Friday, 2 June 2017

Weekly Update (Jun 1, 2017; Wk 05) - Predicted Grasshopper Development

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 29, 2017, predicted mean embryological development was 77% (70% last week); the greatest development was predicted to be across southern regions in all three provinces, particularly southern Alberta (Fig. 1). Hatch was predicted for a few, isolated locations with approximately 7% hatch (Fig. 1).
Figure 1. Predicted embryological development of Migratory grasshopper  (Melanoplus
) eggs across the Canadian prairies as of May 29, 2017.

For comparison, the map below (Fig. 2) indicates that the predicted M. sanguinipes hatch is actually slower than normal. This week, 93% of the population should be in the egg stage and 6.5% in the first instar. Predicted warm conditions for May 31 and June 1 should result in completion of the egg stage.  Though it is still early in the growing season, grasshopper hatch can vary across the prairies. 

Figure 2.   Predicted embryological development of Migratory grasshopper  (Melanoplus sanguinipes) eggs
across the Canadian prairies as of May 29, 2017, using Long Term Normal data

- Review the predicted M. sanguinipes phenologies generated for Week 4 for Regina SK, Lethbridge AB and Grande Prairie AB.
- The Prairie Pest Monitoring Network's 2017 Grasshopper Forecast Map can be viewed here.  

Biological and monitoring information related to grasshoppers in field crops is posted by Manitoba Agriculture, Food and Rural DevelopmentSaskatchewan 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.