Predicted grasshopper development (May 17, 2018; Wk 02)

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 13, 2018, predicted mean egg development was 68% (62% last week) and model output indicates that embryological development was 5% greater than long term average. Greatest development was predicted to be across southern Alberta with potential for hatch occurring near Medicine Hat and Bow Island (Fig. 6).

Figure 1. Grasshopper (M. sanguinipes) embryological development (%) based on
model simulations for April 1-May 13, 2018.

Reminder - The Prairie Pest Monitoring Network's 2018 Grasshopper Forecast Map was released in March (Fig. 2).  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 2018 growing season.

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.