Reduced-risk management strategy for foliar insect pests of Prairie field crops

For inquiries regarding this strategy, please contact:
Pest Management Centre, Agriculture and Agri-Food Canada
pmc.cla.info@agr.gc.ca

August 2016

Preface

Pesticide risk reduction strategies are developed under the Pesticide Risk Reduction Program (PRRP), a joint initiative of Agriculture and Agri-Food Canada (AAFC) and the Pest Management Regulatory Agency (PMRA) of Health Canada. The Program’s objective is to reduce risks to the environment and to human health from pesticide use in agriculture. To achieve this, the Program works with grower groups, provincial experts and researchers to identify gaps in pest management and opportunities for pesticide risk reduction, and to develop and implement strategies to address these.

A pesticide risk reduction strategy is a detailed plan that aims to address grower needs for reduced-risk management tools and practices for specific pest issues. The strategies are developed through extensive consultations with stakeholders. The strategy document presented here summarizes the framework and activities supported by the Programme. It is intended to provide an update on the progress in developing and implementing the strategy and new tools and practices made available through this process.

For more information, please visit the Pest Management Centre.

Acknowledgement

The Pesticide Risk Reduction Program acknowledges the contribution of participating organizations and stakeholders, including the current and former members of the Foliar Insect Pests of Prairie Field Crops Working Group:

  • John Gavloski - Manitoba Agriculture, Food and Rural Development;
  • Jim Broatch and Scott Meers - Alberta Agriculture, Food and Forestry; Jim Bessel, Troy Prosofsky, and Greg Sekulic - Canola Council of Canada;
  • Dan Johnson - University of Lethbridge; Bill Ross - Manitoba Canola Growers; Patricia Flaten and Errin Tollefson - SaskCanola;
  • Scott Hartley, Sean Miller and Danielle Stephens - Saskatchewan Ministry of Agriculture;
  • Kenton Possberg - Western Canadian Wheat Growers;
  • Owen Olfert, Hector Carcamo, Bob Elliott, Jennifer Otani, Julie Soroka, Chrystel Olivier, Erl Svendsen, Tyler Wist and Haley Catton - Agriculture and Agri-Food Canada.

Executive Summary

Many insect species causing above-ground feeding damage to plants can be serious pests that affect yield and quality of economically important field crops across Canada. Following systematic assessments, priority pests with the greatest potential for pesticide risk reduction were identified by stakeholders. Control of these pests relies mainly on the application of older, broad-spectrum insecticides, some of which are undergoing regulatory review by Health Canada's Pest Management Regulatory Agency (PMRA). Thus, safer solutions are needed to control these pests.

This report summarizes the support from the Pesticide Risk Reduction Program towards developing reduced-risk alternatives to manage foliar insect pests of field crops, with a focus on the prairie region. Some of the outcomes resulting from this work may be applicable to other regions of Canada where similar crops are grown.

A strategy to address these pests has been developed in collaboration with provincial crop specialists, research scientists, and industry stakeholders. The most pressing crop/pest issues were selected, solutions were discussed and prioritized, and an action plan was put into place. Selection of solutions was driven by the goal to achieve viable pest management while reducing risks associated with the use of insecticides, including pest resistance to these products.

To date, the Program has funded 13 projects addressing cereals, canola and alfalfa to implement this strategy. The pest species targeted for the above crops are aphids, cereal leaf beetle, Lygus bugs, cabbage seedpod weevil, and alfalfa weevil. Tools generated for growers so far include:

  • A monitoring network to estimate risk for seven insect pests in three prairie provinces
  • A new guide Field Crop and Forage Pests and their Natural Enemies in Western Canada
  • A validated alfalfa weevil prediction model, adapted for the Canadian prairie region
  • The relocation of a parasitoid wasp for biological control of the cereal leaf beetle
  • The prototype of a dynamic action threshold for the control of aphids in cereal crops
  • An updated economic threshold for Lygus bug in canola.

Grasshoppers, an important pest of field crops, were not included here as these have been addressed previously through the Reduced-Risk Strategy for Grasshopper Management.

More details about the projects and solutions resulting from this strategy are provided in the below tables. Adoption of the new tools will enable growers to enhance their integrated pest management practices and reinforce judicious use of chemical insecticides.

Pest management and pesticide risk reduction issues

Foliar pests include numerous insect species which affect field crops in Canada. This strategy work focuses on the three Prairie Provinces because of the predominantly large acreage of field crops grown in this region. Out of a total of over 21 million hectares of field crops grown in Canada annually, 93% of cereals and 98% of canola are grown in the Prairie Provinces.

Significant amounts of pesticides are sprayed over large crop areas to protect crop quality and yields from foliar pests, especially during outbreaks. Most insecticides available are older chemistries that belong to two main groups, organophosphates and pyrethroids. Several of the products are being re-evaluated in light of new science and some of the registered uses may be eventually phased out. Moreover, repetitive use of a few insecticides with similar modes of action is a risk factor in the development of insect resistance to these products.

Therefore, a need was identified to diversify the tool box with alternative control options suitable for integrated pest management systems. This strategy is working to develop reduced risk solutions and decision support tools to facilitate sustainable management of priority pests.

Strategy development

Some gaps were previously identified for this group of pests through preliminary stakeholder consultations in 2003 and 2005. In response, the Program supported several projects addressing these gaps, while emphasizing the need for broader stakeholder engagement and a more concerted approach across the prairie region.

Working group consultations

In fall 2011, a working group was established to help the Program develop a plan of action to address these pest issues. The group brought together subject matter experts and stakeholders, including grower organizations, university researchers, and scientists, as well as provincial extension and pest management specialists.

Priority issues and gaps

Through multiple rounds of consultations over five years, the working group has progressively identified several gaps in pest management and associated reduced risk solutions for high priority foliar pests. These pests had been treated regularly with older insecticides and the need for alternative control options in the toolbox was critical. Top crop/pest needs identified to-date:

Cereals

  • 1a. Cereal aphids

    There was a need to develop and validate a dynamic action threshold tool that takes into account natural enemies of aphids present in cereal crops. A similar model previously developed for soybean aphid management in Ontario gave rise to the idea of adopting such approach in cereals.

  • 1b. Cereal leaf beetle

    Economic and dynamic (which takes into account the role of natural enemies associated with the pest present in a crop) action thresholds were needed for the Prairie regions. In addition, a highly effective biocontrol agent of cereal leaf beetle that had previously been introduced needed to be relocated into new areas where the pest was becoming endemic.

  • 1c. Wheat midge

    Growers needed a simple way to apply the new science and technologies available in their decision making process for the management for this pest.

Canola

  • 2a. Lygus bugs

    The 20-year-old economic thresholds needed to be updated for current canola cultivars, economics and climatic conditions.

  • 2b. Cabbage seedpod weevil

    Control options with reduced risk to bees were needed for use during blooming of canola to protect foraging bees and other beneficial insects.

  • 2c. Diamondback moth

    An economic threshold needed to be developed and validated for the prairie region.

Forages

  • 3a. Alfalfa weevil

    Improved monitoring and prediction techniques for informed management decisions and knowledge on the status of key biocontrol agents were needed for this pest in the prairies.

Other (overarching areas)

  • 4a. Given that the only comprehensive pest management tool available to field crop growers was the Insect Pests of the Prairies published in 1989, a new field guide with up-to-date information was needed to help growers with proper identification of key pests and beneficial insects of field crops, as well as with integrated pest management approaches.
  • 4b. Establish a coordinated prairie-wide insect pest monitoring network.

Action Plan

An action plan targeting the following goals was put in place to address the various issues listed above in a deliberate, sequential approach:

  • Develop biological pest control options as alternatives to insecticides;
  • Improve pest management decision making to minimize unnecessary insecticide sprays;
  • Develop IPM technologies and educate growers about the new knowledge and techniques developed through this strategy.

The below tables outline the goals of the strategy along with the solutions recommended by the working group members and the actions taken by the Program to implement them.

Progress to implement a reduced-risk strategy for foliar insect pest management in prairie field crops (August 2016)

Goal #1: Develop biological pest control options

Milestone

Recommended solutions

(Crop/pest code)*

StatusResults from projects undertaken by the Program**Completion Date
Evaluate the potential for cabbage seedpod weevil biocontrol in canola (2b) Completed PRR03-370 Assessing potential non-target risks of biological control agents used in IPM against cabbage seedpod weevil. Due to concerns with the breadth of host range revealed by host plant-weevil-parasitoid associations, no steps were taken to release any of the tested biocontrol agents. New non-target host test lists were developed for the Canadian Food Inspection Agency (CFIA). 2003-2007
Support regulatory submission for XenTari for diamondback moth control in canola Completed BPR12-030 Evaluation of XenTari for the management of diamondback moth in canola. Efficacy data generated was used by registrant (Valent Biosciences) to complete the registration package for XenTari WG Biological Insecticide (Bacillus thuringiensis ssp. aizawai) submitted to PMRA. XenTari was registered for use for diamondback moth control in canola in November 2014. 2012-2013
Relocate cereal leaf beetle parasitoid Tetrastichus julis into new areas of cereal crops (1b) Completed PRR13-020 Expanding distribution of existing parasitoid to new areas for bio-control of cereal leaf beetle in small grain cereals in the Canadian prairies. From 2013 to 2015, about 14,000 Tetrastichus julis wasps were relocated and released in various wheat fields of Alberta, Saskatchewan and Manitoba where the pest had become prevalent, but the parasitoid was not recorded or parasitism was at insufficient levels. Also, a landscape ecology study indicated that abundance of cereal leaf beetle decreased in cereal fields surrounded by landscapes that had a high proportion of non-cropped habitat. 2013-2016
Status legend:
  • Completed: Activity is complete
  • In-progrss: Activity addressing milestone is underway
  • Future: Areas recommended for future work or promotion

* Crop/pest code corresponds to the number of issues listed under ‘Priority issues and gaps’

** Hyperlinked codes: Project synopses and results summaries available on Pest Management Centre website

Goal #2: Improve pest management decision making

Milestone

Recommended solutions

(Crop/pest code)*

StatusResults from projects undertaken by the Program**Completion Date
Establish a coordinated prairie-wide insect pest monitoring network to inform growers on pest risks (4b) Completed PRR07-060 Development of reduced-risk strategies through coordinated monitoring, forecasting and risk warning systems for insect pests of field crops in Canada. A monitoring network was established for seven pest species across three prairie provinces and data were translated into interpretive risk maps indicting near real time distribution and density of each target pest. Collection of data and delivery of this service to growers continues through the Prairie Pest Monitoring Network. 2007-2010
Update economic threshold for Lygus bug in canola (2a) Completed PRR12-030 Refine and validate economic threshold for Lygus bugs in canola production in Alberta. Project provided preliminary recommendations against spraying irrigated canola fields for Lygus control at pod stage. Work to further refine these recommendations continues under other sources of funding. 2012-2014
Develop a dynamic action threshold for cereal aphids that takes into account natural enemies of aphids present in the crop (1a) Completed PRR12-040 Develop and validate a dynamic action threshold (DAT) tool for aphid management in cereal crops in the Prairies. A new DAT prototype was developed to predict growth of cereal aphid populations accounting for changing numbers of aphids and their natural enemies. The model needs further refinements and field validation before recommending to growers as a tool for making informed spray decisions. 2012-2014
In-progress PRR15-040 Refining and making accessible to growers a validated dynamic action threshold (DAT) for cereal aphid control in cereal crops. Project aims to develop an online application for growers to access an operational and field validated DAT developed earlier in project PRR12-040. The DAT is expected to recommend a pesticide spray when the populations of predators and parasitoids of cereal aphids are insufficient to prevent the pest from reaching the economic threshold. 2015-2018
Make available prediction tool for alfalfa weevil in prairie regions (3a) Completed PRR13-010 Improve decision-making for monitoring and management of alfalfa weevil in alfalfa crops on the prairies. The project validated degree-day models which best determined the stage of alfalfa weevil development. The prediction tool has been made available to growers since 2015 through the Prairie Pest Monitoring Network. The project also revealed that the parasitoid wasp Bathyplectes curculionis, a natural enemy of alfalfa weevil, is well established across Saskatchewan and is present in Manitoba. 2013-2015
Develop field guide to identify harmful and beneficial insects of field crops in the Prairie (4a) Completed PRR13-040 Production of a field guide on pest and beneficial insects and mites of field crops in western Canada. Project developed an illustrated 150 page publication titled Field crop and forage pests and their natural enemies in Western Canada available in English and French. Both print and electronic (USB card and on-line) formats of the guide were widely distributed and promoted to stakeholders. 2013-2015
Develop economic thresholds for cereal leaf beetle (1b) In-progress PRR16-020 Development and validation of a dynamic action threshold for cereal leaf beetle in the Canadian prairie. This project aims to develop and field validate an action threshold that incorporates elements of the density and voracity of important natural enemies of the cereal leaf beetle present in wheat crops. The goal is for growers to use this tool to make informed spray decisions in the field. 2016-2019
Develop economic thresholds for diamondback moth in canola (2c) Future Not applicable Not applicable
Status legend:
  • Completed: Activity is complete
  • In-progrss: Activity addressing milestone is underway
  • Future: Areas recommended for future work or promotion

* Crop/pest code corresponds to the number of issues listed under ‘Priority issues and gaps’

** Hyperlinked codes: Project synopses and results summaries available on Pest Management Centre website

Goal #3: IPM technology development and transfer

Milestone

Recommended solutions

(Crop/pest code)*

StatusResults from projects undertaken by the Program**Completion Date
Promote IPM adoption and pesticide risk reduction strategies in cereals Completed PRR06-870 Accelerating the adoption of Integrated Pest Management and risk management strategies in wheat and other cereals. Project determined existing adoption levels of selected IPM systems in cereals and encouraged further uptake of best management practices through on-farm demonstrations and educational activities. 2006-2009
Develop integrated control approaches for cabbage seedpod weevil (2b) Future Not applicable Not applicable
Develop IPM educational tool for wheat midge (1c) Future Not applicable Not applicable
Status legend:
  • Completed: Activity is complete
  • In-progrss: Activity addressing milestone is underway
  • Future: Areas recommended for future work or promotion

* Crop/pest code corresponds to the number of issues listed under ‘Priority issues and gaps’

** Hyperlinked codes: Project synopses and results summaries available on Pest Management Centre website

Strategy outcomes

Major outcomes from the implementation of this strategy to date include:

  • Field crop growers now have easy access to new science and decision support tools to inform integrated management actions for some priority insect pests;
  • Field crop growers have access to scientifically based recommendations on the incorporation of biological control agents and natural enemies in integrated pest management systems for some priority insect pests;
  • Large cohorts of field crop growers, crop advisors, and pest management specialists have been informed about the use of new tools and approaches made available through this strategy work.

It is anticipated that by making these new tools and approaches available and educating growers in their use, more sustainable crop protection practices will be adopted, whereby growers reduce their reliance on chemical insecticides and practice better resistance management.

This report will be updated periodically as new projects are completed and new information becomes available.


Alternative Formats

Help with Alternative Formats

Reduced-Risk Strategy for Foliar Insect Pests of Prairie Field Crops (PDF version, 124 KB)

Date modified: