Development and validation of a dynamic action threshold for cereal leaf beetle in the Canadian prairies

Project Code PRR16-020

Project Lead

Haley Catton and Hector Carcamo   Agriculture and Agri-Food Canada

Objective

To develop an action threshold for cereal leaf beetle which will enable growers to take into account the role of natural enemies when making insect pest management decisions in the field

Since first found in southern Alberta in 2005, the cereal leaf beetle (Oulema melanopus L.) has expanded its range and increased in prevalence causing damage in cereal crops across the Canadian prairies. Economic thresholds for this pest are lacking in Canada, and spraying insecticides to prevent anticipated yield loss regardless of knowledge of pest presence or risk for sufficient damage may be uneconomic. Moreover, chemical sprays may be unnecessary when biological control organisms such as the parasitoid Tetrastichus julis and other natural enemies of the cereal leaf beetle are established and sufficiently abundant in the area to keep the pest in check. These insecticide treatments may actually be counterproductive, as they can be harmful to these beneficial insect species.

This 3-year project starting in spring 2016 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 the crop. The studies will be conducted in a key wheat growing region of southern Alberta which experiences high pest pressure in order to establish a threshold suitable for the Canadian prairies. The project also aims to educate growers about using science-based thresholds to make informed spray decisions as part of an integrated cereal leaf beetle management program. It is anticipated that adoption of such a decision support tool will harness the ecosystem services of beneficial organisms and reduce unnecessary pesticide use in cereal cropping systems.

 

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