Sunflower Survey 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

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 3rd 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.

Lambda-cyhalothrin update – March 2025

Lambda-cyhalothrin insecticide – a fast-acting stomach and contact insecticide that provides control of several foliar pest in various crops. It is a synthetic pyrethroid and group 3A insecticide.

In April 2021, the PMRA published and announced that lambda-cyhalothrin and all associated end-use products underwent a re-evaluation decision. As is well-known, the final decision at the time was to cease all sales of lambda-cyhalothrin products in Canada. Another re-evaluation in 2023 determined that the insecticide could only be used on crops not being used, in any form, for human or animal feed consumption.

Health Canada’s PMRA made the most recent update on February 3, 2025, which appears to be a generous re-evaluation of lambda-cyhalothrin to reinstate certain feed uses of the product. Several livestock feed uses have been re-instated, which are generally grain, meal and by products. Feed uses not re-instated are several silages, stover, forage, hay and straw products, plus some others. The full list can be found in the latest publication here.

Unfortunately for confection sunflower farmers, lambda-cyhalothrin has not been re-instated for the control of lygus bugs. Products for direct human consumption do not appear to have potential for reinstatement on the insecticide’s label. Oilseed sunflowers are not affected as readily by lygus bug damage because their impact to the oil content of the seed is not as detrimental as quality is to confection sunflowers.

Lygus nymph and adult.

Manitoba Crop Alliance has worked together with Manitoba Agriculture and FMC Canada in 2023 and 2024 to ensure confection farmers have Carbine (R) insecticide available for use on confection sunflowers to control lygus bug. This occurred via a 12-month Emergency Use Registration. The current EUR is valid until July 2025, so the three groups are working on another 12-month EUR and FMC Canada is making efforts toward a permanent registration of the product via the PMRA.

Carbine (R) Insecticide is a group 29 insecticide that is an “ideal partner in integrated pest management (IPM) – has minimal impact on beneficial insects and pollinators when applied according to the label,” and “has no known cross-resistance to other active ingredients,”  according to FMC Canada.

Additional Information: Lygus bugs are a major pest of sunflowers because they can cause kernel brown spot, which is a small brown to black spot on the blunt end of the seed. The industry standard allows for a maximum of 0.5% kernel brown spot in confection sunflowers marketed for human consumption. The economic threshold for lygus but in confection sunflowers is one bug per 9 sunflower heads. Each adult lygus bug is capable of damaging as many as 35 seeds per head.

Control of lygus bug is very limited and insecticides (lambda-cyhalothrin) are the most effective option in sunflowers. Cultural options are even more limited. When planning sunflower acres, it is recommended to avoid planting near adjacent canola fields since they are both favourable host crops to lygus bug. Canola does have limited insecticide options available for lygus bug, so in canola-lygus infestation and insecticide application scenarios, those neighbouring lygus bugs will attempt to move out and find another host crop, like sunflowers.

Some environmental and biological control factors from Manitoba Agriculture include:

  • Weather: Heavy rainfall may reduce levels of early-instar nymphs of lygus bugs. A study in alfalfa found heavy rainfall reduced first generation nymphs of Lygus lineolaris by 50%.
  • Biological Control: Nymphs of Lygus bugs may be killed by parasitic wasps in the genus Peristenus (Hymenoptera: Braconidae); with parasitism being common in weedy alfalfa stands or uncultivated weedy sites but very low in canola. Damsel bugs, assassin bugs, lacewing larvae, big-eyed bugs and crab spiders can prey on lygus bugs. Protecting these natural enemies by avoiding unnecessary insecticide applications may also help to reduce the impact of lygus bugs.
Top