Agronomy & Extension – Special Crops Archives

Sign up now for our 2026 Corn Yield Competition

Coles Ag on October 6, 2026

Manitoba Crop Alliance (MCA) is looking for participants for the 2026 Corn Yield Competition! All entrants must be farmer members of MCA.

This year’s competition will be the last in its current form. We would like to thank all our farmer members who have participated during the competition’s 55-year history. Your efforts to strive for bigger and better yields year after year have inspired us and we hope you continue to push those boundaries. Stay tuned, as we have something new in the works that will help farmers continue the quest for corn yield improvement in 2027 and beyond.

Prizes will be awarded as follows at MCA’s 2027 Annual General Meeting, which will be held on Feb. 11 during the CropConnect Conference:

1^st Prize – $1,000 and a wall plaque (sponsored by the company with the winning hybrid)
2^nd Prize – $500 and a wall plaque
3^rd Prize – $300 and a wall plaque
4^th and 5^th Prize – Receive a wall plaque

Instructions for entering the yield competition

Please review the instructions and keep them in mind as you are scouting for the very best spot in your field. Even if you don’t have your spot(s) picked out, you can still enter early!

For more information or to enter, please contact:

Morgan Cott
Agronomy Extension Specialist – Special Crops
Manitoba Crop Alliance
204-750-2489
morgan@mbcropalliance.ca

CDC Triffid Testing Protocols Terminated

Morgan Cott on May 4, 2026

Manitoba Crop Alliance (MCA) works closely with industry partners to build relationships and collaborative opportunities. Through these industry relationships and discussions with farmer members, MCA has prioritized the importance of eliminating the CDC Triffid testing protocol on Canadian flax being exported into the EU, which has been in place since 2009. It has been over 13 years since CDC Triffid has been identified in any Canadian shipments destined for the EU. The termination of the testing protocol is great news for Canadian flax farmers and exporters and will hopefully lead to improved international trade of Canadian flax.

Read Agriculture and Agri-Food Canada’s full news release here: Removal of non-tariff trade barrier for flaxseed to the EU reflects confidence in Canada’s agricultural exports.

Making Every Pound Count: Nutrient Management in Corn

Morgan Cott on April 8, 2026

Fertility starts with the soil and the variables that make nutrients available to a growing crop.

Know Your Soil Texture

Clay – very fine, soils with >50% clay
Silt – rock & mineral particles that are larger than clay and smaller than sand. Soils with >87% silt
Sand – very coarse, soils with >70% sand
Loam – a balanced mixture of clay, silt and sand (approximately 20-40-40)

Soil Texture Triangle

Soil texture determines a soil’s water holding capacity. Sand has low capacity to hold water and low water content at permanent wilting point (~10-15% v/v). Clay loam has a higher capacity to hold water, therefore has a higher water content at permanent wilting point (~15-20% v/v).

Relationship bw soil texture and water availability

Relationship Between Soil Texture and Water Availability

Nutrient Balance

Nutrient balance is vital to soil fertility and crop production. Nitrogen is most commonly the first and most limiting nutrient for non-legume crops, but without an adequate fertility blend with other nutrients, nitrogen use efficiency is not “maxed out” and suffers.

A poorly fertilized corn crop uses just a little less soil water over the season than an adequately fertilized crop, and yet fewer bushels of corn are produced per inch of water used. The properly fertilized crop is able to be much more efficient in water usage to produce more grain per inch of water used.

Nutrient Uptake

Nutrient movement in the soil and uptake by plant roots is important to understand because it dictates where fertilizer placement best facilitates root uptake. Nitrogen and sulfur are very mobile in the soil and move via mass flow. This essentially means that they move with the soil water. As a plant transpires water, the roots are required to draw in more nutrient-rich soil water and they do this by creating tension that draws the soil water to the roots. The rate of transpiration is related to environmental conditions, so poor soil moisture or cold temperatures, for example, will decrease the rate of transpiration, therefore decrease uptake of soil water (and nutrients) via mass flow. Phosphorus and potassium move in the soil via diffusion, meaning that with the help of soil moisture, the nutrients move from areas of high P or K concentration to areas of lower P or K concentration. As the nutrients are absorbed by plant roots and moved up into the plant, the roots become an area of low concentration, thereby drawing nutrients towards the roots from a higher concentration zone.

Nutrient Mass Flow & Diffusion

Nitrogen

Exact nitrogen rates in corn are still hard to identify and perfect. Modern corn hybrids have improved in nitrogen use efficiency, but more than that is required to optimize nitrogen uptake. We have already discussed how nutrient balance in the soil optimizes nutrient uptake, but soil conditions and the environment above and below the ground play major roles in this as well.

In 2016-17, John Heard, former Manitoba Agriculture Soil Fertility Specialist, performed a nitrogen use and uptake project in corn to identify whether nitrogen recommendations needed to be updated. Following this project, Dr. Don Flaten’s graduate student, Lanny Gardiner, then began his Master’s research, in 2018, on a similar study, “Optimum Nitrogen Fertilizer Management Strategies for Modern Corn Hybrids in Manitoba”. The two studies complemented each other with similar findings, which were the following:

Nitrogen requirement to achieve the economically optimum yield for higher and lower potential yields. John Heard, 2022 – Profitable Nitrogen Rates.

A site that has a “lower” potential yield would be one that could be considered to have poor productivity. This may include variables like drainage issues, salinity, soil productivity, or poor crop management choices like delayed seeding, compaction issues, or delayed weed control, for example.

Dry sites in 2018-19 needed more nitrogen to achieve similar yields because dry soils have less mineralization of soil organic matter and decreased mass flow movement of nitrate-N to the plant root.

Phosphorus

Phosphorus is required for plant growth and seed development, therefore should be placed at least in a sideband for availability in early growth. It is not very mobile in the soil and will not get leached in spring conditions like we know nitrogen will in high moisture.

The general recommendation for phosphorus requirements in corn is +0.6 lbs of P per bushel of yield. Uptake is equivalent to 0.6 lbs P/bu and removal is 0.36 lbs P/bu, so it is very important to consider what your preferred level of phosphorus in the soil is following a corn crop.

Applying phosphorus at planting is the best practice for availability. The safest placement is in a 2×2 band but proceed with caution if applying P in a sideband with other nutrients. P is used throughout the season and some farmers choose to apply additional P in-crop, which can be a good practice but not studied thoroughly in Manitoba to come to an economical conclusion.

Potassium

Corn requires 1.28 lbs K per bushel, but will only remove 0.21 lbs K/bu. In a 150 bushel crop, uptake will be about 192 lbs of potassium and removal will be 32 lbs of potassium because so much of the nutrient stays in the vegetative tissues. Manitoba soils are generally high in potassium, but it is important to monitor and fertilize to maintain K supply in the soil.

To support a corn crop, ensure there is greater than 200 ppm of K in the soil. When levels start appearing in the 100’s, farmers may see benefits from adding K at this time. Livestock farmers may find a significant benefit from applying manure in this situation.

If potassium becomes deficient, the plant will pull the nutrient from older leaves to feed the younger leaves, developing grain, etc., just like nitrogen, and that is when deficiency symptoms appear.

Sulfur

Sulfur is not needed in high quantities like our other three macros, but it is required for corn development and chlorophyll production, therefore photosynthesis.

Corn does not necessarily respond to additional sulfur fertilizer, unless soils are already deficient, whereby a yield response will occur with fertilization. Farmers should be aware of sulfur levels in the soil and be prepared to apply sulfur when levels decline. Sulphate sources are typically available to the crop immediately, so timing of application can be flexible. If deficiency symptoms appear (interveinal striping), rescue applications can be effectively made.

Additional Resources on Corn Fertilization:

Spring Nitrogen Application Options – Manitoba Crop Alliance
Profitable Nitrogen Rates for Corn – Manitoba Agriculture
Corn – Soil, Nutrition and Fertilizers – Manitoba Agriculture
Nitrogen for Manitoba Corn: Rates and Splits – Manitoba Agriculture

2025 Sunflower Crop Survey Results

Morgan Cott on March 3, 2026

The Sunflower Crop Survey is led by the National Sunflower Association and carried out by a network of volunteer from universities, government, producers and industry, including Manitoba Crop Alliance (MCA). Participating regions include Manitoba, North Dakota, South Dakota, Minnesota, Nebraska, Kansas, and Colorado, where data is collected on a number of variables and compiled to document sunflower growing conditions, pest challenges and yield. The survey is conducted on alternate years, with fall 2025 being the most recent.

Manitoba and U.S. Survey Overview:

191 Sunflower fields were samples across all participating regions. The following management practices were observed:

Sunflower type: 7% confection; 93% oilseed
Water Management: 2% irrigated; 98% dryland
Tillage: 24% conventional; 21% minimum; 55% no-till

The survey has a large focus on pest pressures. The cumulative pests that were monitored across all locations were as follows:

34% of fields had blackbird damage
11% of fields had seed maggot damage
8% of fields had bud moth damage
8% of fields had sunflower midge damage
14% of fields had long-horned beetle damage. It is important to note that long-horned beetle has not been found in Manitoba during this survey, or in anecdotal scouting events, however there are fields sampled in this survey that are extremely close to the MB-ND border that had long-horned beetle (dectes) damage in both 2025 and 2023.

Manitoba Overview:

12 sunflower fields in 10 municipalities were sampled in Manitoba from the RM of Brokenhead to the RM of Two Borders:

Sunflower type: 100% oilseed
Water Management: 100% dryland
Tillage: 25% conventional; 67% minimum; 8% no-till
Row Spacing: 50% had 20” or narrower row spacing, 50% had 22” to 30” row spacing

Each field was surveyed in two locations and a small sample area of two rows by 25 feet was used to gather data in each of the two locations. Pests were recorded, full plants were assessed, and seed samples were taken.

The highest yield in a sampled area was 2,792 lb/ac.

The lowest yield in a sampled area was 983 lb/ac.

The average yield among all 12 fields sampled was 2,000 lb/ac.

Yield-Limiting Factors

Seven of the 12 fields were limited mainly by disease, in general.
One of the 12 fields was limited mainly by bird presence and feeding.
One of the 12 fields was limited mainly by row spacing, as it was a solid-seeded field. This was hard to measure yield on such a small scale with fewer plants per foot of row.
Three of the 12 fields were limited mainly by weed pressure, with one of them being specifically limited by kochia infestation. In the 12 fields, weed pressure was generally quite low and not at all a concern in 75% of the fields.
Secondary limitations in the 12 fields sampled included wildlife (i.e., elk), lodging, insect, sclerotinia and birds.

Disease Presence and Severity

Sclerotinia:

Sclerotinia basal stem rot was minor in all fields sampled. Half of the fields had no basal wilt present. One field had up to eight plants with basal wilt symptoms, which would be estimated at about 8% of the sample size in that field.
Sclerotinia mid-stalk rot presence was similar to basal stem rot. Eight fields had zero or just one plant infected; one field had six infections and another had seven infections; two fields had 10 or 12 plants infected, respectively.
Sclerotinia head rot were higher, in general. Half of the fields had four or less infected heads; three fields had 5-7 infected heads, one field had 10 infected heads, one field had 12 infected heads and one field had 22 infected heads. This last field did report the lowest yield as well, unsurprisingly.

Downy Mildew:

Low incidence among all fields, except one that had four affected plants

Phomopsis:

Six of the 12 fields had almost negligible one or zero plants with Phomopsis infections.
Five of the 12 fields had from six to 15 stalks infected with Phomopsis.
One field had 40 plants with Phomopsis infections, which was roughly 80% incidence in that location.

Phoma:

Incidence was much higher and present in relatively high numbers in each of the 12 fields, except for two that had zero incidence.
The three highest fields of incidence had 32, 42 and 46 plants with Phoma stem infections.

Rhizopus:

Rhizopus has not been a disease of concern in Manitoba, simply because it can largely go undetected. The last time the sunflower survey was conducted, in 2023, three of eight fields had Rhizopus in the sample set.

Rhizopus can be identified on a sunflower head by the presence of gray, fuzzy mycelium, usually viewed on the face and between developed seeds. The disease prefers warm, humid environments and most often originates via wounds on the back of the sunflower head. Infections do affect yield by limiting seed fill and potentially causing head drop in severe cases.

Rhizopus on sunflower head. Photo courtesy of North Dakota State University.

Sunflower Rust:

Sunflower rust was very minimal in 2025 and was found in four of the 12 fields at very minor severity in September. The highest severity was one field that exhibited 0.75% of leaf area on the top four leaves being affected by rust pustules.

Verticillium Wilt:

Verticillium wilt is also uncommon in sunflower fields in Manitoba, though it was found in the 2025 survey. Symptoms can include leaf mottle, or interveinal chlorosis, and a greenish discolouration on the stem, where further inspection is required. By splitting the stem at the base of the plant, discoloured vascular tissue is visible around the pith.

Three fields were found to have Verticillium wilt with five, six and 12 plants infected, respectively.

Insect Presence and Severity

Sunflower Midge:

Seven of the 12 fields had Sunflower Midge damage.
The field with the greatest damage had seven affected heads.

Sunflower Seed Maggot:

Three of 12 fields had Sunflower Seed Maggot damage.
Each of the three fields had one plant affected.

Sunflower Bud Moth:

Nine of 12 fields had Sunflower Bud Moth damage, specifically on the sunflower head.
The field with the greatest damage had 14 affected heads, followed by a field that had 10 affected heads.
The remaining seven fields had minor damage noted.

Blackbird Presence and Severity

Blackbird feeding was noted in five of the 12 fields sampled. Assessment is based on the area of the sunflower head with missing seed that has recognizably been fed on by birds. Seed is usually completely missing and sunflower seed shells may be found on or near the plant in question.

All four fields with damage noted were quite minor in the sampled areas, the greatest having about 6.35% of the total head area missing seed.

Other Yield Factors

Actual plant populations of sampled fields ranged from 12,200 to 24,400 plants per acre. Strangely enough, the lowest populated field also had the smallest head size, averaging about 5.75” in diameter. The field with largest head size overall was 8.45” diameter. Generally, head size was smaller in the sampled fields than an average year would see, but this may have been a result of dry growing conditions during head development.

Seed size was reported to be good to excellent and seed fill ranged from 70 – 99% across the 12 fields. Centre seed set was reasonable, but there were some fields that did have up to two inches of the head centre undeveloped, which drastically affects yield.

MCA would like to thank all 12 participants of the Sunflower Survey for allowing us to use your fields for this project. Also, thank you to Manitoba Agriculture oilseeds specialist Sonia Wilson and crop production extension specialist Callum Morrison for your help surveying several fields. Finally, thank you to Dr. Ahmed Abdelmagid, research scientist and oilseed pathologist at AAFC Morden, for surveying several fields and collecting various samples of sunflower diseases to understand the scope of disease presence in Manitoba.

2025 Manitoba Corn Disease Survey Results

Morgan Cott on January 30, 2026

Anne Kirk, Manitoba Agriculture
Morgan Cott, Manitoba Crop Alliance
Simon Huang, Manitoba Agriculture

A corn disease survey was conducted across Manitoba in September of 2025. Crop disease surveys are important for documenting the severity and geographical distribution of various diseases. Results from disease surveys provide warning about new diseases and help to prioritize where future research is needed.

Methods

A total of 54 fields were surveyed across Manitoba to document the prevalence (% of fields having infection) and incidence (average % of plants showing infection within infected fields) of various corn diseases. Field were surveyed in September around the beginning of crop maturity.

Plants were visually assessed for the presence of Goss’s wilt (Clavibacter michiganensis subsp. nebraskensis), common rust (Puccinia sorghi), common smut (Ustilago maydis), head smut (Sphacelotheca reiliana), and stalk rot. Holcus spot (Pseudomonas syringae pv. syringae) was recorded in some but not all fields. In each field, 50 plants were surveyed in a “W” pattern, where the five points of the “W” were at least 50 paces apart and 100 m from field edges. The presence or absence of disease was noted for each of the 50 sampled plants per field, except for Goss’s wilt and holcus spot. Goss’s wilt and holcus spot were simply recorded as present or absent for each field.

Results
At crop maturity Goss’s wilt was found in 54% of the fields sampled, making it the most common disease found in the fall survey. Holcus spot was found in the majority of fields surveyed in the central region, but prevalence is not reported as all surveyors were not assessing plants for holcus spot. Head smut, common rust, stalk rot, and common smut were found in 33%, 11%, 7% and 6% of fields surveyed, respectively (Table 1).

Table 1. Results of the 2025 corn disease survey. Prevalence (% of fields having infection) and incidence (average % of plant showing infection within infected fields) for each region and for all fields surveyed.

Region	Common Rust	Common Smut	Head Smut	Stalk Rot	Anthracnose Stalk Rot	Goss’s Wilt
Central (35 fields)
% Prevalence	14	9	29	6	0	71
% Incidence	17	8	3	13	0	n/a
Eastern (9 fields)
% Prevalence	0	0	22	11	0	44
% Incidence	0	0	8	2	0	n/a
Interlake (2 fields)
% Prevalence	50	0	0	50	0	0
% Incidence	10	0	0	6	0	n/a
Southwest (8 fields)
% Prevalence	0	0	75	0	0	0
% Incidence	0	0	5	0	0	n/a
Manitoba (54 fields)
% Prevalence	11	6	33	7	0	54
% Incidence	16	8	4	9	0	n/a

Acknowledgements
This survey was supported by Manitoba Agriculture and Manitoba Crop Alliance. Thank you to the grower co-operators who allowed for their fields to be surveyed and provided surveyors with field information.

Contributed by Anne Kirk, Cereal Crop Specialist with Manitoba Agriculture.

Flax Diseases: A 2025 Overview

Coles Ag on October 1, 2025

Crop disease surveys are performed for several reasons. MCA looks to this project as being useful for extension purposes, as well as providing data to support research priorities in Manitoba.

The disease survey is conducted each August – September, depending on maturity. Eight to ten fields are scouted, primarily for pasmo incidence and severity, but also for Alternaria, aster yellows, fusarium, powdery mildew, rust and sclerotinia. These are all uncommon in Manitoba, and considering only 100 plants are being rated for the above diseases, it is rare to have incidence of anything other than pasmo and aster yellows reported. The last time aster yellows were reported in the flax disease survey was 2023, when incidence was relatively high in a small number of tested fields. Since then, there has been low incidence but it can still be found on the odd plant. Mainly because it is easy to identify and the infected plants stick out among “normal” plants.

In the 2025 flax disease survey, 10 fields were surveilled, which equivalates to one field for every approximately 2,800 acres of flax. For larger acreage commodities, there would typically be one field surveyed for every 5,000 acres in a Rural Municipality.

Due to dry weather conditions in 2025, disease incidence was very low to zero for every pathogen looked at. In fact, only three of the 10 fields scouted showed signs of pasmo in the 100 sampled plants. In those three fields, incidence was 10%, 14% and 2%, which is to say that only 10, 14 and two plants in the 100 plants sampled in each field had pasmo present. Severity refers to the total area on the plant that is infected with pasmo, expressed as a percentage. In the three fields with pasmo present, severity ranged from 1% to 30% on the plants affected. Overall, incidence and severity were both lower than normal; likely an effect of dry conditions early in the season. Pasmo, like several other pathogens, spreads rapidly in high temperature, damp conditions.

Pasmo is a fungus that attacks above-ground parts of flax and overwinters in the soil on infected flax stubble. Flax is most susceptible to pasmo in the ripening stage. Pasmo can cause defoliation, premature ripening and can weaken the infected pedicels resulting in heavy boll-drop by rain and wind. Depending on the earliness and severity of the infection, pasmo reduces the yield as well as the quality of seed and fibre. Most commercial varieties lack resistance to this fungus. Pasmo is characterized by circular and brown lesions on the leaves and by brown to black infected bands that alternate with green and healthy bands on the stem. The best control is achieved by early seeding at the recommended rates to avoid high moisture conditions in the fall, using clean seed, treating seed with a fungicide, controlling weeds, and following a rotation of at least three years between flax crops.

Pasmo-infected flax stalk.

Aster Yellows is a very random disease, infecting plants that have been fed on by aster leafhoppers that are specifically infected by the aster yellow phytoplasma. Aster yellows affect many different crops, with canola being the most economically significant in Manitoba. Aster leafhoppers are sucking insects that transmit aster yellow phytoplasma directly into the phloem of a healthy flax plant, thereby infecting that plant. Damage is evident in misshapen or unproductive bolls.

Flax aster yellows.

In preparation for the 2026 flax crop, farmers will want to follow some key tips for disease prevention:

Use clean seed
Diversify crop rotation
Use seed treatments
Keep fields weed-free

For more information on:

Emergency Use Registration: Avian Control For Use as Blackbird Deterrent in Sunflower

Morgan Cott on September 2, 2025

Manitoba Agriculture, Manitoba Crop Alliance and Avian Enterprises® are pleased to announce that Avian Control® Bird Repellent has been approved for use to deter blackbird feeding in sunflowers in Canada.

The need for a product used to deter blackbirds from feeding on sunflower crops has been identified as a need in Manitoba due to the significant losses recorded by farmers. Sunflower seeds are particularly vulnerable to predation by blackbirds due to the high nutritional value and easy accessibility.

After nesting, blackbirds form large flocks and begin feeding in grain fields nearby. Feeding begins in sunflowers soon after petal drop and most of the damage occurs during the following three weeks. Peak concentrations of blackbirds occur in mid-September, coinciding with the crop reaching physiological maturity.

Farmers have alternative options to applying a deterrent, like Avian Control ®. Alternate practices include planting far away from roosting areas, like cattail marshes and woodlots, or planting at the same time as neighbours to spread feeding damage over more acres during seed maturity. Insect and weed control will reduce the pre-season food source for blackbirds before the crop reaches a susceptible stage for feeding. Delaying cultivation or harrowing of crop stubble in neighbouring fields increases alternate feeding area for hungry birdlife. Desiccation to advance harvest and getting the crop harvested as soon as possible also reduces exposure.

Another effective management practice is to control cattail production areas, which reduces nesting sites for blackbirds. Managing cattails does take a significant amount of time and should be a collective project for local farmers to deter blackbirds from roosting in a large geographic area, to be effective. Scare methods, like bangers or sound devices, to frighten birds away from the area have achieved different levels of success, but birds tend to start tolerating certain tactics after a period and return to host crops.

How does Avian Control work?

The active ingredient in Avian Control is methyl anthranilate. This active irritates a bird’s trigeminal nerves, which are sensitive to smell and taste, and causes a temporary, non-harmful, but unpleasant sensation to the affected bird’s eyes, beak and throat. The first birds to visit the treated field associate this discomfort with that location and communicate this information to the rest of their flock, instructing them not to feed there.

Methyl anthranilate is a food-grade additive, naturally derived from Concord grapes. It is a non-toxic, non-lethal and humane repellent, recognized as safe for humans and other animals. Due to the nature of this product, it does breakdown on surfaces much quicker than pesticides and will likely need to be applied more than once for continued efficacy.

Crop Specific Instructions for Avian Control

Apply Avian Control to ripening sunflowers before damage by blackbirds begins to occur
Do not apply when crop is wet or rain is expected
Repeat treatment at 6 – 8 day intervals if significant crop damage from blackbirds begins to occur
Avian Control may be applied up to the day of harvest
Use with non-ionic surfactant at 0.06 – 0.25% v/v
DO NOT exceed 5 applications per year

For full Avian Control label on sunflowers, click here.

Please contact Avian Enterprises for more information on Avian Control and product orders:

Jon Stone
President, Avian Enterprises
1 (888) 707-4355
https://aviancontrolinc.com/products/avian-control/

Sunflower Survey 2025

Morgan Cott on June 30, 2025

In partnership with National Sunflower Association, every other year Manitoba Crop Alliance and Agriculture and Agri-Food Canada participate in a Sunflower Survey. The collaboration includes several states in the U.S. where sunflowers are grown, so participation in Manitoba is beneficial to the dataset.

Some of the factors included in the survey are:

Field analysis: population, head size, seed fill, yield calculations
Weed pressure: weed prevalence
Insect Pressure: insect incidence and damage severity
Disease Pressure: disease incidence and severity
Blackbird Presence: percent blackbird damage estimate
Other Limiting Factors: environmental, uneven growth, herbicide damage, plant spacing, and more.

Sunflower diseases make up the bulk of the survey since, agronomically, they are the greatest concern to the crop. The requirements are to assess ten diseases in incidence (number of plants) and severity (% damage to affected plants) of sunflower rust, specifically.

MCA is funding the participation of AAFC’s oilseed and Pulse Crop Pathologist, Dr. Ahmed Abdelmagid, on this project. Dr. Abdelmagid participates in the field survey and also analyzes stalk disease samples from each field to determine various strains present in Manitoba sunflowers.

This survey is important in a “minor” crop for Manitoba in order to help farmers understand the specific pressures they are working against. Together with AAFC and Manitoba Agriculture, we can use the survey data to create extension for farmers and agronomists that will strengthen the crop’s success on the Prairies. Paired with the U.S. data, we are able to make fair comparisons and and identify Manitoba’s successes and areas that need improvement. This leads to more directed research projects in the future and extension work with farmers on specific topics.

The 2025 Sunflower Survey will begin in late August. MCA is looking for several sunflower fields across the province to include. Please contact Morgan Cott at morgan@mbcropalliance.ca or 204-750-2489 if you or someone you know would like to be contact this summer to be involved in the survey. This tends to be a quick visit to collect data on all points mentioned above and the farmer will be kept informed throughout the short process.

Managing Bt Resistant European Corn Borer

Morgan Cott on April 3, 2025

European corn borer larvae

European corn borer (ECB) has long been a pest of Manitoba corn crops, but it is not only a nuisance to corn – crops like potatoes and hemp are affected as well. The larval stages of the insect are most economically significant due to their tunneling (boring) capabilities which disrupt the flow of nutrients and water, and the integrity of the stalk. Yields can certainly be affected by ECB presence, around 3-5% yield decrease being possible in standard incidences (5-9 bu/acre in a 175 bushel crop) and increasing in more significant infestations.

Until Bt (Bacillus thuringiensis) traits were introduced to corn in Canada and the United States in 1996, corn farmers would rely on cultural practices and insecticidal control when economic thresholds were met. Cultural practices include crop rotation, residue management – destroying stalks where larvae overwinter successfully, and tillage that buries residue deep enough that larvae cannot survive. Insecticidal control is difficult due to timing between egg hatch and the boring phase. Diligent scouting to monitor egg hatch progress is extremely important to time when most eggs have hatched and larvae have not begun entering the stalk tissue yet. Once larvae reach the 3^rd instar stage (7-10 days following hatch), they begin to bore into the stalk, and rarely resurface, rendering insecticide applications ineffective.

The introduction of Bt hybrids allowed farmers to not rely so heavily on residue management and insecticide application. Farmers were able to choose a fitting Bt-traited hybrid for their farm and had to match that hybrid with a refuge, or non-Bt, hybrid in 20% (or more) of the field in a block, strip or perimeter method. In more recent years, seed companies have come out with a 5% refuge system, called refuge-in-a-bag, making the system a lot easier for farmers to adhere to.

Unfortunately, non-compliance with pesticide requirements weakens the system and creates an opening for resistance. While the Bt trait is very strong, there is a small portion of the ECB population that are naturally resistant to the trait that controls the rest of the population. If farmers were to plant 100% Bt hybrids, those resistant populations would thrive and reproduce, eventually being the only population remaining.

BT CORN 101 – Manage Resistance Now

HOW RESISTANCE DEVELOPS – Manage Resistance Now

HOW TO MANAGE INSECT RESISTANCE IN YOUR BT CORN – Manage Resistance Now

MANAGING INSECT RESISTANCE VIA REFUGE PLANTING – Manage Resistance Now

Managing resistance on-farm can feel daunting, but it is very straightforward. Best management practices to avoid European corn borer resistance to Bt traits include:

Scout for pests and damage
Rotate crops and traits
Plant a refuge
Manage with insecticides
Keep accurate records

If there is a suspected case of ECB resistance in a Bt corn field, the following should be monitored to identify the issue:

Scout – both Bt and non-Bt corn for damage
Field Investigation – verify trait(s) present, evaluate presence and damage caused by ECB, rule out external reasons for damage
Contact Seed Company – seed company representative must be informed if ECB damage is found in Bt-traited crop, where it is determined the pest is resistant
Best Management Practices
Collect Insects – the seed company will likely arrange for live ECB samples to be taken from affected field(s)
Resistance Mitigation – if resistance is confirmed, farmer will be notified of next steps (see Managing Resistance in your Bt Corn)

Resources have been developed to help farmers, agronomists and seed companies identify issues in Bt corn fields as resistance incidents have occurred in Canada. Canadian Corn Pest Coalition is a group of industry members that work to develop extension and support to Canadian farmers and industry as insect issues arise. The CCPC has extensive resources available on their website on this specific topic, as well as other insect pests in corn. It is important for members of the corn industry to be educated on pest pressures that could turn into serious resistance incidents. Together we can improve the longevity of Bt traits so farmers can continue to use them safely and effectively.

Act Now ECB Campaign – Canadian Corn Pest Coalition

Contact your provincial Extension Entomologist (John Gavloski, Manitoba Agriculture) or MCA’s Agronomy Extension Specialist – Special Crops (Morgan Cott) for further information on European corn borer resistance, what to do to avoid it, and how to determine if you see possible resistance.

New, promising flax varieties for Manitobans

Morgan Cott on March 4, 2025

Manitoba flax farmers (and upcoming flax farmers) will soon have full access to a new flax variety, CDC Esme. As of spring 2025, CDC Esme is available to seed producers across the province, as long as they have been able to access it from seed dealers.

As stated in the Secan Technical Bulletin for the variety, CDC Esme is a large seeded, high yielding brown seeded flax variety with good lodging resistance and late maturity. Esme proves to be a strong yielder in MCVET trials across several site years, with oil content similar to check varieties. Statistics show an average of 2 cm shorter than CDC Glas, which is a beneficial trend in Manitoba, where farmers are trying to reduce flax straw and residue.

Dr. Bunyamin Tar’an and his team at the Crop Development Centre in Saskatoon developed CDC Esme and have several more flax lines that have strong potential for registration on the Canadian Prairies. Most recently, Tar’an had an experimental flax line that has been recommended for registration via Canadian Food Inspection Agency. This line, currently named FP 2608, will undergo a registration process and could likely be available for seed production in the next two years.

FP 2608 has been a promising yielder in the Flax Co-op trials performed in Manitoba and is a consistently strong yielder. It appears to be quite tolerant of pasmo infections in past reports, and oil content and yield has been ranked very high amongst other varieties and lines. Tar’an has noted that FP 2608 had considerably strong performance in the more northern Co-op trials in Manitoba, which perhaps displays its ability to thrive in less diverse rotations.

MCA is very proud of our relationship with Dr. Tar’an and are very excited about his future work in flax breeding. Some new work that he is working on includes “Accelerated Breeding Strategy for Flax Improvement” which looks at developing inbred populations in a shorter term than is current reality. This would mean that future varieties could potentially be brought to the market more quickly and readily than they have in the past. Another highlight of Dr. Tar’an’s work is that he is committed to reducing straw content while increasing seed production in future varieties. He has had to delve back in time and use flax’s wild ancestor, Linum bienne. By using historial genetics, Tar’an can benefit by breeding their old, shorter varieties with new modern varieties that have bushier plant structure, therefore, higher yielding qualities and improved harvestability.

Flax can have a strong future on the Prairies and Manitoba Crop Alliance is supporting that possibility for our farmers. It is a crop that requires patience and consideration, which we believe Manitoba farmers are great at and can help us solidify the flax industry on the Prairies. Discussions with farmers that have been growing flax successfully for several years tell us that it is one of the top most profitable crops on their farms because they are willing to put an extra effort in to the crop. In this case, it doesn’t mean inputs, directly. These farmers are treating flax like the special crop that it is; slowing down and using precision and sustainable practices to support the germination of a tiny seed into a beautiful and profitable crop.

Please contact the MCA’s Agronomy Extension Specialist for Special Crops if you are considering growing flax or currently work with flax and are interested in more agronomic information.