disease Archives - Manitoba Crop Alliance

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.

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.