Baute Bug Blog

Gaps in the stand are starting to show this week.  Aside from the typical culprits, moist soils can promote the less often accused.

Millipedes are typically a beneficial arthropod that breaks down crop debris and decaying plant material.  However, in the last few years, we’ve been seeing more direct feeding by them.  What is happening?  We have been planting earlier and earlier.  If the weather turns cool and wet, seeds that have sat in the ground for a bit, swell up but are slow to emerge, making for tasty treats for millipedes.  Corn is usually the target crop since it is the first to be planted but reports of soybean seed being fed on by millipedes have also come in this year.  Unfortunately insecticide seed treatments do not control them.  Warmer weather that helps get the crop up and out of the ground is really the only way to avoid this.

Slug feeding is evident this week.  This moist weather has brought them out of hiding.  Fields with decent amounts of crop debris harbour these pests, giving them a moist home to live in.  No till soybeans and spring canola are most at risk.  Though corn is also a host, it can usually grow out of the injury, as long as slug populations are not extreme. No insecticides are effective on slugs so this pest requires cultural control. Tillage is best, but for dedicated no tillers, using any device that can help to remove residue directly around the seed bed may reduce slug damage.  In some cases, it may be too late to take action this spring but make note of fields with slug problems and plan to take action this fall once the crop is off.

One additional note, bean leaf beetles have started to enter soybean fields.  In the fields I’ve been scouting, some plants were actually clipped off right at the base while trying to emerge.  Others had the classic round holes in the leaves.  Fields planted without Cruiser seed treatment should be scouted to ensure threshold is not reached.  16 beetles per foot of row during VC to V2 requires control or if clipping is found.

Thanks to Nick Zwambag for commenting on here that they are seeing cabbage seedpod weevil activity in winter canola near thamesville earlier this week.  But with this weather, little can be done about it and fortunately the cool temps should slow them down a bit.   Scout once this front goes through and see what infestations are like then.

Bean leaf beetles are not quite yet.  We’ve been sweeping in alfalfa fields and have not captured any.  We tend to see them emerging around this time so I expect if things warm up a bit, they will be making their way into alfalfa or newly emerging soybeans (if the soys escaped the frost).

These storms are also apt to be carrying in black cutworm and true armyworm moths.  States just to the south of us are reporting black cutworm flights and feeding activity.  Fields that had a decent weed mat this spring should be scouted.  There have been fewer armyworm reports but given the advanced wheat crop, those fields are going to look mighty appealing to the mother moths flying by.

And finally, Ohio is still reporting quite a lot of cereal leaf beetle activity, though I haven’t heard or found any yet here.  I do recommend that once this rain passes, we get out and look for armyworm and cereal leaf beetles.  This heavy moisture might be good for initiating entomopathogens but it needs to be a bit warmer for the fungus to get established.

Let’s hope we see the sunshine soon!

There are a few guys out there thinking that with the cooler nights, SOYBEAN APHIDS will be leaving their fields so they don’t need to spray those fields that recently reached threshold.  If aphids are staying at threshold levels 3 or 4 days after the initial assessment, you still need to spray.  Only those fields that are dropping in numbers or have reached into the R6 stage and are no where close to threshold can be considered safe from having to be sprayed for aphids.  The cool night temps do not guarantee the aphids will leave to look for buckthorn yet.  Triggers from plant quality may also determine whether they stay or go elsewhere.

HOWEVER other insects are starting to be a problem.  IP and seed fields need tending to still.  BEAN LEAF BEETLE adults are showing up in high numbers at a few of our sites in both Lambton and Elgin Counties.  Fields in other counties could also be at risk.  Scout fields to determine beetle presence and look at pods for feeding.  I like to pluck about 50 pods randomly in the field, grabbing pods from the top 3rd of the plant without taking the smallest/youngest ones.  If 10% of the pods collected (or in this case 5 pods) have feeding scars and holes on the surface, AND the beetles are still active in the field, a spray is required in IP or seed fields if the crop is not reached the middle of R6.  Preharvest intervals come into play if you get any deeper into the R6 stage of soys.  Look for clipped pods on the ground as well as this should also be included in your assessment.  If significant clipping is taking place and beetles are still active in the field, spray is required.

STINK BUGS  have also made an appearance at threshold levels in a field in Chatham Kent.  Very high numbers were reported by Joe Tomecek  and after some discussion it was obvious the field needed to be sprayed.  Again, only IP and seed soybean fields are at risk, as stink bugs impact quality by piercing the soybean pod, scaring the seed itself.  Control may be warranted in IP food grade and seed soybeans if an average of one stink bug per foot of row or 0.2 bugs per sweep are found during the late R5/early R6 stage of soybeans.

Okay..it is a busy week on the insect front.  Sorry..two posts in one day but I want to get the message out!

Bean leaf beetle adults are active in emerging soybean fields.  We are starting to see feeding damage in several fields in the southwestern counties.  These beetles have been waiting a while for soybeans to come up.  Fields not planted with Cruiser in areas that have been known to have overwintering adults (up to S. Huron and Wellington Counties) will need to be scouted to determine infestation levels.  For more information on bean leaf beetle scouting and thresholds, here are some helpful resources:

http://www.omafra.gov.on.ca/english/crops/pub811/4blb.htm

http://www.omafra.gov.on.ca/english/crops/pub812/3blb.htm

Cereal leaf beetles have also reached threshold in fields in the Aylmer and Delhi areas, which tells me that there could be more hot spots in that region (or others) that are being missed .  Scout wheat fields to see if any larvae or adults are present.  I realized the other day, a good way to describe the larvae is to look for a very dense muddy drop of water on the leaf.  If you look closer, it is probably cereal leaf beetle.

Since there is not much crop up yet to spot feeding injury on, there really is not much happening yet on the insect front.  However, anyone that did push planting and planted into too wet or cool soils, or deep planted may start seeing some issues when the crops starts to emerge.  Millipedes and slugs in particular could be a problem this year given how wet it was and neither are controlled by the insecticide seed treatments that everyone is using and expecting to control all things with.  It is really important to get the message out to stop planting too early when the soil is not fit and/or too deep as it is just giving the seed to these pests.  And these insecticide seed treatments do not control everything out there.

Bean leaf beetles adults are out now.  Not sure what kind of populations we are going to see this year.  But with overall planting being on the later side, this could put us at risk for an extended pod feeding period into mid September, as these critters like to feed on late planted soys since the pods would still be green and succulent then.  But we will see.

And as for soybean aphids..well I didn’t find any on the buckthorn I scout every year.  And there have been very few reports anywhere in the states either.   It could just be that we are not looking in the right places, as it doesn’t take much of a colony to give us a decent population on soybeans each year.  But it is really strange that we haven’t found something yet, given the record aphid catches we experienced in the fall in the suction traps.  I’m not willing to say that aphids won’t be a problem this year though.  They’ve taught me to never write them off or claim a “No Aphid Year”.

As always, if you are seeing anything out there..let me know!