Growth Stage and Herbicide Application

mca2022dev on June 7, 2021

Herbicide applications are well-underway in corn, including tank-mixes. Fields should always be scouted before any herbicide application for weeds present, precise crop staging and environmental conditions that could have an affect on efficacy.

Applying a herbicide at early growth stages provides greater crop safety, in most cases. The corn plant has a smaller surface area to be in contact with the herbicide, which means a smaller risk of damage. Herbicides with active ingredients like 2,4-D or dicamba can need to be applied to the crop as early as possible for this reason: the larger the crop, the greater the plant surface area and the greater the risk to the crop. It is very important to refer to all herbicide labels and contact appropriate companies with any questions prior to applications.

Refer to Manitoba Crop Alliance’s Vegetative Growth Stage ID factsheet for staging tips.

Also available is a Quick Herbicide Reference Guide for current pre-emergent and post-emergent herbicides on the market in Manitoba.

Quick Herb Ref Guide

Post-emergent herbicide application tips: (for full list, visit https://www.dekalbasgrowdeltap…)

  • ALWAYS READ AND FOLLOW LABEL DIRECTIONS.
  • Corn under stress may not have the ability to metabolize some herbicides quickly enough to avoid crop injury. Weeds under stress may not may not accept the herbicide to its full capacity.
  • Spray additives can increase the rate of herbicide uptake by the crop.
  • Herbicide residues from previous applications may remain in the spray tank causing contamination.
  • Post-emergent herbicide injury symptoms can include leaf chlorosis or necrosis, onion leafing, internode stacking, rat tailing, ear pinching, ear bottlenecking, brace root malformation, and green snap.

Reference: https://www.dekalbasgrowdeltap…

Flax: Emergence and Frost

mca2022dev on May 26, 2021

Frost Impact on Flax

Flax plants just emerging (cotyledon stage) are the most susceptible to early spring frost, but can withstand temperatures down to approximately -3° Celsius. After the seedlings have passed the two leaf stage and are hardened by exposure, they can withstand temperatures as low as -8°C for a short time, without significant damage (https://flaxcouncil.ca/growing…).

Flax is generally at the first whorl stage right now, so a hard frost can have significant damage on the crop. It is important to follow the typical frost scouting techniques and wait 3-5 days to see whether frost has impacted the crop or not.

Emergence Monitoring (posted by SaskFlax: https://www.saskflax.com/quadr…)

One way to work towards optimizing flax performance on your farm is to determine the plant population and calculate emergence rate. Relating these numbers back to the seeding rate used, the environmental conditions and other factors at seeding can help determine management practices for the growing season and adjustments that can be made next year.

Steps to determine actual plant population and emergence rate:

1. At 1.5 to 2 weeks after seeding, count the number of plants per square metre or foot in a few representative locations in the field and calculate the average. This number is the plant population. To maximize yield potential, the minimum desired population for flax is 300 plants/m2 (28 plants/ft2) and the maximum is 400 plants/m2 (37 plants/ft2).

READ MORE at SaskFlax’s May 2021 edition of Flax on the Farm

Sunflower Frost Tolerance

mca2022dev on May 26, 2021

Frost Tolerance

Sunflowers are fairly frost tolerant up to the V4 or 4 leaf stage. The cotyledons just emerging are most frost tolerant, with risk of injury increasing as the plant adds leaves. If sunflowers become brown or black and the terminal bud is severely damaged, plants will not recover. Less severe frost damage may result in loss of apical dominance and plants will exhibit branching from axillary buds, resulting in multiple heads later in the season.

Tolerance to frost in sunflowers can be influenced by the hardening off process. If it is cool or cold for several days previous to the frost, seedlings may have better tolerance to lower temperatures. (https://www.gov.mb.ca/agricult…)

Plant Population

As the crop appears to be fully emerged in the late VE staging, it is a great time to do population counts to determine planting accuracy. Not all sunflower plants may have emerged at this stage, which makes timing appropriate. If the majority of the crop has emerged, a producer should be assessing what percent of the crop remains below the soil surface and why they are behind the rest of the crop. Dry soil, poor seed to soil contact, and consistent planting depth were all planting issues that have to be contended with in extremely dry planting conditions. Go out to the field and do some plant counts now to determine what may have gone wrong just a few weeks ago. Assessing a planting situation at harvest is not the time to learn from mistakes or environmental challenges.

To estimate plant population of emerged crop, determine the length of 1/1,000th acre using the table below (http://corn.agronomy.wisc.edu/AA/A033.aspx). Measure that distance out and count how many plants have emerged. Record the number. Repeat this 10 times at random locations to get an estimated average of final plant population.

1 1000th acre

This is also the ideal time to be scouting for cutworms. John Gavloski, provincial entomologist with MARD, suggests scouting to make sure some cutworms are present before applying an insecticide. This time of year there can be a lot of natural enemies emerging. One John sometimes finds in high numbers early in the season is a small ground beetle called Bembidion, that can be very good at keeping levels of some other insects down. John warns that it would uneconomical to take out populations like these if the cutworm population was low. The take home message with early cutworm control is to always scout before applying an insecticide and avoid the proactive insecticide application.

Dingy cutworm MC

Corn Emergence – Early Concerns

mca2022dev on May 25, 2021

SPRING FROST:

Late May consistently brings early frost concerns in all crops. Corn is quite tolerant of temperatures below freezing because the growing point remains below ground until V6 approaches, however, if air temperatures dip below -2oC for more than a few hours, it is possible for the growing point to be damaged. See Is Corn Susceptible to Spring Frosts for temperature and scouting details following a spring frost event.

COLD BANDING:

Due to typical warming, followed by cooling spring temperatures as the corn crop was emerging, at VE and V1 staging it is possible to see cold banding on seedlings. As elongation occurs below the soil surface during warm conditions, a period of chilling can create a few growth issues. Most common is imbibitional chilling injury, which is the twisting or corkscrewing of corn mesocotyl as it is trying to emerge. This is when seed has imbibed (absorbed) the water required for germination and then the soil cools to temperatures below 10oC for prolonged periods. Cold banding is when air temperatures drop to 5 – 10oC and plants close to the soil surface get a yellow band across the leaf tissue. This is not cause for concern, but a common site at this time of year when temperatures bounce around.

3

PLANT POPULATION:

As the crop appears to be fully emerged in the late VE staging, it is a great time to do population counts to determine planting accuracy. Not all corn plants may have emerged at this stage, which makes timing appropriate. If the majority of the crop has emerged, a producer should be assessing what percent of the crop remains below the soil surface and why they are behind the rest of the crop. Dry soil, poor seed to soil contact, and consistent planting depth were all planting issues that have to be contended with in extremely dry planting conditions. Go out to the field and do some plant counts now to determine what may have gone wrong just a few weeks ago. Assessing a planting situation at harvest is not the time to learn from mistakes or environmental challenges.

To estimate plant population of emerged crop, determine the length of 1/1,000th acre using the table below (http://corn.agronomy.wisc.edu/AA/A033.aspx). Measure that distance out and count how many plants have emerged. Record the number. Repeat this 10 times at random locations to get an estimated average of final plant population.

1 1000th acre

WEED CONTROL:

The first in-crop herbicide applications can occur at VE in glyphosate-tolerant corn. Due to the dry conditions prior to May long weekend, weed emergence was slow. Following varying rainfalls, weeds will likely be germinating quickly now, so it will be important to stay ahead of weed pressure. See MCA’s Quick Herbicide Reference Guide to see what can be applied and when for certain weed spectrums. It is always recommended to refer to the herbicide label for complete information or Manitoba’s Guide to Field Crop Protection prior to all applications.

Quick Herb Ref Guide

Manitoba Crop Alliance and University of Manitoba advancing Canadian agriculture through new research facility

mca2022dev on May 11, 2021

FOR IMMEDIATE RELEASE

Tuesday, May 11, 2021 (Carman, MB) – Manitoba Crop Alliance (MCA) is contributing $500,000 to the University of Manitoba (UM) towards the building of the Prairie Crops & Soil Research Facility (PCSRF). The PCSRF will further strengthen the UM’s already well-recognized agronomy and crop production teaching and research programs. Construction of the new facility will begin next year.

“I thank our research collaborators at MCA for their leadership and vision in the support of the new PCSRF, one of the Faculty’s most significant renewal strategies for research in crop production. This gift represents investment in agricultural research by Manitoba’s farmers that will foster the development of integrated and resilient agronomic systems to the benefit of Western Canadian producers,” says Dr. Martin Scanlon, Dean, Faculty of Agricultural and Food Sciences, UM.

The PCSRF will increase the capacity for crop research and allow scientists to better integrate soils, crop, entomology and livestock research to make crop production in Manitoba more sustainable. Farmers in Manitoba will benefit from research topics including agronomic and cropping systems for optimized performance and longer-term sustainability, weed management, advanced crop protection, new cultivars and crops, profitability of nutrient strategies, and carbon benefits of crop production practices.

“MCA wishes to express our gratitude for the UM’s continued commitment to the improvement of facilities and equipment that are so essential for advanced modern research and the training of highly qualified personnel,” says Fred Greig, Chair of MCA. “We anticipate this expansion and modernization of research capacity at the UM will accelerate the growth and health of our industry by putting innovative solutions in the hands of our farmer members.”

MCA values the partnership with the UM and are currently supporting 30 projects totaling approximately $500,000 per annum. MCA will continue to work together with the UM to address research priorities and communicate research results to our members.

For more information about MCA research investments, please visit mbcropalliance.ca/research/projects. For more information about the UM, please visit https://umanitoba.ca/agricultural-food-sciences/.

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About Manitoba Crop Alliance:
Manitoba Crop Alliance is a non-profit organization established August 1, 2020 representing over 9,000 farmer-members. Manitoba Crop Alliance puts their farmer-members first and strives to continuously improve the competitiveness and profitability of all crops represented by the organization by focusing on four main areas: research, agronomy, market access and development, and communications. It is through investment in these key areas that Manitoba Crop Alliance can ensure wheat, barley, corn, sunflower and flax are sustainable production choices for Manitoba farmers. For more information, visit mbcropalliance.ca.

About University of Manitoba:
The University of Manitoba is home to a community of more than 29,000 students, 5,000 academic staff and 3,900 support staff. Recognized as Western Canada’s first university and located in the city of Winnipeg, the University is committed to advancing Indigenous research and achievement, recognizing the significant contributions of Indigenous peoples in Canada. UM is one of the U15, ranking among Canada’s top research-intensive universities and is Manitoba’s only medical-doctoral post-secondary institution. Providing high-quality liberal arts, science and professional programs of study, the University inspires undergraduate and graduate students to positively impact their communities as globally-engaged citizens.

 

For more information, please contact:

Pam de Rocquigny

Chief Executive Officer

Manitoba Crop Alliance

204.745.6661 | pam@mbcropalliance.ca

Brooke Karlaftis

Donor Relations

University of Manitoba

204-474-7835 | Brooke.Karlaftis@umanitoba.ca

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