In alternate years, the National Sunflower Association performs a sunflower survey in six states (ND, SD, MN, CO, KS and NE). The survey looks at several agronomic pests and pressures and the potential yield impacts in the given year. In 2023, Manitoba Crop Alliance (MCA) participated in the survey with the help of Ahmed Abdelmagid, research scientist for oilseed crops pathology at Agriculture and Agri-Food Canada’s (AAFC) Morden Research and Development Centre. Nine sunflower fields were surveyed in Manitoba, reflecting the approximately 85,000 total sunflower acres in 2023.

This project serves two purposes:

1. Identifying factors that affected yield in the given year and which may be of increasing importance in the future, and
2. Identifying potential research priorities.

Factors that were looked at specifically during the survey were the following:

• Yield components – plant population, head diameter, seed size, % good seed, % centre seed set, bird damage
• Agronomic information – crop type, row width, tillage practices
• Weed Assessment
• Diseases
• Insect & bird damage

Fields were visited in mid- to late-September, once R9 was reached and each was surveyed at two different sites within the field. Of the nine Manitoba locations, six were oilseed production fields and the remaining three were confections, and all locations were distributed throughout southern Manitoba from Eastman to Westman areas.

The initial process in each sampling location was to do a plant count followed by another count including only “harvestable” plants (this would not include very small heads, heads with no seed, lodged plants). These harvestable plants were used in yield estimation against all the factors that lay ahead. Head diameter was measured in inches on five plants per location and centre seed set was measured (diameter of seed not set in the centre of each head). Next, seed samples were taken from three heads and stored in a paper bag to send for testing, but not before determining percentage good seed (% filled seed) and seed size.

A general assessment of the field was made at each sample location for yield limiting factors (birds, disease, insects, weeds, drought, uneven plant growth, hail, herbicide damage, lodging and plant spacing within the row) and the top two limiting factors were ranked. The most common limiting factor across the nine surveyed fields was disease (five fields) and the remaining four fields had greatest limiting factor being birds, drought, lodging or weed pressure. It was rare to find a second limiting factor in these fields, which had a positive impact on yield due to less pressure on the crop.

Bird damage was estimated in the percentage of seeds lost. Five fields had bird damage at the time of surveying, ranging from 0.5 – 4.5 per cent seed loss. Surveying is typically done around the same time blackbirds tend to begin feeding on sunflowers and one of these surveyed fields had a significant increase in bird damage by harvest.

Insect presence measurements accounted for sunflower midge, sunflower seed maggot, sunflower bud moth and long-horned beetle damage (not found in Manitoba). 25 heads at each field site were examined for the above insect damage, aside from long-horned beetle, which required stalk splitting to identify the larvae presence.