Friday, 14 June 2019

Predicted grasshopper development (June 13, 2019; Wk 10)

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). 

This week, the grasshopper hatch is well underway across the prairies with most locations having 30% (12% last week) hatch and some areas are predicted to have hatch rates of 75%. Approximately 21% of the population is in the first instar (Fig. 1), 7% (2,5% last week) is predicted to be in the second instar (Fig. 2), and 1% in the third instar.  Grasshopper developmental rates are greatest across southern and central regions of SK. Over the past 30 days this region has experienced the warmest and driest conditions for the prairies. Recent, warm temperatures in southern MB has advanced grasshopper development. 

A survey of roadsides south of Saskatoon this week indicated that melanopline species were primarily first and second second instars.  
Figure 1.  Predicted percent of grasshopper (Melanoplus sanguinipes) population at first instar stage acrossthe Canadian prairies (as of June 11, 2019). 

Figure 2. Predicted percent of grasshopper (Melanoplus sanguinipes) population at second instar stage acrossthe Canadian prairies (as of June 11, 2019). 

Biological and monitoring information related to grasshoppers in field crops is posted by Manitoba AgricultureSaskatchewan AgricultureAlberta 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.