Search

Giant ragweed

Encyclopedia Article

Giant ragweed             Ambrosia trifida L.

Family:  Asteraceae (Composite family)
Life cycle:   Annual   
Native status: Native to North America      
Habitat:  Crop fields, flood plains, field edges

Category: 

Giant ragweed emergence patterns

Encyclopedia Article

Giant ragweed is usually the first summer annual weed to emerge that poses significant problems in Iowa corn and soybeans.  Giant ragweed usually initiates emergence in early April in Iowa, typically 2 to 4 weeks earlier than giant foxtail.  In ISU studies, giant ragweed also has had a very rapid emergence pattern, typically reaching 50% emergence in less than a week of initial emergence.  In contrast, in Ohio and Illinois giant ragweed typically did not reach 50% emergence for 6 to 7 weeks after the first seedling emerged.  Although there have been few studies on this t

Category: 
Crops: