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The Cropwalker - Volume 4 Issue 23

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Crop Conditions

Weatheracross Ontario rainfall and soil moisture are variable. Some fields got 2” and a few kilometers away nothing. Eastern Ontario is still very dry. As of noon June 14, rain was falling in the Winchester area of Eastern Ontario. Earliest wheat in Essex in the soft to hard dough stage. The hot weather during kernel fill will decrease yields. Hot weather means the plant will go through the grain fill stage quicker resulting in fewer hours to fill the kernel. High night time temperatures adversely reduce wheat yields. The exact cause is not known but research has shown it is true. As we experience global warming one fact is that nighttime temperatures are increasing. Sort of the good news is areas in Central Ontario will be filling under cooler conditions.  Soybeans expect to see first flower next week in earliest fields. Respraying continues. No manganese deficiency yet but expect to start seeing it in fields that did not get rain. Also watch for aphids. They are probably at low levels in some fields. You just need to monitor them. If you see Lady Bugs, check for aphids. Spring cereals Earliest fields are in boot stage. If you have not sprayed a fungicide for leaf diseases make plans now to do so. Check for cereal leaf beetle, Mn deficiency and aphids when staging these fields. Forages Second cut is advancing quickly. Some fields have alfalfa weevil. Probably too late to spray most of these fields. New alfalfa leaves will be a lighter green. If you see feeding damage but new leaves are OK that means they have finished feeding. New seedings are all over the place from looking good to never germinated due to lack of rain. These fields could be seeded with oats to at least get something, then harvest oats and summer seed mid-August. Leaf hoppers have arrived. If you really need forage suggest you prepare to spray by end of June. Products registered include dimethoate (Cygon/Lagon 480) as well as Matador, generics and Sivanto Prime. From my experience dimethoate is product of choice. It has Knock down and residual. According to Syngenta, Matador should give similar results if spraying under cool conditions.

Picture 1 - Alfalfa Weevil feeding in Alfalfa (new growth unaffected)


Things to do this week

1.     Quick check wheat fields for stage, weeds that need a preharvest and armyworm.

2.     Check soybean fields for weeds, soybean aphids. Check droughty areas. Watch for manganese deficiency.

3.     Check alfalfa fields for weevil and leaf hoppers.

4.     If you store grain on farm, clean all bins and clean up grain outside the bins.

5.     Book your soil sampling if you haven’t done that already.

Tips on how to control bigger weeds in IP soybeans

I recently read on an Ontario -based newsletter that suggested when weeds get bigger in IP soybeans you will get better control by making sequential trips. This is absolutely correct. Separate broadleaf weed control and grass control when weeds get bigger in IP soybeans. Then it went on to suggest you spray grasses first. This is absolutely wrong. Before Roundup Ready soybeans we all had our recipes. But one rule was You must spray the broadleaf weeds first because;

1.     Broadleaf weeds are harder to control as they get bigger. Once broadleaf weeds get to be 3-4” they are practically impossible to control in IP soybeans. Grasses are easier to control at bigger stages.

2.     Broadleaf weeds reduce yield more than grasses.

3.     Many broadleaf herbicides cannot be sprayed after soybeans flower. Grass herbicides are less harmful to soybean flowers.

The same comments hold true for edible beans.

Remember to spray at 20 gallons of water for most post broadleaf weeds in IP soybeans. Addition of higher rates of surfactant and UAN can increase broadleaf weed control.

In Roundup Ready soybeans there is a stage where some weeds like lamb’s quarters become difficult to control with glyphosate. Get them when they are small.

Manganese deficiency in soybeans Manganese is taken up in the Mn ion form. When soils are dry there is oxygen in the soil and manganese is converted to manganese oxide which is plant unavailable. If it rains this forces oxygen out of the soil and manganese oxide quickly converts back to manganese. Which fields to watch? Fields that did not get rain. Muck and high organic matter soils always show Mn deficiency. If you have a Mn soil test, check it. Soils with a high pH (above 7.5-7.6) can be prone to Mn deficiency. First symptoms will be just a light green colour. More severe deficiencies show as light green between the veins.

Additional note on Manganese

As I am driving around to check fields, I am seeing A LOT of Mn deficiency in spring cereals. If you still have yet to apply a 2nd fungicide on spring cereals, consider adding a foliar Mn product to them to help correct this deficiency. If I can pick out from the road going 80 clicks, on many fields, your crop is suffering.

Should I sell my wheat straw?

I have looked at the book value of N, P and K in wheat straw figuring about 50% of the N in wheat straw will be there next year. Based on MAP at over $900 per tonne and 0-0-60 at over $600 a ton the N, P, K value of straw is about 1 cent per pound. There is also a value to the organic matter and some micro nutrients. The exact nutrient level in straw is variable depending on things like how much rain on the straw after harvest, variety and maybe soil nutrient levels. Currently there is less demand for straw than last year due to current straw supplies from last year. It is possible there will be a need for straw in eastern Ontario where there is currently a lack of soil moisture. I am hearing prices of around 3 cents a pound which I would take. If your soil is testing high for P and K and/or you will be applying manure to a certain field I would certainly sell the straw. If not selling for the first time in some time, make sure you can spread straw effectively. Poorly spread straw can surely miss up the cover crop and the following year’s crop establishment.

Potato Leaf Hopper in Alfalfa and Edible Beans

Generally, leaf hoppers start to show visible damage on edible beans and alfalfa around first of July. Last couple of years they have been showing up earlier. If you have dry conditions, you are apt to have leaf hopper damage. You can sweep and look for symptoms but by that point it is too late. Some growers who have this insect many years will spray once the regrowth gets 2-3” of new growth. Product of choice is dimethoate sold as Cygon/Laygon.

Figure 1 - Alfalfa PLH Threshold with Sweep Net
Figure 2 - Edible Bean PLH Threshold with Sweep Net
Picture 2 - Potato Leaf Hopper

Fusarium or Take all

These two pictures show the difference between Fusarium and Take all. Fusarium will infect individual kernels while Take all affects the whole head.

Picture 3 - Fusarium in Wheat
Picture 4 - Take-all in Wheat

Fungicides for Spring Grain in Head

Products that are safe include Caramba, Folicur, Proline, Prosaro, Propiconazole or Tilt. These are all triazoles. You should not spray the strobilurins (strobis) on cereals that are in head (mainly barley or spring wheat. Headline AMP is registered to spray on Oats in head.

What is this symptom and how come it is just around the outside of the field?

This is classic potassium deficiency. The whitish spots at the margin of the leaves. It is probable that fertilizer rates around outside of the field were not as heavy as inside of field. Soil test to check. Also use a spreader that gives an even spread to outside of field.

Picture 5 - Potassium deficiency in Alfalfa

OMAFRA Pre Side dress Nitrogen Test Results

The results of this cross Ontario survey have the average test at about 13 ppm. This is similar to last year. Number is really a bit irrelevant to you. You have to do your own test to see what you have. It is a bit like saying average age of Canadian farmer is 55, similar to last year. Not relevant to you. I still use the Ontario Nitrogen calculator. http://www.agtest.com/n_calc.cfm Is one site. I find this easier to use than the one on http://www.gocorn.net/v2006/Ncalc/Nitrogen%20Calculator%20-%20GOCorn%203011810.pdf

Question – What can I plant after wheat that will allow me to get a fall and spring forage crop, and then I can plant to soybeans?

Ans – A few have tried Oats with Cereal Rye, with the Oats making up the bulk of the fall forage, and the cereal rye in the spring. One I would be interesting in trying is fall Oats with an Italian ryegrass, it would be worth posing the question on if the cutting dates/times will line up as well as it would with Cereal rye, along with the expected forage volume/seed costs. Another is oats and winter triticale. Some New York folks are big on winter triticale. Have asked for Ontario research but none on this question.

Question – The Lontrel I used with the glyphosate seems a bit slow on the volunteer alfalfa? Would glyphosate on its own have been just as fast?

Ans – I doubt it. If the alfalfa was slow to die, it may have been due to the weather conditions around the time of application. Most group 4s show activity in hours when they are applied in the proper conditions.

What product is the best for respray in IP/NON-GMO soybeans?

Lamb’s Quarters – high-rate pinnacle; Basagran Forte or Reflex can have activity if small enough

Pigweed – Blazer or Reflex; Pinnacle has activity, but it is likely group 2 resistant.

Ragweed – Reflex

Nightshade - Reflex

Annual grasses – typically Assure, if you want to mix it with Reflex or another broadleaf herbicide.

Question - I have variable emergence on my soybeans, can I respray too early?

Ans – No, OMAFRA trials conducted in 2006 and 2007 found less visual injury when applied early (prior to the 2nd trifoliate leaf stage), than at the 2nd trifoliate.

Top 5 management practices overlooked in Alfalfa production (opinion)

1.     Phosphorus fertility at establishment

2.     Potassium fertility to maintain stand longevity.

3.     Early season sulphate sulphur (20 lbs/ac minimum)

4.     Insect scouting and management

5.     Early season fungicide use for leaf retention

Bean Leaf Beetle vs Grasshopper Feeding vs Slug Feeding

Getting a few questions on insect feeding on young soybean plants. There are three possibilities I am aware of. 1) Bean leaf beetle feeding, which looks like a hole punch went through the leaf. 2) Grass hopper feeding, which looks like large bites with clean edges from the outside of the leaf. 3) slug feeding, has irregular patterns, and leaves a trail of slime across the leaf surface. You should be able to see grasshoppers. Slugs are not likely to be an issue if ground is dry. Slugs will leave a slime trail.

Minimum number of plants – It’s variety/hybrid specific.

A comment from one seed representative is that the final stand counts on corn and soybean populations should be variety or hybrid specific. In the future, if your seed supplier is inspecting your stands that are under consideration for replant, ask them if they have this information (whether based on research or experience).

Question - Nitrogen Fertilizer is UP quite a bit since I last priced it, how much should I be putting on?

Ans – The laws of supply and demand are at play here, but we write an agronomy newsletter, not a micro-economics one, so here is the brief answers below. I have put together the following table for 1 corn grower on their land at various price points and yields to answer a few questions, what rate based on the price of N, and what N rate based on yield potential. After running through a few scenarios, the corn to nitrogen price plays a lower influence on the right rate than what the yield potential of the field, soil type, or previous crop. With yield potential being the biggest factor.

Figure 3 - Nitrogen Rate by Corn Yield/N Price (OMAFRA Corn N Rate Calc.)

N rate on Corn/Water Requirements

For those trying to fine tune the N recommendation by adjusting in-crop, Caleb Niemeyer’s Master’s Thesis found that about 80% of yield variation is due to rainfall from V5 to V12. With the most critical being at the V10-V12 leaf stage. If you are daring enough, look at forecasted rainfall for your area for that period, based on this data, it will provide insight on the single biggest driver for corn yield potential (and appropriate N rates) for the growing season. Alternatively, is to look at using the combination of a soil moisture probe and a weather station.

Soil Moisture Probe for In-Crop Decisions

One system forecasting yield potential using soil moisture data is service provider Crop Intelligence. Using forecasted rainfall (0, 25%, 50%, 75% and 125% of 30-year average) plus available soil moisture, the Crop Intelligence app provides an expected yield potential based on current available soil moisture, and the five rain fall scenarios for your crop. This allows those making in-season input decisions (mainly nitrogen and fungicide applications) to be in the driver’s season with known information and scenarios.

Figure 4 - Soil Moisture Availability by Depth (Crop Intelligence)

Metribuzin/S-Metolachlor/Group 14 Injury in Soybeans

Picture 6 - Metribuzin Burn on Cotyledon (Boundary + Broadstrike)
Picture 7 - S-Metolachlor (draw string effect) plus Metribuzin splash up (burn) - Boundary
Picture 8 - Group 14 Injury on leaves from splash up (Conquest + Authority)
Picture 9 - Overlap on headland, resulting in injury

Step Change vs. Incremental Improvement

I wanted to make a brief comment on step vs. incremental improvements. The reason is that you can use “LEAN” principles to make incremental improvements for only so long (say 3% per year), and then you reach a point where the piece of equipment or practice no longer fits with what you are hoping to accomplish. At this point you are looking for a new way of doing things rather than just perfecting the process.

One example in crop production is shifting away from full width tillage to adopting strip-till. For those adopting this practice, they are reducing the number of passes and pieces of equipment required to establish a seed bed and apply fertilizer. Once they have adopted strip-till, then it is focusing on “LEAN” principles to get it as efficient as possible.

Do not take this as if I am opposed to tillage, I’m not, but it needs to serve a purpose. And that is to incorporate nutrients, provide some weed control, and establish a proper seed bed. But there are also new ways of doing this that were not available 15 or 20 years ago.

Grass Herbicides in Soybeans/Edible Beans

There is a lot of new players in this space in the last couple of years. Some are products are designed for volunteer corn control in the Round-up Ready soybean acre, but because of the price point are being used in the non-gmo soybean and edible bean acres. The issue is that some of these do not tank-mix well with the actives used on the non-gmo soybean or edible bean herbicides OR lack the proper surfactant to make these products work.

Figure 4 - Summary of Common Grass Herbicides used in Soybeans

“If I had asked people what they wanted, they would have said faster horses.”

— Attributed to Henry Ford