The fifth weekly Prairie wind trajectory cereal rust risk report for 2024 is available for download now at the following link: June 4-10, 2024, report.
As of the week of June 4-10, 2024, the overall Prairie cereal rust risk assessment and need for in-crop scouting is as follows:
Pacific Northwest –
There were moderate numbers of reverse wind trajectories that passed over the
PNW region and into the Prairies, while the most recent reports available
indicate that stripe rust development is limited in commercial fields although
there are concerns that it could restart in previously sprayed commercial crops. Prairie winter wheat crops are progressing past
the stem elongation stages and into flag leaf emergence, booting and in some
regions heading, while much of the spring wheat crop has now been seeded and is
at the seedling to tillering stage.
Rainfall amounts were limited in the central to southern Alberta and
southwest and south central Saskatchewan.
Overall, as of June 12, 2024, the risk of stripe rust appearance from
the PNW is relatively low and scouting for this disease in the Prairie region as
a result of PNW rust inoculum is generally not urgent.
Texas-Oklahoma corridor –
There were only two reverse wind trajectories that passed over the TX/OK region
and into the Prairies from June 4-10, 2024, while stripe and leaf rust have
been reported. However, Texas and Kansas
winter wheat crops are either mature or will be shortly with harvesting close
to 50% complete. As a consequence winter
wheat crops in these regions no longer represent a significant source of rust
inoculum for the Prairie region. Prairie
winter wheat crops are progressing past the stem elongation stages and into
flag leaf emergence, booting and in some regions heading, while much of the
spring wheat crop has now been seeded and is at the seedling to tillering stage.
Overall, as of June 12, 2024, the risk of stem, leaf, stripe, and crown rust
appearance from the Texas-Oklahoma corridor is relatively low and scouting for
these diseases in the Prairie region based on inoculum from TX/OK is not urgent.
Kansas-Nebraska corridor –
There were only eight reverse wind trajectories that passed over the KS/NE region
and into the Prairies from June 4-10, 2024, while stripe and leaf rust (Kansas)
development have been reported in commercial winter wheat fields in this region,
with numerous reports of low levels in Nebraska, although elevated levels have
been reported in unsprayed fields, especially where the variety planted was
susceptible. Note, Kansas winter wheat
crops are progressing towards maturity with a small percentage being
harvested. As a consequence over the
next 1-2 weeks Kansas winter wheat will no longer represent a significant
source of rust inoculum. Prairie winter
wheat crops are progressing past the stem elongation stages and into flag leaf
emergence, booting and in some regions heading, while much of the spring wheat
crop has now been seeded and is at the seedling to tillering stage. Rainfall amounts in southern Saskatchewan and
the central regions of Manitoba were reduced, although some regions in central
to northern Saskatchewan and west central, northwestern and the southeastern
corner of Manitoba had higher rainfall amounts.
The rainfall in regions with higher amounts could facilitate deposition
of rust spores into cereal crops and subsequent disease development. Overall, as of June 12, 2024, the risk of stem, leaf, stripe, and crown rust
appearance from Kansas-Nebraska corridor inoculum is low-moderate and scouting
for these diseases in the Prairies is generally not urgent.
The early and widespread appearance of stripe rust in the PNW, TX/OK and KS/NE regions is still concerning, while the recent stripe rust observations from North Dakota, South Dakota, Minnesota and Wisconsin bring the stripe rust issue very close to the Prairies, especially the central to eastern regions. Over the next 1-3 weeks if favourable weather conditions (especially more rainfall) occur in these source US regions, further rust development could occur. This would result in more rust spores being available to be blown into the Prairie region, as well as more northerly rust development into the Dakotas and Minnesota/Wisconsin. Currently, Prairie winter wheat fields are most at risk, but fortunately most current winter wheat varieties have intermediate to high levels of resistance, although AC Radiant, CDC Buteo, AAC Elevate, Broadview, and CDC Falcon are rated as susceptible (https://www.seed.ab.ca/variety-data/cereals/; https://saskseed.ca/wp-content/uploads/2020/12/2024-Varieties-of-Grain-Crops.pdf; https://www.seedmb.ca/pdf-editions-and-separate-section-pdfs/). In terms of spring wheat (various classes) and durum the following varieties are either an S or MS: 5700PR, AAC Cameron, AAC Iceberg, AAC Tisdale, AAC Tomkins, AAC Warman, AAC Whitefox, AC Foremost , Cardale, CDC Abound, CDC Adamant, CDC Flare, CDC Pilar, Faller, Prosper, SY Natron, SY Rorke, SY Torach, and Unity. If you are growing a stripe rust susceptible variety, it will be important to keep an eye on your crops for stripe rust especially and follow further PCDMN cereal risk updates (https://prairiecropdisease.blogspot.com/).
