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The Cropwalker - Volume 4 Issue 20

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Crop Conditions

Weather remarkably warm and sunny. Some fields in the Sarnia area according to Ryan Benjamins CCA ON got up to 1” but some areas just received a light shower., and many areas nothing In the Niagara area Susan Gowan says no rain and big cracks in the ground. Most of the province is dry. My daughter Kate is a water resource engineer at the Grand River CA, so she monitors water and rain etc. She tells me that the dry May was predicted, but the meteorologists she follows are predicting normal rainfall in June and July. She said that Lake Erie is down a foot from last year, but still above normal levels. Lake Huon is still a bit above average level. Winter wheat Ryan Benjamins CCA in Sarnia area says” I can’t believe how early the wheat is. T3 timing here this week. I’ve never had T3 timing before June 1”. For the rest of the province, flag leaf is out and now is when you need to protect the flag leaf. Our consortium of agronomists is recommending Headline AMP or Stratego Pro, or Cerefit, or Trivapro depending on your retailer and which companies’ programs you are already tied into. Watch for Cereal Leaf Beetle (CLB) in the traditional areas and a bit more. This pest spreads a bit more every year. Threshold is 1 larva per stem. If you walk through a wheat field checking for army worm and T3 timing and your plants turn blackish, it is CLB.  Corn is all planted and earliest emerging without issue. We are doing another planting update and will send the results this week. Soybean planting is 80-100% done across the province. Forages First cut is well underway. Yields are good, better than expected. If not planning on cutting for a week, check for weevil. There are a number of fields being sprayed in the Niagara area and at least one in the Sunderland area. New seedings are at first trifoliate and should be sprayed now. Reminder that there is less crop injury to seedling Alfalfa spraying Embutox/Cobutox/2,4-DB at the start of the labelled 1-4 trifoliate stage, than later Keep water at 20 gallons and do not spray in the middles of the day if above 25 or will get above 25 in the first few hours after spraying. Spring cereals should have weed control applied or lined up to be applied by now. If not check last week’s Volume 4 Issue 19 May 19 2021 spring cereal herbicide quick review.


Weed alert

Recent dry weather means most pre herbicides will not be working. Check all fields. For Roundup Ready crops consider an early application to get the first flush. You may need at least one more application. These weeds will be much easier to kill now than later. For IP soybeans, check and make options.

Fungicides for fusarium control

With flag leaf fully extended it will be 2-3 weeks to Fusarium Head Blight (FHB) timing. Typically, you can expect 2-3 weeks of leaf disease protection with a fungicide. The strobi group of fungicides prevent spores from germinating. They do a great job giving protection from stripe rust. You cannot spray a strobi once the head appears. That is when you switch to a triazole (Caramba, Miravis Ace, or Prosaro XTR).

Checking corn and soybean emergence

Great year to evaluate your planting and equipment. Hopefully emergence is even and you are satisfied. If considering replanting corn, my guidelines is you leave 18,000 corn plants, replant if 12,000 and in between you have to factor a bunch of things such as acres affected, can you remove the first stand with another herbicide, do you have enough moisture to get a new stand. For soybeans, you only need 100,000 good plants to get maximum yield. If you do decide to touch up, use the same variety and consider using close to your original seeding rate (minimum 120,000 seeds). For areas where soybean seed is only ½” deep consider replanting now if you can get close to moisture

Figure 1 - Expected Yield by Corn Population

Corn Yield Loss Due to Uneven Emergence

There are some misconceptions. If corn emerges at different times in different areas of a field, like the sandy area emerging sooner than the heavy area, this is not a yield reducer. It is when individual plants in a row, side by side, emerging at different times is a yield loss. Research shows that individual plants that emerge 10 days late will have an 8% yield loss. Individual plants that emerge 21 days later have a 10-20% yield loss. If you have plants that are 2 leaves different, there will be a minimal yield loss. Plants that are 4 leaves behind fall into the 10-20% loss. If 20% of corn plants are 4 leaves behind the rest this could be 5-10% overall yield loss. If 20% of the plants are 3 weeks delayed emerging you should find out why. If yield potential from original stand is higher than replant yield potential, you should not replant. For a more detailed decision maker go to http://gocorn.net/v2006/Planting/articles/Ontario%20Corn%20Replant%20Decision%20Aid%201.8.xls

Yields with Reduced Soybean Populations

It is amazing how well low population stands can yield. This research was done by hand-thinning a good stand. Survivor plants were healthy. In real (your) fields, stands are reduced and remaining plants are not always healthy. Consider these yields as best case. (Consider reducing your yield expectation by 20% with the populations in the table). Check your population from previous years and compare to final yield. You may be amazed as to how good a yield you had another year with a low population. Inter-planting corn into an existing corn field seldom works. Inter-planting soybeans into a stand works. If replanting, consider staying with the original variety. Consider dropping 120,000 seeds. Experience suggests that when you replant in 7” rows you lose 50% of emerged plants. If you are in 15” rows you lose less. You may have to drive the whole field to touch up certain areas.

Figure 2 - Expected Yield By Row Spacing By Soybean Population

Hula Hoop method for soybean stand count

Example if you have a 28” diameter hula hoop and you measure 10 good plants inside the hoop your stand is 10X 10,000 =100,000

Figure 3 - Soybean Populations with Hula Hoop

Temperature swings when spraying corn

It is recommended to not to spray a post emergent herbicide if above 28 o C or if there is a 20 o C swing in temperature during a 24-hour period. But if you don’t get the weeds controlled there will be a yield hit. Points 1) Smaller corn plants with less leaf surface are damaged less. 2) If really hot better to spray in the evening. The corn plant will break down herbicides in the first 12 hours after application. In the evening corn plants can more easily break down herbicides.

Nitrogen Stabilizers and Rates

If you are applying nitrogen now to corn and not incorporating you need a Nitrogen stabilizer. Here are some basics (talk to your retailer for more specifics) 1. Agrotain Ultra is a liquid product that can be added to UREA or UAN – it contains a urease inhibitor and offers “above-ground” protection of N loss by volatilization. Its application rate is 3.1 L/mT of urea, and 1.55 L/mT of UAN. Agrotain Advanced is a more concentrated version of Agrotain Ultra and performs better on Urea. 2. Agrotain Plus SC is a liquid product that can be added to UAN. It contains a urease inhibitor and a nitrification inhibitor, so offers “above” and “below” ground protection of N loss from volatilization AND denitrification.   Its application rate is 11 L/MT. 3. Entrench is a nitrogen stabilizer that contains nitrapyrin, a nitrification inhibitor. It offers “below ground” protection from loss. Its application rate is 1.1 L/ac. It has a per acre rate, while both Agrotain products have a per treated product rate.

New to the Ontario market this year is two products from Timac Agro. Timac Agro is owned by France-based Group Roullier and is bring traditional materials with a biological component to the market. The two nitrogen stabilizers are Excelis Maxx and Duo Maxx. Excelis Maxx protects against all three forms of N loss and includes Rhizovit, a microbial component that promotes microbial activity in the soil and mitigates the shock of NBPT. Duo Maxx is a NPK stabilizer like Excelis Maxx, but it protects phosphorus and potassium from loss and tie up as well.

One comment I will make, if you are looking at generic vs branded products, ensure they the same concentration per acre when it is applied. Some products have different rates or combinations per acre.

If your retailer carries a product not on this list, let us know, and we will update our product listing for the next time we publish the newsletter.

Figure 4 - Nitrogen Inhibitors in Ontario

Can I patch up my alfalfa stand now where it is thin?

NO! We have received more calls this year than normal about alfalfa seeded last August and volunteer wheat choking out alfalfa. Some years you might get away with Inter-seeding alfalfa last week in May. But this year the soil is so dry and conditions for the next 2 weeks are predicted to be dry, the probability of getting alfalfa to establish now are about zero. Better option is to inter seed oats and get something from those parts of the field. Then in August burn off areas where the stand is thin and reseed alfalfa in August.

Q I am impressed with response to sulphur this year where I used it on alfalfa. Can I apply S now on fields that did not get it for second and third cut?

Ans The reason for the response this spring is because the soil was cold and S was not released from the soil. I would still apply S now before second cut along with 1 lb./ac of boron if you did not already apply boron. Response in second and third cuts will not be as great as first cut, since S is now being released from soils.

Q I just applied a fungicide at T2 timing, flag leaf was fully emerged. Should I still apply a fungicide at T3 FHB timing.

Ans. The information we gave you last week suggests that over the years you can expect another 3 bu/ac yield increase by spraying at T3 if you have already sprayed at T2. This increase is separate from any fusarium control you get by a T3 spray time, Products of choice for fusarium control are Caramba, Miravis Ace, or Prosaro XTR.

Figure 5 - Fungicide Timing and Response in Ontario Wheat (OMAFRA)

T3 Application Products, Rates and Additives

There are three main products registered in Ontario. Caramba, Miravis Ace and Prosaro XTR. All three have two modes of action. Rates, and application tips listed below.

Figure 6 - Fusarium Head Blight Products in Ontario

Miravis Ace Application Video


Wheat Fungicide Flowering Timing Guides

The main reason we apply fungicide at flowering in wheat is for marketability of the crop, and 2nd, the yield benefits. This means hitting the right window if you want to maximize the marketability of the grain from a fungicide application.

Here are a couple of timing guides to help you over the next couple of weeks.

Building Buffers into your Crop Production Plans

These is where the crop advisor can bring great value in the conversation. The value is identifying and quantifying what a producer’s tolerance is for falling of the edge of the table when things go sideways. It could be tolerance for weeds in fields vs. yield loss, how tight they want to run their fertility program when it comes to nitrogen or sulphur on crops like corn or wheat. The buffer is where the conversation is and understanding what areas can be pushed or pulled management wise without allowing margins to suffer. And that comes from knowing your clients’ goals, communication styles and soil types they are working with.

Is there still a benefit to applying a pre-emerge when it’s this dry?

Yes, it will still control a portion of the weeds, just not as many as if you had a rain event to activate the product. And it will be there to work once we get a rain

Early Post Emerge Corn Herbicides

I’m thankful there are quite a few options to choose from. New ones in the last 2 years are; Laudis and Shieldex. The most common products used post-emerge in addition to glyphosate involved either a group 4 like dicamba or a group 27, such as Callisto or Armezon (both Laudis and Shieldex are group 27s). Regardless of which one you work with, all group 27s perform better with the addition of Aatrex (atrazine).

Volunteer Alfalfa in Corn?

My go to products in the past has been dicamba based like Engenia or Marksman. A newer option available is to use Lontrel XC @ 70 to 100 mL/ac + glyphosate.

As a side note, you should not tank mix Distinct with glyphosate, but Distinct is a suitable option if sprayed on its own.

Question – I still need to apply 28% or Urea to my corn. Should I be using a nitrogen stabilizer on my Corn?

Answer – YES. You are still at risk of volatilization. See Nitrogen Stabilizer table above.

Question – Why is my spring cereals looking uneven?

Answer – If you have already applied your nitrogen/sulphur mix, then it’s possibly Manganese deficiency. Also, once cereals start to elongate a couple of days in emergence can cause a difference in height making it look uneven.

Picture 1 - Mn Deficiency in Spring Grain (Note wheel tracks)

Question – When should I apply my growth regulator, and what rate should I apply on my spring cereals?

Answer – Only Manipulator and Moddus are registered on Oats and Barley. See table for application rates and timing. Check with your buyer, prior to treating the crop with growth regulator.

Figure 7 - Plant Growth Regulators in Spring Cereals

“Only paper flowers are afraid of the rain.

– Mary Quant