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The Cropwalker - Volume 4 Issue 16

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Crop Conditions

Weather -last week we had a return of winter. Temperatures dropped to -5 to -7 C in some areas. Some fields in the Harrow area were at the 1-2 nodes and there is concern. As of Monday morning, those fields appear to be OK. Could be small areas in some fields where temperature was low enough to affect plants. Most areas the temp went below zero with some areas getting 2-3” of snow. Pretty well stopped all field activities except spreading fertilizer. Corn and soybean planting is stated and will continue this week. We hope to do a planting survey this weekend. Hopefully there will be a bunch in the ground.


Temperatures for Moddus and Manipulator

For Moddus to work the cereal plant needs to be actively growing.

To the best of my knowledge an application of Moddus will not damage the wheat if sprayed from 0.1 to 5C but it won't work.

I assume no one will spray anything if the temperature is less than 0.1C.

I have tried to convey to follow the postemergence herbicide guidelines for Moddus, assuming that for the most part that Moddus is being tank mixed with a herbicide.

Night-time 2-5C, best to wait 24 hours if possible.

Night-time <2C, best to wait 48 hours if possible.

Follow those guidelines and the cereal should be actively growing I believe, Moddus will work and postemergence herbicide injury will be negligible. Brian Woolley - Syngenta

When applying Manipulator: by itself as long as we do not get frost the night after spraying or the next night, we have not seen any negative effects, (very safe on crop and it still works)

When applying with an herbicide or a fungicide use their product guidelines. The rule of thumb low temp of + 3 degrees day before day of application day after application we support.

We don't recommend all three in tank, can get leaf edge burn on some occasions

Having said that I know lots of C/A's and farmers have done 3 way on their own and if conditions are good or ideal it usually doesn't do leave burn.  Haven't seen damage that hurts crop yield unless we get frost.  Should use higher water vol. 20 gal or more. It seems surfactant load is part of the leaf edge burn that has been observed. Bill Norman Belchim

What Temperatures Seriously Affect Winter Wheat? – Wheat that is dormant can withstand very cold temperatures. Once it starts to grow it can be damaged easier than when it is just breaking dormancy. Once wheat starts to joint (stem elongation), it can be injured by temperatures below -7C. At this stage the developing head is above ground. Once it starts to joint, temperatures below -3C can damage wheat. These temperatures need some clarification. If it dips to these temperatures for a short time the damage is less than if it is at these temperatures for hours. Also, if soil is wet these air temperatures will be moderated by heat given off of the soil.

Low Temperatures Affecting Wheat

Picture 1 - Provided by Susan Gowan, CCA-ON
Picture 2 - Provided by Susan Gowan, CCA-ON

Herbicide Sprayed on Winter Wheat Before Cold Weather

Picture 3 - Provided by Ryan Benjamins, CCA-ON

Comment from a reader in your article on the rule of 3 for spraying, if I followed that rule, it would mean I can’t spray for 6 days.

Reply I made an error in the rule. The rule is 3 days being day before day of and day after temperatures should be 3 degrees or higher. That rule is for ideal conditions. Reality is we can’t wait that long some times. So, then you think about what you are doing. Fungicides have minimal negative affect on crops, so within reason they are not affected by weather. Herbicides are different. You want the weeds to be actively growing to be controlled and wheat to be actively growing to be broken down. Most herbicides are taken up by the weeds and broken down by the crop in the first 10-12 hours or so. This means you want 10 hours or so of good growing conditions before you spray and good growing conditions after wards. Many fields are individual so call if you are concerned. This week I have suggested to growers that they spray in the middle of the afternoon the day after the cold night because the two days after were warm and sunny. And the weather after that did not look favourable for spraying. So, there is a risk to spraying early but also a risk to not spraying. (PJL)

Question - How long do I really have to wait between spraying glyphosate and working the ground?

Answer It is really species dependent. Perennials, and biennials will take longer to kill than annuals. Weeds with a bigger root system like Canada thistle, bindweed take longer. Individual species can be very sensitive to glyphosate. Winter wheat is very sensitive to glyphosate. If it is sprayed on a warm day there will probably be enough glyphosate translocated in the first couple of hours to kill winter wheat. The other thing is that the longer you wait the better the kill. So, in the case of perennials you need the full 48 hours or so for maximum kill. But even if you wait a few hours, you will get some kill. The objective is to wait as long as possible for best kill. If you feel you will not get planting done before the next rain better to accept less than 100% efficacy and get the seed in the ground. Another factor is weed size. Weeds like big dandelions will not be killed in the spring no matter how long you wait. Experience has also shown that weeds like the lamb’s quarters sort of lookalike spreading Atriplex are hard to kill once they get over 2-3”.

Rules of Thumb for N on spring cereals

An increase in spring grain acres again this year. For best yields you need to plant early, make sure you have enough nitrogen and apply fungicides twice. The further north your location, the higher the N rate you should consider. Consider a credit off of these values for manure and alfalfa. With growth regulators, consider stepping up your cereal management with the use of these tools, especially on Oats. Could you push rates higher than what is listed in the table? Yes, but there are likely other things to consider management wise prior to doing that.

Figure 1 - N Rates on SPRING Cereals

Cereal Fungicide 101

Here is a basic understanding of fungicides. If you think of fungicides as herbicides, you might understand better. First there are 2 main groups. Alphabetically they are strobilurins (strobis) and triazoles. The first alphabetical group (strobi) think of them as stopping germination. They prevent spores from germinating. The second group think of them as stopping the spores that germinated from growing more. They prevent mycelium growth. (Apologies to all pathologists).

Since fungi go through a very fast life cycle it is impossible to stop all the spores from germinating or stop all the germinated spores from growing. And since spore formation is a function of the weather and the disease it is not very possible to say one product is a lot better than another. Many products are good against many diseases, but certain products are BELIEVED to be better against some diseases such as white mould.

There are differences as to how fungicides move in the plant and how long they stay active. Sunshine and rain can break them down. However, the strategy is to not depend on one group or the other. In fact, many of the better fungicide products are a combination of the two groups. The new product Miravis Ace from Syngenta has another group. Miravis Ace has 3 modes of action.

Figure 2 - Average Winter Wheat Nitrogen Response

This chart gives a relative importance of fungicide timing. T1 is at growth stage 30-31 - stem elongation or herbicide time. T2 is at flag leaf and T3 is fusarium head blight timing. There are other research trials that show different yield increases. Part of it is the variety used. Some varieties have better resistance to certain diseases. So, depending on the variety and the year you could get different results. Bottom line, you need two fungicide passes to maximum wheat yields.

Q What fungicide gives the least leaf burn with Buctril M?

A (from Jonathan and others) Tilt gives the least burn with Buctril M. The bromoxynil in Buctril M increases leaf scorch (Infinity can also have this issue, also has bromoxynil). Looks bad but probably does not affect yield. Any fungicides with a strobi will give more leaf scorch. You can decrease this scorch by using higher rates of water.

Q Can I spray dicamba to control alfalfa before I plant corn.

A NO Dicamba should only be sprayed post emergent on the corn. If you spray before the corn emerges there is a chance that the dicamba will get rained into the topsoil. If the corn plant sits in cold wet soil as it emerges it will take some of that dicamba up and affect the plant. You won’t see the effects until 4-6 leaf stage. To control alfalfa before planting corn just use glyphosate and be ready to apply glyphosate and dicamba post when both the corn and alfalfa are up. Seldom can you kill alfalfa with one application of glyphosate.

Comment from a reader on this article

Q – I run a coulter cart in front of my drill, how deep should I be running it?

A – You do not want to dry out the seed bed when drill or planting behind the last pass of tillage. The last tillage pass (even if it is on the front of the drill) should be ¼ to ½” ABOVE the intended planting or seeding depth.


I completely disagree with this. I tried it that way and was not able to get good seeding depth because of the variation in depth when I tried to do this. Now I run my coulter cart at least 2 inches deeper than where the seed will be placed. I use the press wheel to control the depth and Keeton seed firmer to keep seed in place.

Editor Response – I don’t doubt you are getting better results with what you are doing, however, I’d be inclined to ask the question why you have to do that. My comments are from several conversations with two different mainline manufacturer reps.

What products should be promoted by retails…

The ones that make big dollars. Huge dollars. For the farmer. And the retail. They both need to make money. But I do not think very many operations selling crop inputs go through this exercise, which is why I am writing about it. If you are a retailer, write down the 5 BIGGEST agronomic opportunities in your area to help your farm customers improve crop production. Then write down the margin potential for those opportunities for you if you promoted it. Pick the top three that put the MOST money into the farmer’s pocket and put money back into your business in supporting them. Plan some field plots/demos, newsletters etc to promote those practices or products. That is how you build a profitable, customer focused business.

Fundamentals of Crop Production

Are fundamentals for a reason. These are the laws of crop production (or being a world class basketball player, if that’s your thing). Plant into a lumpy seed bed, get lumpy seed bed results. Spray weeds on the late side, get weeds sprayed on the late side results, you get the gist. It is not that there are situations where you get acceptable results by doing things outside of norm or trying to bend the “laws” of crop production, it is that the results tend to be more variable than what the expected range response would normally be. As you go through putting crop in the ground this spring, focus on excelling to get the fundamentals down. What would make them more efficient to execute on? What would ensure they get done and are repeatable? How do you avoid the pitfalls that hold back from achieving the basics?

Boundary Files

If there is one thing almost every farm operation needs from a GPS/GIS management standpoint, it is start with properly structured boundary files. The means having all fields named by Grower, Farm, Field. And please do not use the number “1” as the field “name”, put the actual field name. If the farm and field have the same name, put down “Smith” for both the farm and field name. I am running into more and more situations around data management/remote sensing and general crop management where having this layer is critical to keep things properly moving forward. And in speaking with one GIS specialist, naming all the field layers “1”, can lead to an exercise in frustration when moving the data to another GIS program.

What Winter Wheat Varieties are Most Responsive to Fungicide Use?

Luckily the Ontario Cereal trials have both a managed and unmanaged replicated trial for each wheat growing zone. Here is a link the reports. The most responsive across all site years for Areas 1 and 2, the last 5 years was Cruze and 25R61. Least responsive to fungicide use was over the last 5 years was Measure (4 years of data). I did not include Areas 3 or 5 due to a small data set (1 or 2 years).


Soil Erosion Management

One observation I had today, was the impact soil type had on how to properly manage soil erosion. In this case water is moving soil off the field due to lack of proper infiltration during rain events, causing heavy run-off. This producer is trying to plant cover crops to improve infiltration, so it will be interesting to see how they mitigate erosion through management.

Picture 4 - Soil Erosion on Clay Soil due to Water

“The point at work isn’t doing every task at 80% but understanding which tasks can be done at 50% and which need to be done at 100%. Performance isn’t doing everything equally well. Performance is going all in on the things that make a difference.”

– Shane Parrish