Refining and making accessible to growers a validated dynamic action threshold for cereal aphid control in cereal crops

Project Code PRR15-040

Project Lead

Erl Svendsen      Agriculture and Agri-Food Canada

Objective

To refine, validate and transfer a previously developed dynamic action threshold (DAT) model as a tool to help growers make spray decisions for aphid management in cereal crops

Aphids are a serious periodic threat to wheat, oat and barley in the Canadian prairies but growers have only two chemical control options: dimethoate and malathion, both organophosphate insecticides. Consequently, in 2011, a Pest Management Centre (PMC)-led stakeholder working group identified cereal aphids as a priority pest issue to be addressed by the PMC’s reduced risk management strategy for Foliar Insect Pests of Prairie Field Crops. Further, the working group identified the need to establish a dynamic action threshold (DAT) for cereal aphid management that considered the presence of beneficial natural enemies within the crop. As a result, a 2-year project PRR12-040 was initiated in spring 2012 to develop a Prairie cereal aphid DAT tool similar to a soybean aphid management tool developed for Ontario growers.

Based on 2 years of field data, the project team developed a cereal aphid DAT model prototype. A small scale validation trial in the second study year revealed that the prototype over-estimated the number of aphids killed by individual natural enemies. Therefore, the DAT prototype needs to be refined and re-validated before delivering it as a spray decision support tool to growers.

This new 3-year project aims to update and refine the existing cereal aphid DAT tool prototype. This will be accomplished by developing a better understanding of population dynamics and interactions between aphids and their natural enemies through conducting extensive monitoring in commercial cereal crops across Saskatchewan and Manitoba. The updated DAT tool prototype will be re-validated for prediction accuracy against field observations. The ultimate goal is to make the DAT tool available as an interactive smart phone app for growers to use in making spray decisions. A secondary goal is to familiarize growers with the important role(s) that natural enemies play in controlling aphid populations and with management practices that can conserve and enhance natural enemy populations.

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