Predicted grasshopper development (May 31, 2018; Wk 04)

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).  

Above normal temperatures have advanced grasshopper development (Figs. 1 and 2). As of May 28, 2018, predicted hatch was 31% (up from 6% last week).

Figure 1. Grasshopper embryological development (%) based on model simulations (April 1-May 28, 2018). 

Figure 2.  Grasshopper hatch (%) based on model simulations (April 1-May 28, 2018).

Reminder - The Prairie Pest Monitoring Network's 2018 Grasshopper Forecast Map was released in March (Fig. 3).  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 3.  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.