The Cropwalker - Volume 4 Issue 17

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Crop Conditions

Winter wheat - earliest fields are at second node and looking really good. Later fields are just starting to elongate. Second application of nitrogen is occurring as conditions allow. I would rate current weather as medium for diseases to develop. Most diseases like warm and moist. We have moist and warm days, but nights are cooler which slows disease development. Weed control is happening. We did a summary in Volume 4 Issues 14 and 15 this year.  Cereal rye should be burnt off, if not already done, so if you are planning on planting corn or soybeans into that field, get it done. Corn planting is about 15-20% complete with a small number of growers well on the way. This is similar to this date last year. Soybean planting is just started. I would say that as a group Ontario farmers do not believe you should plant soybeans as early as you plant corn??? Forages are really looking good. If considering spraying Priaxor for higher yields and quality this is the week to do it. Priaxor is registered for 2 weeks before harvest but 3 weeks should give better returns. Current weather is conducive to diseases in forages.

Articles

Errata

Last week we suggested that there are 3 actives in Miravis Ace, when in fact there are two actives. Miravis Ace is registered for spring, winter and durum wheat, and brings together propiconazole (Tilt - Group 3) and ADEPIDYN (Group 7), Miravis Neo used on corn has 3 actives (Quilt (Group 3, 11) + ADEPIDYN (Group 7).

Tillering and Stem Elongation in Winter Wheat

Wheat continues to move through staging. Here is a quick guide to Zadok’s staging. Zadok’s 20’s -> 21 = 1 tiller, 22 = 2 tillers, 23 = 23 tillers etc. and stem elongation. Zadok’s 30 = stem has started to elongate, 31 = 1st node, 32 = 2nd node. To count tillers, first find the main stem, this is the biggest stem in diameter and typically the tallest leaf. (Red arrow below). Attached to the sides of the stem are the tillers. When planted early enough in the fall, with enough growing degree days, you will have 1-3 tillers going into spring. Late planted wheat may have no tillers or 1 tiller. The second picture below shows the difference between a fall-initiated tiller (dark blue) and a spring-initiated tiller (light blue).

Stem elongation is when the main stem, and tillers that will produce heads, start to initiate the reproductive phase. Agronomist Emily Jones has a good example below of the stems elongating, and how to find the first node.

Question Should I apply a fungicide at T1?

Answer If you look at the data from last week you can expect on average 1.6-2.0 bu/ac yield increase. The 1.6 is if you do not apply a fungicide later, the 2.0 if you apply two more applications of fungicides. There are a lot of on farm trials showing a higher yield increase by spraying at T1. While T1 application does not give as big a yield increase as the next 2 applications, it is still worth doing. There is also an increase in the quantity and quality of straw. The exact yield increase really depends on what diseases develop. If we get bombarded with stripe rust the yield increase will be higher. This spring Jonathan is seeing quite a bit of Powdery Mildew and Septoria in wheat (variety specific). Get out and check if you have not.

Wheat Straw Length – (notes from Dr. Duane Falk formerly U. of G.) – Genetics is the main factor in straw length. Other factor determining wheat straw length is weather. (heat, length of day and intensity of light). Wheat changes from vegetative to reproductive depending on heat and light. Some varieties like the old R47 make the switch mainly based on heat. Thus, in hot years R47 plants switched over to reproductive early. Varieties like old lodging prone AC Morley, switch from vegetative to reproductive based on day length. If there is extra heat when it is still in vegetative mode it could produce another node and be taller than other years. The sunlight during elongation also affects straw length. If it is cloudy and cool from start of elongation until heading, the straw will be taller than if it is sunny during this time. Typically, straw length will vary but total straw dry matter will not change much. The cells merely get longer.

Why Multiple Modes of Action for Fungicides (Simplified version)

Last week we wrote about how strobis prevented spores from germinating and triazoles prevented mycelium from growing if they germinated. Fungi go through a rapid life cycle with lots of cross breeding. It is fairly easy for a disease to build resistance and get by one mode of action. If you have two modes of action, one will help stop spores from germinating and the other will help reduce the amount of mycelium growth of disease that got past the fungicide that should have stopped the spore from germinating. Why not just use a triazole fungicide to stop mycelium from growing? Because some of the fungi will be resistant to that fungicide and mycelium growth will not be stopped.

Ohio Research on cold weather and wheat yields (C.O.R.N. Newsletter: 11-2021)

They placed wheat plants in growth chambers for 15 minutes to measure the effect on yield. Their data showed a 5% reduction in yield for wheat that was subjected to -7 C at the first node and 50% reduction if wheat was at 3rd node. They acknowledge that the amount of damage depends on how long the temperature dropped and soil moisture conditions. They also said it would take 2 weeks to know the effect of cold temperatures.

Notes on figure 2 - Temperature (15-minute duration) at which wheat yield was reduced by 5%, 10%, 25%, and 50% at Feekes 6, 8, and 10.5.1 growth stages. (Data from Alt, Lindsey, Sulc, & Lindsey, 2020).

Cereal Leaf Beetle (CLB) Parasites

In the late 60’s CLB parasites were released in various parts of Ontario. These parasites were very effective in controlling CLB. But in the last 10-15 years CLB has become a problem. In New York researchers are surveying farms and establishing how wide spread CLB is. They are also collecting parasites and trying to rear them to release them. I checked with Tracy Baute OMAFRA and she said in Ontario they are collecting larva to see if parasites are still effective in controlling CLB. So, for this year you will just have to watch.

Question – I want to strip-till a field but I am unable to due to equipment restrictions. What would you recommend, spreading and no-till the corn? or working it in with Cultivator?

Answer – Since you have RTK guidance, I’d be inclined to try banding the MESZ/Potash with your cover crop drill and then come back and plant beside it 2 inches away from the band. Otherwise given the soil test on that field and lack of dry starter on the planter, working it in is likely the best course of action.

Question – My fall burndown was not effective, what happened?

Answer – Seeing this on multiple fields. I am expecting some fields were sprayed off too late into the fall. If alfalfa and red clover, probably too cold for the dicamba if it was used. If only glyphosate you should not expect 100% kill.  This coming fall plan on trying to burn off those fields earlier so the herbicide has more time to translocate into the plant. For fields with volunteer wheat in the combine straw swath, they may have germinated after being sprayed with glyphosate in the fall.

Weed ID – by Brittney Littlefield, Fieldwalker Agronomy Intern

Bird’s Eye Speedwell

In its early stages Bird's Eye Speedwell can be mistaken as Mouse-Eared Chickweed. This misidentification is due to both having creeping habit and reddish-brown coloured stems. At early stages, Bird's Eye Speedwell identifiers include opposite, rounded leaves with toothed margins closer to the bottom of the stem and alternate leaves, with leaf bunching at the growing point. This leaf orientation differs from Mouse-Eared Chickweed, which has small, entire margined and rounded oval leaves. At the mature stage, Bird's Eye Speedwell may be identifiable by its purple flowers.

Herbicide Application Timing Terms

A quick review of various the terminology;

Burndown – spraying green foliage prior to tillage or planting, typically with glyphosate.

Pre-Plant Incorporate (PPI) – a residual soil applied herbicide that is worked into the soil 2-3”.

Pre-Plant (PP) – a residual soil applied herbicide applied prior to planting but is not worked into the soil.

Pre-Emerge (PRE) – a residual soil applied herbicide applied after planting, but prior to crop emergence.

Early Post-Emergence (EP) – a contact/residual herbicide applied after crop emergence, typically 1 to 3 mature leaves.

Late Post-Emergence (LP) – a contact/residual herbicide applied after crop emergence, typically 5 to 8 mature leaves.

Pre-Harvest (PH) – applied to a mature crop prior to harvest to improve harvestability or to control perennial weeds.

Post-Harvest – a herbicide applied following harvest (3-4 weeks typically), to control annual or perennial weeds. Tillage may or may not occur following application.

Cover Crop Oats and Winter Annuals

One observation from a no-till alfalfa field. Fall winterkilled Oats suppress winter annuals much better than low seed rate Italian Ryegrass. See pictures below.

When is wheat too big to use floater tires?

Once wheat starts into stem elongation or jointing, my rule of thumb has been 1st node is the cut off for running with floater tires. There is not reason in a year like 2021 to be using floater tires on big wheat at 1st or 2nd node (dry soils for the most part, can carry skinny sprayer tires), when the majority of the province has had relatively dry conditions. What happens if you do run on really big wheat? Biggest difference I have seen, depending on the soil conditions and time of day the application is made, is uneven heading date on the tramped areas. If you do need to run with floaters (i.e., spreading manure or only available machine), running in the middle of the day will reduce the amount of injury, when the stem is more pliable.

Question - When should I apply my second pass of nitrogen on my wheat?

Answer - If you have corn or soybeans to plant, I would be applying my 2nd pass of nitrogen on the wheat. Many readers may already have. Do not let getting the “absolute” perfect day of applying nitrogen on wheat hold you up from getting $7ish corn and $17ish soybeans in the ground.

Three Possible Types of Fleabane

When scouting fields, it is important to mark which ones have fleabane, as Canada Fleabane can become a significant problem in 3 years. However, there are two other biotypes that are common in Ontario that are not glyphosate resistant. These are Annual and Philadelphia fleabane. If you are still getting good control of fleabane with glyphosate, it could be one of these other biotypes. The Ontario Weed ID Guide for Field Crops provides a few clues on how to tell the differences. The guide is available at this link; https://fieldcropnews.com/2016/09/weed-id-guide-for-ontario-crops/

1. Canada Fleabane - Canada fleabane has narrower and darker green leaves with margins that are generally less toothy. Annual fleabane has larger and broader leaves and showy “daisy-like” flowers.
2. Annual/Rough Fleabane - The leaves of annual or rough fleabane are much broader, more coarsely toothed and are usually lighter green. The flowers of annual or rough fleabane are much different than Canada fleabane, resembling a daisy flower, although much smaller.

1. Philadelphia Fleabane - The flower heads of Philadelphia fleabane are like annual fleabane in shape and size but are usually pink to purple in colour. Its upper leaves are broader and strongly clasp the stem.

Soybean Burndown Options

In most cases the rate will be based on the largest perennial in the field. Any newly germinated weeds will be controlled by the herbicide or rate selected for the perennial weeds. There are a few exceptions. 1) If you have glyphosate resistant summer annuals such as, Giant Ragweed, or Waterhemp, scouting will be critical to proper timing, and a tank-mix partner that controls the respective weed, 2) spring germinated Canada Fleabane, which should be assumed to be glyphosate resistant, will require a tank-mix partner with the glyphosate.

Glyphosate Rate Equivalency and Effective Rate

Many manufacturers are now running 540 grams active/L of product. The bigger question is, what rate should I be using control the respective weed?

If you don’t have a seed monitor or want to check your monitor this chart may help

What is your favourite nozzle for applying liquid fertilizer to Winter Wheat?

Most of my application experience has been with dry fertilizer on Winter Wheat. However, the day the deal closed on the used field sprayer Chafer bars were ordered to be able to apply UAN on winter wheat. If you prefer to not use Chafer bars (they have to be put on and off (cannot use your triplets, and can be flimsy), pick the nozzle that would have the least amount of leaf burn, but the most amount coverage (to account for boom height variation), usually a 5-hole fits the bill, for those running 20” spacing. A three hole is overly sensitive to heigh variation, and a 7- hole results in higher amounts of leaf burn. If you are running 15” nozzle spacing, you may get away with a three hole. I have also had good luck using Chafter bars for applying UAN in corn up to the 6-leaf stage with minimal burn (do not applying when a dew is on the plants). Phil Needham of Needham Ag suggests that you will gain about 2-3 bushels on 100 bu/ac wheat using Chafer bars (Phil imports Chafers bars into North America from Europe). In Canada you can purchase them from Argis 2000 in Listowel, ON. https://youtu.be/VXnXLThg4wA

“A busy schedule hides the inability to prioritize.”

– Shane Parrish