Dynamic action threshold tool for aphid management in cereal crops on the Canadian prairies

Aphids reproduce through parthenogenesis and can rapidly increase their population which can lead to economic thresholds being quickly exceeded with the possibility of yield losses.  Cereal aphids and their predators and parasitoids were collected and identified from cereal fields (wheat and barley) across Saskatchewan and Manitoba (2012).  The majority of aphids collected were English grain aphids (EGA), Sitobion avenae Haliday (Hemiptera: Aphididae). An array of natural enemies (Anthocoriidae, Aphidiidae, Aphelinidae, Coccinellidae, Crysopidae, Nabidae) were also collected and their numbers correlated with the growth of the aphid population.  A computer model that incorporates the life history of predators and aphids was constructed in DYMEX™ to predict population growth of EGAs based on forecasted weather and the number of natural enemies in a field.  The model produces a dynamic action threshold (DAT) based on producer inputs and will recommend to spray if the economic threshold will be exceeded or not to spray if existing predators will control population growth.