Report of bacterial leaf streak on barley seedlings, central Alberta, May 25 and 26, 2023

Symptoms of bacterial leaf streak observed on barley seedlings, central Alberta, May 25 and 26, 2023

Symptoms of bacterial leaf streak were observed in a barley field in Lacombe County based on field visits on May 25 and 26, 2023.  The symptoms were characterized by water-soaked lesions along the midrib of early leaves, mainly the first true leaf and were at a trace level in the field.  Water soaked streaks are the initial symptoms followed by yellowing and necrosis of the affected areas.  During wet conditions droplets of bacterial ooze may be observed on leaf lesions, while dried ooze tends to have a "glazed doughnut" appearance. Bacterial streaming was observed from samples with further molecular-based identification of causal agents being done.

Seedling symptoms of bacterial leaf streak have already been reported from a barley field in southern Alberta in the county of Warner around May 23rd.  See the following for more information regarding the southern Alberta observations, management suggestions and examples of bacterial leaf streak versus fungal leaf spots in barley.   https://prairiecropdisease.blogspot.com/2023/05/report-of-bacterial-leaf-streak-on.html.

Photos of bacterial leaf streak symptoms on barley seedlings, Lacombe County, May 26, 2023, courtesy of AAFC Lacombe.  Note soil particles and other debris can be seen on some of the leaves and this is not associated with typical symptoms of bacterial leaf streak.

The PCDMN wishes to acknowledge Carol Holt and Taryn Kanngiesser of Crop Doc Services Ltd. for their careful observations of bacterial leaf streak at the seedling stage from this central Alberta field on May 25 and 26, 2023. 

Report of bacterial leaf streak on barley seedlings, southern Alberta, May 23, 2023

Symptoms of bacterial leaf streak observed in barley, southern Alberta, May 23, 2023

With crops emerging, it’s time to scout for pests and diseases that can reduce yield. Don’t forget to add bacterial leaf streak (caused by Xanthomonas translucens) to your cereal diseases scouting list. Symptoms of this disease – such as water-soaking lesions along the midrib of early leaves – have already been reported in barley in southern Alberta in the county of Warner around May 23rd.  Water soaked streaks are the initial symptoms followed by yellowing and necrosis of the affected areas.  During wet conditions droplets of bacterial ooze may be observed on leaf lesions, while dried ooze tends to have a "glazed doughnut" appearance. 

While there are no in-season management options for control of bacterial leaf streak, monitoring and recording the appearance, progress and impact of the disease will help you learn by experience what might be expected in subsequent years.

Management recommendations include:

• Use seed with little or no detectable bacterial leaf streak risk
• Rotate crops to provide at least a two-year break between cereal crops
• If possible, allow the canopy to dry thoroughly between irrigation events

Photos showing bacterial leaf streak symptoms from a barley field in southern Alberta, May 23, 2023, courtesy of Joshua Leffers, independent agronomist.  

Photos of cereal seedling water soaking and more mature lesions with bacterial oozing due to bacterial leaf streak, courtesy of Drs. Connie Fleitas and Randy Kutcher, University of Saskatchewan, Saskatoon, SK.

Prairie Crop Disease Monitoring Network, Quick Disease Reporter Tool Update map for bacterial leaf streak as of May 25, 2023.  Map courtesy of Matthew McBurney, GIS Data Modeller, AAFC Winnipeg.

Bacterial leaf streak symptoms on barley seedling leaves are quite distinct from those caused by the fungal leaf spot complex that includes scald, net- and spot-form net blotch, and spot blotch.  Scald initially starts out as oval lesions that can have a water-soaked appearance.  However,  lesions then turn a grayish or turquoise colour, while mature scald lesions have a tan coloured interior with dark purple-brown borders and yellowing around the lesions.  Net and spot blotch symptoms start off as small brownish lesions that may be oval in shape.  As the infection progresses and the lesions mature, there can be yellowing around the brownish lesions.  Net-form net blotch lesions can have a netted appearance with lesions being long and narrow, while symptoms of spot-form net blotch or spot blotch will be more oval to oblong in shape.  Confirmation of scald and net-form net blotch is fairly straightforward as symptoms are quite diagnostic, while differentiating symptoms of spot-form net blotch from spot blotch will require laboratory analyses.

More information on typical cereal leaf disease symptoms can be found at the following Prairie Crop Disease Monitoring Network (PCDMN) links:

Net-form net blotch in barley

Spot-form net blotch in barley

Scald in barley

Spot blotch in barley

Bacterial leaf streak (for wheat, but symptoms and management are similar for barley)

Typical photos of leaf spots in barley

Net-form net blotch from seedling leaves, AAFC Lacombe 2022

Early net-form net blotch lesions, AAFC Lacombe, 2019

More developed net-form net blotch lesions, AAFC Lacombe 2019

Mature net-form net blotch lesions, AAFC Lacombe 2019

Mature spot-form net blotch lesions, AAFC Lacombe 2019

Early spot-form net blotch lesions, AAFC Lacombe 2016

Mature spot-form net blotch lesions, AAFC Lacombe 2019

Early and more advanced spot blotch lesions, AAFC Lacombe 2011

Mature spot blotch lesions, AAFC Lacombe 2011

Mature spot blotch lesions, AAFC Lacombe 2011

Mature spot blotch lesions, AAFC Brandon 2019

Early scald lesion, Adelaide/Barossa Valley area, South Australia, 2008

More advanced scald lesions, Adelaide/Barossa Valley area, South Australia, 2008

Mature scald lesions, Adelaide/Barossa Valley area, South Australia, 2008

Mature scald lesions, AAFC Lacombe 2019

The PCDMN wishes to acknowledge Michael Harding, Alberta Agriculture and Irrigation and Joshua Leffers, independent agronomist for sharing the initial report of bacterial leaf streak at the seedling stage from southern Alberta, May 23, 2023.  Photos showing various symptoms of bacterial leaf streak from Drs. Connie Fleitas and Randy Kutcher, University of Saskatchewan are also sincerely acknowledged.

2023 Cereal Rust Risk Report (May 17-23, 2023)

The latest Prairie wind trajectory cereal rust risk report is available for download now at the following link: May 17-23, 2023 report.  

As of the week of May 17-23, 2023 the overall Prairie cereal rust risk assessment and need for in-crop scouting is as follows:

Pacific Northwest – Even though there were a number of reverse wind trajectories that passed over the PNW region and into the Prairies, given limited stripe rust development in the PNW, generally dry Prairie conditions, and relatively early stages of Prairie crop development, as of May 23, 2023 the risk of stripe rust appearance from the PNW is low and scouting for this disease in the Prairie region is generally not urgent.

Texas-Oklahoma corridor – Given limited leaf, stem, stripe and crown rust development in this corridor, no recent wind trajectories from this area, generally dry Prairie conditions and early stages of Prairie crop development, as of May 23, 2023 the risk of stem, leaf, stripe, and crown rust appearance from the Texas-Oklahoma corridor is limited and scouting for these diseases in the Prairie region is not urgent.

Kansas-Nebraska corridor – Given limited leaf, stem, stripe and crown rust development in this corridor, a limited number of recent wind trajectories from this area, generally dry Prairie conditions, and early stages of Prairie crop development, as of May 23, 2023 the risk of stem, leaf, stripe, and crown rust appearance from the Kansas-Nebraska corridor is limited and scouting for these diseases in the Prairies is not urgent.

2023 Cereal Rust Risk Report (May 10-16, 2023)

The latest Prairie wind trajectory cereal rust risk report is available for download now at the following link: May 10-16, 2023 report.  

As of the week of May 10-16, 2023 the overall Prairie cereal rust risk assessment and need for in-crop scouting is as follows:

Pacific Northwest – Even though there were several reverse wind trajectories that passed over the PNW region and into the prairies, given limited stripe rust development in the PNW, generally dry Prairie conditions, and early stages of Prairie crop development, as of May 16, 2023 the risk of stripe rust appearance from the PNW is limited and scouting for this disease in the Prairie region is generally not urgent.

Texas-Oklahoma corridor – Given limited leaf, stem, and stripe rust development in this corridor, a limited number of recent wind trajectories from this area, generally dry Prairie conditions and early stages of Prairie crop development, as of May 16, 2023 the risk of stem, leaf, stripe, and crown rust appearance from the Texas-Oklahoma corridor is limited and scouting for these diseases in the Prairie region is not urgent.  

Kansas-Nebraska corridor – Given limited leaf, stem and stripe rust development in this corridor, a limited number of recent wind trajectories from this area, generally dry Prairie conditions, and early stages of Prairie crop development, as of May 16, 2023 the risk of stem, leaf, stripe, and crown rust appearance from the Kansas-Nebraska corridor is limited and scouting for these diseases in the Prairies is not urgent.  

Prairie Crop Disease Monitoring Network Quick Disease Reporter Tool (PCDMN QDRT), Updated Mini Tutorial Spring 2023

To help facilitate awareness of developing plant disease issues on a regional- and prairie-wide basis, the Prairie Crop Disease Monitoring Network (PCDMN) and the three Prairie provincial pathologists have worked with colleagues from the Agriculture and Agri-Food Canada (AAFC) Geomatics Group since summer 2021.  The result of this collaboration is the development and deployment of the Prairie Crop Disease Monitoring Network Quick Disease Reporter Tool (PCDMN QDRT).  

This PCDMN Blog post provides an updated mini tutorial as several changes have been made to the tool since it was first introduced in 2021.  Most of these reflect respecting privacy concerns for those individuals submitting reports.  With the update the actual PCDMN QDRT reporting process relies on identifying the municipality where the field is located.  No GPS info for an individual field is shared.

The revised mini tutorial can be accessed at this link: PCDMN QDRT Mini Tutorial May 2023

The PCDMN QDRT can be used to make quick general reports of diseases in common crops over the Prairie region as part of the Prairie Crop Disease Monitoring Network.  These reports will be used to prepare PCDMN QDRT disease update maps.  Initially our target is to provide weekly map updates.  The map will be shared via the PCDMN Blog and PCDMN Twitter feed as well as via provincial government or producer group crop/disease updates during the summer.  PCDMN QDRT reports will aid in identifying regions where disease outbreaks are starting to occur.  This information provides a timely heads-up for producers and crop consultants indicating where further in-crop scouting and risk assessment are needed, especially when a fungicide application is being considered.  Please note the success of the PCDMN QDRT is dependent on farmer, consultant/agronomist, researcher and producer group/provincial extension staff participation.  The greater the number of reports the better able we are to inform individuals and organizations regarding emerging disease issues so they can take appropriate timely actions.

Mini Prairie cereal rust update – May 11, 2023

Around May 16, 2023 we will be issuing our first full cereal rust risk update.  However, for this week we will provide an indication of rust development in the USA and whether this poses a risk for the Prairie region.

 

1)      Rust development in the Pacific Northwest

a)       Dr. X Chen from USDA ARS/Washington State University, issued their first rust update for 2023 on May 1, 2023.  https://www.wawg.org/stripe-rust-report-may-1-no-rust-found-in-commercial-fields/.

b)      Although Dr. Chen reported increased stripe rust on susceptible wheat and barley in their winter nurseries at Mount Vernon in the Northwestern Corner of WA; however, no stripe rust was observed in winter wheat fields several counties in WA and Oregon. 

i)        In southwest BC, Dr. G. Singh, University of British Columbia (UBC) Vancouver noted natural stripe rust development in a UBC winter wheat disease nursery (https://twitter.com/gurcharn_brar/status/1652865201165815809).

c)       As of May 12, 2023, there is a currently a low risk associated with the PNW being a significant source of stripe rust inoculum for dispersal into the Prairie region of Canada.  For the PNW, Dr. Chen indicates that given no to low levels of stripe rust, early season fungicide application is not recommended for winter wheat.  However, he indicates that if stripe rust is observed then fungicide application should be considered.

 

2)      Rust Development in the Texas to Oklahoma corridor

a)       Dr. O. Fajolu with the Cereal Disease Laboratory, USDA St. Paul, MN issued the first cereal rust bulletin for 2023 on April 27, 2023.  Reports were based on updates from Dr. A. Ibrahim, Texas A&M University, College station, TX, ([CEREAL-RUST-SURVEY] Rust Evaluation Nursery, Castroville, TX - 15 March 2023).  See: https://www.ars.usda.gov/ARSUserFiles/50620500/CRBs/2023%20CRB%20April%2027.pdf.

b)      Stem, leaf and stripe rust of winter wheat and stem and crown rust of oat have been reported in Texas, while stripe rust was also reported in Oklahoma.

c)       Increased levels of stem rust were reported in a stem rust nursery at Castroville, TX that were naturally inoculated.  Although low levels of leaf rust were observed in the same nursery in early March, by mid April high levels were observed.  In addition, increased levels of leaf rust were observed in sentinel trials and/or nurseries in several counties in TX. 

d)      Although stripe rust was observed in early March in a Castroville nursery, later observations in mid March indicated limited further development, while stripe rust was not active based on observations in mid April. 

e)      Oat stem rust at a Castroville nursery was limited in late March, but had increased significantly by mid April.  Oat crown rust has also been observed at increased levels in nurseries at Castroville and Weslaco, while it was also observed at College Station, but at lower levels. 

f)        There have been early May reports of trace levels of leaf and stripe rust on winter wheat at Stillwater, OK, while there were earlier reports of stripe rust at Chickasha, OK in late April.

(1)    Dr. M. Aoun, Oklahoma State University, Stillwater, OK, Wheat Disease Update – 10 May 2023, https://spotlight.okstate.edu/wheat-pathology/2023/05/11/wheat-disease-update-10-may-2023/.

(2)    OSU Wheat Pathology, https://twitter.com/OSUwheatdisease/status/1649611333124456449, https://twitter.com/OSUwheatdisease/status/1653531437503754240, https://twitter.com/OSUwheatdisease/status/1656454090870915072, https://twitter.com/OSUwheatdisease/status/1656451012838969344.

g)       As of May 12, 2023, there is a low risk associated with the Texas/Oklahoma region being a significant source of stem, stripe, leaf and crown rust inoculum for dispersal into the Prairie region of Canada.  This is mainly related to limited rust development in commercial fields, although rust has been observed in several disease nurseries.

 

3)      Rust Development in the Kansas to Nebraska corridor

a)       Stripe rust was reported at low levels in Edwards County in Kansas, while the risk of stripe and leaf rust is considered low as of May 9, 2023 (KSU Wheat Pathology, https://twitter.com/search?q=leaf%20rust&src=typed_query&f=live).

b)      Leaf and stripe rust has also been observed in inoculated nurseries by Dr. M. Guttieri, USDA ARS/Kansas State University, Manhattan, KS, April 21 and May 6, 2023 (https://twitter.com/Wheat_MaryG/status/1649414564595789832, https://twitter.com/Wheat_MaryG/status/1654859732715294721).  

c)       As of May 12, 2023, there is a low- risk associated with the Kansas/Nebraska region being a significant source of stem, stripe, leaf and crown rust inoculum for dispersal into the Prairie region of Canada.  This is mainly related to limited rust development in commercial fields, although leaf and stripe rust have been observed in several disease nurseries.

 

Stay tuned for further Prairie rust risk updates over the coming weeks!

The Prairie Crop Disease Monitoring Network (PCDMN) is ramping up activities for the 2023 growing season

The Prairie Crop Disease Monitoring Network (PCDMN) is ramping up activities for the 2023 growing season.  Moreover, we are entering Phase 2 of the PCDMN with funding from various producer organizations and Saskatchewan and Alberta funding bodies.  

Stay tuned for updates to the Blog and more extensive coverage of a wider range of Prairie crops and diseases!  

The weekly PCDMN Prairie Cereal Rust Risk forecasts will start soon.  In the meantime we have updated the rust risk overview document which you can access at this link: 2023 PCDMN Cereal Rust Risk overview.  New for the rust risk forecasts is the addition of crown rust of oat, while we will also monitor the stem rust situation in the Pacific Northwest (PNW) as there have been increasing concerns regarding stem rust, especially on barley, in this region (Upadhaya et al. 2022). 

References:

Upadhaya, A., Upadhaya, S.G.C., and Brueggeman, R.  2022.  The wheat stem rust (Puccinia graminis f. sp. tritici) population from Washington contains the most virulent isolates reported on barley.  Plant Disease 106: 223-230.  https://doi.org/10.1094/PDIS-06-21-1195-RE.