Predicted grasshopper development

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 May 4, 2020, grasshopper embryonic development is marginally ahead of long term normals.  Development has been greatest across Saskatchewan and Alberta (Table 1, Fig. 1).


Table 1. Predicted percent embryonic development of M. sanguinipes populations at selected sites across the Canadian prairies as of May 4, 2020.

Figure 1. Grasshopper embryological development (%) based on model simulations using
current environmental conditions (as of May 4, 2020).

Reminder - The Prairie Pest Monitoring Network's 2020 Grasshopper Forecast Map was released last week (Fig. 2) in the 2019-2020 Risk and Forecast Maps.  Spring temperatures, soil moisture conditions, and precipitation all have an impact on survival of overwintered grasshopper eggs. Growers in areas highlighted orange or red in the map below should be vigilant this spring.

Figure 2.  Grasshopper forecast map (M. sanguinipes) for 2020 growing season (released January 2020).

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 "Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide" (Philip et al. 2018) as an English-enhanced or French-enhanced version.