View from the Field – East – Manitoba Pulse & Soybean Growers

Pulse and Soybean Crop Update for Eastern Manitoba for August 5, 2026

Field Peas:

Most crop stages range from flat pod (R3) with continued to flowering to full pod (R4). Some of the earliest seeded crops are experiencing canopy and pod color change – beginning maturity (R5). Growth has been rapid given the weather conditions experienced over the last two weeks and the crop is expected to move to harvest maturity very quickly. Growers are preparing for harvest.
Aphanomyces and Mycosphaerella blight continue to be observed in fields from mild to severe levels across eastern Manitoba. In particular dense and tall canopied field peas, sclerotinia stem rot (white mould) has been found. Plant wiliting and lodged canopies have resulted. Root rots have been particularly prevalent where excess moisture conditions were the most severe and persistent. Overall, most growers have been pleasantly surprised at how well field pea crops has fared given the weather conditions this growing season. That being said, in areas of Eastern Manitoba where there continues to be persistent saturated soils, standing water and field flooding due to continued rainfall, damage to field pea crops was extensive with some crops terminated.
Some final insecticide applications to control pea aphid took place over the last two weeks where deemed necessary.

Soybeans:

In the majority of fields, Crop stages range from beginning pod (R3) to full pod (R4) . Fields that were previously quite uneven or delayed in their development are now uniform in growth stage. Overall plant stature and biomass is continuing to increase dramatically as is expected during reproductive stages.
Some very late application timings of herbicides (i.e. beyond R1 or R2) occurred over the last two weeks. Some growers had delayed herbicide applications as long as they dared to prevent making deep ruts or becoming stuck in fields with excess moisture. Weed control has now pretty much wrapped up as crops move well out of labelled growth stages. For producers with continuing persistent weed issues, pre-harvest control measures are now being planned to mitigate harvest challenges.
While persistent saturated soils and standing water in the soybean crop was the story from May to mid-July, over this last two weeks soybeans were observed showing droughty symptoms such as leaf flipping and late afternoon wilting. While not severe thus far, the appearance of these symptoms confirmed for many that another shot of rain in mid-August will be important in many production areas for the crop to maximize yield potential. It is amazing what two weeks for heat will do to change crop conditions. A moisture top up to finishing filling those top pods would be a benefit in most of eastern Manitoba.

Field Observations up to August 5, 2026

Seed Production Field of Forage Peas – Photo Credit: Terry Buss

Field Peas look better than expected but we need to dig into that canopy

Overall in Eastern Manitoba, field peas crop look better than expected given the weather challenges we have had.
However, digging into the canopy to see what is happening at the lower stem and root level is important to get the true picture and set yield expectations accordingly.
The field pictured above is displaying good yield potential but a closer examination revealed sclerotinia starting to develop in the lower canopy and progressing at a rapid pace – see image below.

Sclerotinia (White Mould) developing on lower stems in field pea canopy – Photo Credit: Terry Buss

This field was sprayed twice with fungicide but canopy conditions were excellent for the development of sclerotinia (sustained canopy wetness into the afternoon and cooler temperatures than ambient at the canopy base due to heavy plant cover). Since the variety grown has standability issues (not uncommon for forage peas), it was intercropped with canola. This has helped with standability but not canopy aeration and also provided a ready host for sclerotinia. Good control of Mycosphaerella blight was achieved.
Not all stems were infected but those plants that were infected were starting to wilt. Nothing can be done at this point in terms of control measure interventions. Hopefully the crop fills and matures quickly to mitigate further sclerotinia development. Sclerotinia in field peas is not usually the disease we are most concerned about but the special circumstances with this field demonstrates that it can still be an issue in some circumstances.

Aphanomyces infected pea root in a jar – Photo Credit: Terry Buss

A disease being observed in eastern Manitoba field pea fields and considered the most important threat to field pea production in western Canada is Aphanomyces root rot.
The above image is a jarred sample of a field pea root infected with Aphanomyces root rot. It was on display at the University of Manitoba Plant Science Research Tour held on July 23, 2026 at the Ian N. Morrison Research Farm in Carman.
The jarred sample was part of a presentation about the Field Pea Crop Rotation Study being conducted by Kristen MacMillan (MPSG Agronomist-in-Residence) and her research team. One issue this study explores is whether more diverse and longer crop rotations that include field peas will result in decreased yield losses from Aphanomyces root rot.
Aphanomyces became the problem that it is in Western Canadian field pea production because of increased cropping frequency of field peas. Tight rotations led to very quick disease development. Once the problem is established in a field, it cannot be eliminated. But, less frequent field pea crops in rotation can lead to a decline in Aphanomyces infection levels.
Currently, industry recommendations regarding how frequently field pea can be included in crop rotations to avoid increasing the incidence of Aphanomyces root rot range from 1 in 4 to 1 in 9 years. More research is needed to put a finer point on this recommendation. And no research on this question has been conducted in Manitoba. The results of Kristen’s research will provide critical information needed to plan suitable crop rotations to minimize this disease problem.
For more information see: Aphanomyces Root Rot in Peas – Manitoba Pulse & Soybean Growers

Busy Season for Field Tour Presentations this year

Terry Buss being casual during a presentation at the Sevita Soybean Summit – Photo Credit: Susan Buss

Wendy McDonald and I would like to thank the folks at Sevita International for giving us the opportunity to present agronomic information at their Sevita Soybean Summit held on July 29, 2026 in the Bagot Area.
Topics discussed included soybean seeding depth, group 4 herbicide symptoms, rapid growth syndrome, soybean inoculation and evaluating nodulation as well as rescue strategies in case of inoculation failure.
Wendy and I have been speaking at many events and tours this summer and are gratified that folks have wanted us out to share our experiences. We look forward to many more opportunities to talk soybeans with growers before summer comes to an end.
It’s also obvious that I really need to get back on my exercise routine. Walking fields is not enough exercise to keep me slim!!