Thursday, 8 June 2017

Weekly Update (Jun 8, 2017; Wk 06) - 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 June 5, 2017, model output suggests that most of the population is still at the egg stage. However, recent warm conditions have advanced grasshopper development. Predicted hatch was 23% (17% first instar and 6% second instar) across the prairies (up from 7% last week). Development was predicted to be most advanced across southern regions in all three provinces, particularly southeastern Alberta and a region extending south from Regina to the USA border. 

Though it is still early in the growing season, grasshopper hatch can vary across the prairies. Model output indicates that development near Vauxhall is one week ahead of Saskatoon and three weeks faster than Grande Prairie. This suggests that peak hatch at Grande Prairie may not occur until late June.

The following image showing various stages of the clearwinged grasshopper is provided below - note that adults have wings extending the length of the abdomen whereas nymphs lack wings but develop wing buds that will eventually mature to wings.  

- 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.