Predicted grasshopper development (Jun 14, 2018; Wk 06)

Grasshopper Simulation Model Output – The grasshopper simulation model will be used to monitor grasshopper development across the prairies. Weekly temperature data collected across the prairies is incorporated into the simulation model which calculates estimates of grasshopper development stages based on biological parameters for Melanoplus sanguinipes (Migratory grasshopper).  

As of June 11, 2018, predicted hatch was 74% (long term average was 28%). The average development is almost at second instar (Fig. 1) with 30, 28, 12 and 2% in the  first, second, third and fourth instar stages, respectively.  

Figure 1.  Grasshopper development (average instar) on model simulations, for April 1 – June 11, 2018.

Model output for Saskatoon illustrates that populations are primarily in the first and second instars with third and fourth instar stages beginning to appear (Fig. 2). This agrees with last week’s survey conducted south of Saskatoon SK. 

Figure 2.  Predicted grasshopper phenology at Saskatoon SK.
Values are based on model simulations, for April 1 – June 11, 2018.

Biological and monitoring information related to grasshoppers in field crops is posted by Manitoba Agriculture, Saskatchewan Agriculture, Alberta Agriculture and Forestry, the BC Ministry of Agriculture and the Prairie Pest Monitoring Network.  Also refer to the grasshopper pages within the new "Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide" as an English-enhanced or French-enhanced version.