Predicted grasshopper development (May 30, 2019; Wk 08)

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 28, 2019, predicted grasshopper egg development was 72% (66% last week) and is similar to long term average values (75%) (Fig. 1).  Across the prairies, the grasshopper hatch is just beginning with most locations having less than 5% hatch. 

Figure 1. Predicted grasshopper (Melanoplus sanguinipes) embryological development acrossthe Canadian prairies as of May 28, 2019. 

Figure 2. Predicted percent of grasshopper (Melanoplus sanguinipes) population at first instar stage acrossthe Canadian prairies (as of May 28, 2019). 

Model runs for Grande Prairie (Fig. 3), Lethbridge (Fig. 4) and Saskatoon (Fig. 5) were projected to June 15, 2019. Results for Lethbridge and Saskatoon indicated that second instars will begin to appear next week. Hatch in near Grande Prairie is  predicted to be approximately one week later.  Development is predicted to be more advanced in northern areas of the Peace River region. 

Figure 3. Predicted status of Melanoplus sanguinipes populations near Grande Prairie AB as of  May 28, 2019.  

Figure 4. Predicted status of Melanoplus sanguinipes populations near Lethbridge AB as of  May 28, 2019.  

Figure 5. Predicted status of Melanoplus sanguinipes populations near Saskatoon SK as of  May 28, 2019.  

This week we surveyed roadsides south of Saskatoon. Though counts were low, melanoplines were primarily first with a few second instars. Slant faced grasshoppers were most abundant, particularly Aeropedellus clavatus.

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.