By Donna Fleury
The Prairie Crop Disease Monitoring Network continues to expand in 2022.
Monitoring and managing crop diseases and other pests is a critical part of cropping systems. A co-ordinated insect surveillance program for the Prairies began more than 20 years ago and today is recognized as the very successful Prairie Pest Monitoring Network (PPMN). Researchers and industry were interested in developing a similar network for a co-ordinated field crop disease monitoring program for the Prairies.
A Prairie-wide project was launched in 2018 to design and implement the Prairie Crop Disease Monitoring Network (PCDMN). The PCDMN’s main focus is to provide timely information about crop diseases on the Prairies and to highlight effective disease management approaches. Kelly Turkington, plant pathologist with Agriculture and Agri-Food Canada (AAFC) in Lacombe, Alta., was asked by colleagues to lead this major project, with support from several collaborators from AAFC, Alberta Agriculture, Forestry and Rural Economic Development, Saskatchewan Ministry of Agriculture and Manitoba Agriculture and Resource Development.
“In our early conversations, there was a desire to have a similar network as PPMN devoted to crop diseases to encourage more consistent survey protocols among scientists, researchers and extension staff, as well as provide more tools relevant to producers and crop consultants,” Turkington explains. “The PCDMN is modelled after the very successful PPMN, with the goal to provide background resources and training on plant disease identification and interpretation, as well as developing protocols that can be used by a range of individuals.
“In terms of the network, crop diseases can be a bit more complex and cover a wider range of issues that are usually unique to individual crops. We launched the PCDMN in 2018, followed by the creation of a PCDMN Twitter account (@pcdmn) in 2019 and a blog in 2020. We graciously acknowledge the support of the PPMN in allowing us to pattern the development of our network on their success. The PCDMN blog was developed with the key assistance of Jennifer Otani, AAFC Pest Management Scientist and co-chair of PPMN, who generously stepped up to facilitate the blog. There are several other collaborators working on contributing to the different components of the project, with a modest funding budget from various contributors of approximately $25,000 annually.”
One of the larger project priorities is related to cereal rust risk monitoring, which has four components that help with risk assessment and management of cereal rusts on the Prairies. This includes information on rust development in source areas in the USA, the frequency of wind trajectories that bring wind parcels and rust inoculum or uredospores from rust source areas into the Prairie region, and Prairie weather conditions and crop growth stages. Typically, in mid-May each year the monitoring begins with weekly wind trajectory and rust forecasts.
“With cereal rusts on the Prairies, the inoculum (or uredospores) for the three main rust diseases leaf, stripe and stem rust, originates in the USA. The rust pathogens are highly adapted to long-distance transport on the wind, with thick, pigmented spore walls that resist desiccation and UV radiation. The primary source of stripe rust is traditionally the Pacific Northwest (PNW) including Washington State, northwest Idaho and Oregon. Leaf and stem rust primarily originate in Texas and up through Oklahoma and into Kansas/Nebraska, although recently stripe rust is becoming more of an issue in these regions. The air parcels can travel into Western Canada in as little as one day and up to two to four days, depending on source location, wind trajectory, and at-risk Prairie locations.”
The first step to rust forecasting is to determine how cereal rust is developing in the USA and whether there is sufficient inoculum to be a concern for Western Canada. Generally, rusts overwinter in winter wheat crops in the southern states or the PNW region and begin circulating in the spring, travelling long distances on wind parcels from source locations. Turkington follows rust development in the USA through Twitter posts, updates from the USDA Cereal Rust Lab in Minnesota and reports from Washington State University produced by lead pathologist Dr. Xianming Chen. The levels of inoculum development help determine the potential rust risk for Western Canada. However, the PCDMN also recognizes the potential for stripe rust to overwinter in the Prairie region on winter wheat and thus monitors reports of fall rust occurrence and spring development.
“We also use wind trajectory models to outline wind occurrence and frequency,” Turkington explains. “In the late 1990s, AAFC scientists Owen Olfert and Julie Soroka began working with Serge Trudel at Environment and Climate Change Canada (ECCC) to develop potential trajectory models as an early warning system for migratory invasive species such as diamondback moth. We realized these wind trajectory models could provide a similar early-warning system and forecast for rust spores arriving from the USA. We selected 29 key locations across the Prairie region where both insect pests and crop disease issues are a concern. The model uses both forward and backward trajectories for following air parcels through time, and identifying potential wind events that may carry rust spores from source areas in the USA.”
Turkington works closely with Saskatoon AAFC scientists Ross Weiss and Meghan Vankosky, who generate regular reports on the occurrence and frequency of wind trajectory events that pass over the 29 stations from rust source location states. In addition, they also provide weekly Prairie weather summaries. A report showing no trajectory indicates the risk is low. If wind trajectory incidence moves from a few occurrences to very frequent movement, that means there is more potential to carry rust spores from USA regions where there is a rust epidemic. The next step is to look at the weather conditions in the Prairies. Although the spores can settle out from the air by themselves, even a small amount of rain can wash the spores down and into the crop, increasing the risk. The rust risk forecast for the Prairies is then modified based on crop stages and whether the crop is winter wheat, where the key risk period of developing rust is earlier in mid-May, or for spring cereals where the risk period is into June and later as tillering begins. The rust forecasts are published on a weekly basis and include maps, tables, and a brief risk summary.
Other components of the project are the development of better, consistent disease scouting and disease monitoring protocols and tools. The team recognized early that it would be important to have consistent surveillance protocols and tools across the Prairies. Some of the protocols are mostly used by scientists, researchers and extension specialists who tend to be able to devote more time to do a thorough job of surveying. Other more straightforward and less time-consuming protocols and assessments are more likely be utilized by farmers or crop consultants who often have multiple fields to assess and less time to spend surveying. Researchers developed disease survey protocols for some key cereal, canola and pulse diseases. For example, assessment protocols were developed for leaf spot diseases in cereals, blackleg and sclerotinia stem rot in canola and ascochyta/mycosphaerella in field peas. The team also worked together with the provincial pathologists to prioritize the information that should be included for other disease identification tools being developed such as the disease information cards.
“In 2020, we started working with our AAFC Geomatics group, including Matthew McBurney and Ryan Tondevold, as well as provincial pathologists Mike Harding, Alireza Akhavan and David Kaminski from Alberta, Saskatchewan and Manitoba respectively. Initially, [McBurney] helped to develop a GIS mapping tool to outline municipal-level occurrence of rust. This was a huge step for the project, replacing the large amounts of time I originally spent creating individual municipality and provincial forecast maps by hand from various sources of surveillance data. With his expertise, we then started looking at a detailed surveillance reporting tool we could use to collect disease information in the field, especially towards the end of the season,” Turkington says.
“Collectively we discussed what farmers and crop consultants might need earlier in the season and [Harding] suggested something that would be less detailed and focused on identifying emerging issues. We felt that something was needed to aid in identifying regions where increasing reports of disease occurrence would signal developing disease issues that require in-crop scouting and assessment of fungicide need. From that idea, [McBurney] developed the Quick Disease Reporter Tool or PCDMN QDRT app that enables users to gather disease data in the field on a phone or tablet and submit it onsite automatically to a secure database,” Turkington adds. “In areas where Internet isn’t adequate, users can create a draft report and send it later when they have better access. The app has a map utility that users can click on their location or add GPS co-ordinates, plus drop-down menus to select the crop and disease. Users are required to upload a photo, which helps with disease verification. There is also an option to enter an email and ask for follow-up from a disease specialist. Users should note that all information gathered is rolled up on a municipality basis and held in a secure database, no individual information is ever shared.” (A tutorial was developed for the tool and is posted on the PCDMN blog.)
“We have made significant progress on the project and are looking forward to having the blog and cereal rust forecasts, the QDRT app, disease scouting cards and other information available for the coming growing season,” Turkington says. “We have completed a large amount of the upfront program design and foundational work to develop the Prairie Crop Disease Monitoring Network and make the blog and tools available. For 2022, we will continue to add disease information, expand the suite of disease information cards, and continue with disease surveillance and potential forecasting. It is anticipated that I will go into the QDRT database once or twice a week during the summer to review the reports submitted and generate the disease occurrence maps for the blog, but with [McBurney] and [Tondevold]’s help, we hope to automate that process in 2022 and have the maps generated automatically. It will still be important for someone like myself to go in and review the photos being submitted for example to make sure the disease reported is reflective of the symptoms, or if the disease is unknown we can work with pathologists for identification. In addition, we can follow up with anyone who submits information on the QDRT app and asks to be contacted. This information may also assist provincial pathologists and other researchers with an up-to-date comprehensive overview of disease occurrence and developments and potentially new issues that may be identified.
“Ultimately these tools provide a great early warning and heads up for producers and crop consultants to signal when to get out and scout their fields if the rust risk forecasts are showing increasing risk in their area, or where increasing appearance of diseases is occurring on a municipality basis. Some crop diseases can complete their life cycle in seven-to-14 days, such as leaf spot diseases in various crops. Even with a small amount of inoculum, if the host variety is extremely susceptible and weather conditions are very conducive to the disease, then a small amount of inoculum can quickly build as a crop progresses from seedling to early tillering and stem elongation stage. Therefore, an early warning system is very important to inform producers and consultants when to get out and scout their fields and be prepared for in-crop management strategies such as spraying fungicides if needed. This will hopefully prevent the situation where a disease looks like it overtook a whole field overnight, but earlier scouting might have identified it and provided options for management before it was too late. The broad range of tools and information that we are making available through the PCDMN blog is valuable to anyone in the agriculture industry interested in crop diseases and management across the Prairies.”
During the 2022 growing season, the fall of 2022 and winter 2023, Turkington and others plan to provide presentations and training at various crop field days and events across the Prairies. Disease identification, assessment protocols and other management tools will be the priority. The project ends in March 2023 and decisions about the long-term plan for maintaining the Prairie Crop Disease Monitoring Network are under discussion. For more information on the PCDMN, its funders and to keep up to date on crop diseases for the coming growing season, visit prairiecropdisease.blogspot.com.
The PCDMN project has had many collaborators and partners during its development. Funders include the Integrated Crop Agronomy Cluster, AAFC and the Canadian Agricultural Partnership, Western Grains Research Foundation, and several crop industry associations across the Prairies.