Tuesday, 25 June 2019

Predicted grasshopper development (June 27, 2019; Wk 12)

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).

Across the prairies the grasshopper hatch is well underway with most locations having approximately 27% of the population in the egg stage. Based on model runs, approximately 33% (30% last week) of the population is in the first instar, 26% (14.5% last week) is predicted to be in the second instar, and 11% (4.3% last week) in the third instar and just over 1% are predicted to be in the fourth instar.   The following map indicates that grasshopper populations across the southern prairie are mostly in the second instar.
Figure 1. Predicted development stages of grasshopper (Melanoplus sanguinipes) populations across
the Canadian prairies (as of June 24, 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 "Field Crop and Forage Pests and their Natural Enemies in Western Canada: Identification and management field guide" which is available as a free downloadable document in either an English-enhanced or French-enhanced version.