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The Cropwalker - Volume 4 Issue 19

Always read and follow label directions.

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Crop Conditions

Weather hot and dry for most of the province. We may have set a record for the most acres planted in a few days. Weather looks like we may be in for some dry periods. We need to be in drought probable mode. The Haldimand area again this year has very little crop in. Ground has been too wet. They hope to get going this week. Winter wheat earliest in Essex/Kent has head emerging. Most other fields are 2nd node to flag. It takes about 10 days to go from 2nd node to flag leaf most years. This year, it will be fewer days. Unless heavy weed pressure, I suggest no more herbicides on wheat. Corn probably at 80+ % planted as of May 17. Earliest poking through. We are now about the same as last year. In 2020 we had 83% planted by May 17. Soybeans about 35-40% planted as of Monday morning. Planted will be full out all week. Last year we had 31% planted on May 17 Spring grain is emerging well and quickly. Now is when you need weed control. Forages new seeding is at first trifoliate and ready for weed control in some fields. Established stands have grasses heading or almost there and alfalfa coming very quickly with heat. Alfalfa weevils expect it to start feeding in traditional areas.


Things to do this week.

1.     Check all planted corn fields. Now is when you can replant areas if planter was missing. Check for emergence issues. This will be a good year to see how even the rows are planting. When there is lots of rain everything comes up. In a dry year expect more uneven emergence

2.     Check for weed escapes. You need rain to activate herbicides. Do not wait too long for respraying.

3.     If you have forages check stage and check for weevil.

4.     Thank your input supplier for their help this spring. If it were not up to your expectations tell them how they can improve.

Dry weather strategies (Patrick Lynch)

Tillage keep to a minimum, and as shallow as possible. IF you have the option, consider tillage at night and plant in the daytime. Sun and wind dry the soil. If not possible, consider pulling a packer behind tillage and plant as soon as possible after tillage. Generally, this time of year someone gets a down pour which leads to crusting. If this happens get crust off as quickly as possible, rather than waiting to see if it will form. Planting depth for soybeans a conglomerate of agronomists has figured the best bet is to plant 1 ½- 2” and no deeper. If you do not have moisture at that depth, plant and you will have to wait for a rain for emergence. Probable that you will have uneven emergence in that some parts of the field will emerge sooner than others. Not a big deal with soybeans. For edible beans you must wait for rain and then get seed into the ground as soon as possible. I do not like planting edibles deep, and they must come up even. Edibles yield best if planted around June 1st. Forages thinking that dry weather will continue consider getting first cut off as early as possible and count on there being enough soil moisture for a good second cut. Pre emerge herbicides need about ½” of rain to be activated. Options are to respray with glyphosate on Roundup Ready crops or Liberty on Liberty tolerant crops or light tillage to remove seeding weeds. Do not wait to see if they will die. With this dry weather they will grow and harden off quickly.

Lamb’s Quarters is a bad weed.

This weed has been identified by Ontario agronomists as one of our worst weeds. It was introduced into North America by immigrants who brought it as a salad green. It produces a very large number of seeds per plant. Large individual plants can produce over 70,000 seeds per plant. These seeds are classified as “long living”. Current populations are resistant to triazines (atrazine, Sencor) and probably group 2 herbicides. There have been many cases where glyphosate does not control them. Control is most consistent when they are 2.5 cm (1”) or less. Once they get bigger, they start to deposit calcium on the leaves. According to Mike Cowbrough OMAFRA “once lamb’s quarters get to be 10 cm (4”) higher rates of glyphosate are needed. In information that Mike shows indicates that control is best with glyphosate when a pre emerge herbicide is applied. Take home do not let lamb’s quarters get big if counting glyphosate to control them.

Keep an eye on Lamb’s Quarters Size!

If you read the label for post-emerge herbicides like Basagran Forte or Pinnacle the maximum leaf stage these products are labelled for Lamb’s Quarters, is up to 8-leaf (Basagran Forte), or up to 10 cm (Pinnacle).

To check to see what stage these weeds are at, this means getting on your hands and knees. And do not wait until the maximum leaf stage to make the application, but the over riding factor is if these weeds are actively growing. 2021 is already starting to look like it may be a challenge in the weed control department if the current weather patterns remain for the next couple of weeks.

Picture 1 - 2 leaf Lamb's Quarters (Brittney Littlefield)
Picture 2 - 4 leaf Lambs Quarters

Bayer Fungicide Registrations

Bayer has announced that they have received registration for Prosaro Pro - Prothioconazole (group 3) tebuconazole (group 3) and fluopyram (group 7). It is registered for application on Barley, Oats, Triticale, and all wheat classes. The target application timing for this product in wheat is at T3 (Fusarium Head Blight).

Bayer also announced they have received registration on Delaro Complete, a corn and soybean fungicide (like Stratego Pro with an added active – fluopyram (group 7). Application timing will be at flowering in soybeans or at tasseling in corn.

Will provide additional information on both these products closer to application timing.

Fungicides for Winter wheat Strategy (Patrick Lynch)

You must keep the flag leaf clean. Consider spraying once the flag leaf is fully extended or almost fully extended. Then watch weather in your area for development of fusarium. If dry conditions continue fusarium may not be a treat. If we get into rust conditions you want the top leaves protected.

Increase Straw Yield

Data forwarded by BASF shows that spraying spring wheat with Caramba increased the straw yield by 303 lbs./ac and the grain yield by 7.8 bu/ac. But, if you also sprayed Headline AMP at growth stage 32 (2nd node), the straw yield was 644 lbs./ac vs. check. This also increased grain yield by 10 bu/ac vs check. This data was from spring wheat. BASF suggests that you should expect equal or higher yield response from winter wheat.

Cobutox/Embutox on Seedling Alfalfa

Cobutox or Embutox tends to be applied on the late side, time gets the best of us. Label states 1 to 4 trifoliate for crop safety purposes. Can go earlier, better to base on weed stage than alfalfa stage, but if possible, would not recommend going later than 3 trifoliate. Controls Lamb’s Quarters, Pigweed, and Ragweed. Add 28 mL/ac of MCPA Amine to improve control of Wild Mustard/Vol. Canola.

Weed Control in Spring Cereals – What is registered, what’s crops safe and what to control?

If you can spray it on winter wheat, it is crop safe on spring wheat and Barley (Simplicity is an exception). Oats are the most sensitive. Here is a list a list of the most common cereal herbicides. I have updated this table from 2020 to reflect new label registrations.

Figure 1 - Spring Cereal Herbicide Crop Safety

Weed Control in Winter Wheat Flag Leaf Emerged

Once the flag leaf emerges you must be careful spraying. Typically, by this stage weeds like chickweed, dandelion and field violet have done their damage as far as yield reduction. Generally, once weeds flower, they have done maximum damage. If you have small ragweed and lamb’s quarters, you can control them. Certain herbicides can be harder on wheat than others. Once flag is visible the number of products that can be applied really is a handful, the chart below from North Dakota State provides a good visual. Please note that not all trade names/actives have the same registration in Ontario. And as the graphic says, the label is the law.

Figure 2 - NDSU Herbicide Application Windows on Wheat

Soil Crusting – Rain, especially heavy pounding rain, followed by bright sunny days. leads to crusting. If you leave a footprint when you walk across the field, you do not have a crust to worry about. Once you see a crust developing in the heaviest part of the field, know it will develop in the rest of the field. If you have a corn field that normally crusts, consider rotary hoeing before the crust develops. A rotary hoe will work if you get to it soon enough. The best rotary hoeing will occur when the ground is still wet in places. If the crust has already developed growers have successfully used corn planters, Aerway, RTS, and even cultivators to remove a crust. The process is not rocket science. Do two passes and if you like what you see, keep going. If you do not, try something different. If you have a crust in a soybean field the rules are different. Soybeans do not recover from crusted soils as well as corn does. Generally, your best bet on soybean fields that have crusted, and the beans have not emerged is to replant. The replant policy from seed companies and crop insurance does not discourage replanting.

Pre-Emerge Corn Herbicides

A brief opinion on which pre-emerge corn herbicide should be used where (based upon opinion and grower experience). Mileage may vary on your weed spectrum and management practices.

Acuron – Best fit has been growers looking for full-season, annual grass and broadleaf control. Must be applied pre-plant to 6-leaf. Good PRE option for conventional corn, provided you have a plan to control perennials in-crop.

Converge XT – Found best success at the 20-ac. rate when targeting warm-season broadleaves (Lamb’s Quarters, Pigweed, Ragweed). Use the 15-ac. rate if targeting Proso Millet. Weakness can be grasses and perennial weeds, if high or severe infestation. Narrow window for application at PRE to 2-3 leaf. Label suggests the need to reduce the rate to 30 ac/unit when tank mixing with glyphosate on emerged corn (reduces the risk of white flash on leaves).

Engarde – pre-mix of Elim and Callisto. Add Aatrex for more consistent broadleaf control. Crop safe from PRE to 2 leaf.

Focus/Zidua – Group 15 like Dual or Frontier. Adds residual bluegrass control. Do not apply Focus in-crop. A tank mix partner is suggested (Aatrex or Marksman).

Dicamba/Marksman – Corn must be planted prior to application. Less risk of crop injury if corn has emerged. Provides both knockdown and residual. Higher rate gives longer residual.

Halex GT – Is a one-pass program for the one to three leaf in-crop on RR corn. It could be used PRE, prior to crop emergence, however, you may have some late season perennial weed escapes. Do not apply in-crop on conventional corn or with 28% UAN.

Integrity – Best for growers on worked ground and wanting to apply 28% UAN. Can work on no-till or strip-till corn, provided perennials are not too big. Otherwise, regrowth can occur if the glyphosate does not translocate. Even at the high rate (0.45 L/ac), you may have to come back into cleanup with glyphosate. Because of this, not targeted for conventional corn.

Primextra II Magnum –Can be strip-tilled, worked in, left on-top or used in-crop. While the 1 L/ac rate has been promoted extensively, best performance has been at the 1.2-1.6 L/ac rate, especially when any incorporation occurs. Growers that use this product on its own pre-emerge will need to plan on a clean-up spray in-crop. Performs best when combined with a group 27, like Callisto, or a group 4, such as dicamba, in-crop.

2nd Pass of Wheat Timing – Do it already!

If you have winter wheat, you should already have your 2nd pass of nitrogen on. Hard Red Wheat research conducted by C&M Seeds and Yara suggests that waiting until the flag leaf has emerged will cause a yield reduction if using a product like 28% UAN streamed on over the top. Yield losses were minimized if a dry product like AmidaS (Urea/AMS prills) were used instead.

Figure 3- Wheat yield by N timing/source (C&M Seeds/Yara)

Weed Density Ratings

Typically, a field requires “action” if you have a pressure rating of more than 5 light or 2 medium, or 1 high weed rating, depending on the weed species present.

Figure 4 - Weed Population Thresholds
Figure 5 - Yield Losses Due to Weed Species in Corn and Soybeans
Figure 6 - PMRA Herbicide label Claim Requirements

Question – I am a dairy farmer, where should I be investing in precision ag?

Answer – If you do not have autosteer, get it. You make more trips over the field than most crop farmers, yet many dairy farms have a lower adoption rate. For example, if you have 1 to 1-1/2’ of overlap on your 12 ft mower, you are running 8 to 12% overlap over the whole field. But it is not just the mower pass, on all the passes you will now have more passes than necessary because of that overlap. On 100 acres of forage, this means cutting an extra 8-12 acres that did not even exist, on each cut, for the year. At 4 cuts this would mean up to an extra 24 to 40 acres of time mowing, raking, harvesting/baling (realize you will not take the overlap number to zero). A brief survey suggests that just on mowing, this would mean savings about $500-1000/year per hundred acres of forage at custom rates.

Precision Ag – Leap Frogging Population by Field to Population by Zone

A brief conversation with two other agronomists on managing seeding rates and plant populations. We all agreed that not many producers are managing population by field today, let alone variety. As precision ag/variable seeding adoption increases, we will likely see seeding rates by field/hybrid leap frogged by going straight to seeding rates by zone (much easier to do stand counts when you know how to manage for seed mortality!)

Forage Forum with Christine O’Reilly OMAFRA Forage Management Specialist

Q What stage should I be harvesting my cereal rye?

Ans for optimum feed value and yield you should target the boot stage. At the boot stage cereal rye can be 18% protein and under 50% NDF. By head emergence CP will be 13-14% CP. Cereal rye matures quickly so once you can feel the head in the boot get the haybine ready.

Q This year grasses are significantly ahead of alfalfa. But alfalfa is maturing quickly. What things should a producer consider when taking first cut?


1.     Feed value. For highest feed value harvest when grasses are at the right stage. Grasses start to lose feed value once they start to head. Legumes maintain quality until late bud stage. So, trying to get grasses before they head and legumes at late bud is the target. Then hopefully with an early first cut, second cut will get off to a quick start.

2.     Soil fertility. If fertilizer was not applied this spring, then fertilize or manure right after first cut.

3.     If applying manure, we want it on before new growth is significant. Typically, this means we want manure on 48 hours after cutting. If you are making dry hay, it is hard to get manure on to an alfalfa field without damaging the alfalfa.

4.     Alfalfa weevil are present in the traditional weevil areas. Cutting is the best way to control weevils. The threshold for alfalfa weevils is 40% leaf tip feeding with 2 or more active weevils per stem.

“My daddy spent his life lookin' up at the sky

He'd cuss, kick the dust, sayin' son its way to dry

It clouds up in the city, the weather man complains

But where I come from, rain is a good thing”

– Luke Bryan