In a healthy crop you can be a bit more patient and wait to see if the natural enemies kick it in gear and lower the aphid population.  But experience has shown me that once you start to crack the 400-500 aphids per plant mark, there is less of a chance that there will be enough natural enemies and time for them to keep the aphids from reaching the economic injury level.

And keep an eye out for SPIDERMITES, especially in the regions that have not had these rains.  Wheat harvest is starting and spidermites will be moving into soybean fields.  Timely rains help manage them but not every field has had these rains. 

Please let us all know if you are starting to see spidermite injury in your area!

This is a ladybeetle larvae.  They can be black or a dull grey/purple with orange or  yellow markings.  If they are shaped like an alligator, they are a ladybeetle larvae. It will be an adult ladybeetle soon.  Both the larvae and adults feed on aphids.

The black velvet coloured aphid on the right is a parasitized soybean aphid.  It is dead because a tiny wasp has laid its egg inside the aphid and the young wasp has eaten the aphid from the inside.  The adult wasp will emerge from the aphid soon to parasitize other aphids.

 The white flakes in this picture are cast skins of the aphid.  They are NOT dead aphids.  Aphids need to shed their skin to grow so they leave behind what looks like dandriff on the plants.  Do not use these to count or determine if the aphids are reaching threshold or are dying.  Only count the aphids that are Mountain Dew coloured.

This is a syrphid fly larvae.  It is also a natural enemy.  It is a blind maggot that crawls around the leaf until it bumps into an aphid and then eats it.

These are just some examples of the natural enemies that may be busy at work in your fields.  For more information on these and soybean aphid management, here is a link to the Canadian Soybean Aphid Scouting Cards: http://www.soybean.on.ca/aphidinfo/uploads/soybean_aphid_scouting_card__english.pdf

Now that we are getting into the R1 (beginning bloom) stage of soybeans, we have a bunch of research to do on soybean aphids including trying different combinations of water volume, pressure and nozzle configurations and testing new novel insecticides for future registrations.  But we need sites.  So anyone that finds soybean fields  (>25 acres) with aphids at or above 250 aphids per plant within approximately 100 km radius around London please contact me.  We’d like to set up some plots in up to 11 fields and can compensate growers for the space we take up.  With a little luck and help locating good aphid sites, we can work at adding more key elements to soybean aphid management toolbox.