Crop & Pest Report
What Are These White Butterflies Flying Around? (8/25/11)
I’ve received many calls and emails about all of the white butterflies flying around ditches, canola, and other areas and whether they are an insect pest. These butterflies belong to the insect family Pieridae and to the group called Sulphurs and Whites, which are usually white or yellow in color.
Most of their caterpillars are green, usually with one or more pale lateral stripes. Their body surface is covered with minute hairs, which gives them a velvety appearance. Larvae of resident species overwinter as chrysalids.
At
least 14 species of this group occur in North Dakota. Common examples include
the checkered white, cabbage butterfly or imported cabbageworm and alfalfa
butterfly. The cabbage butterfly or imported cabbageworm is one of the most
common and is attracted to plants in the mustard family (cabbage, broccoli,
cauliflower, canola) and can be an occasional garden pest. However, it is
typically not an insect pest of canola. Female cabbage butterflies have two
black spots on forewings and males only one spot. The alfalfa butterfly is
rarely an insect pest of alfalfa in North Dakota. So, enjoy the beautiful
butterflies!
Janet J. Knodel, Extension Entomologist
NDSU Crop & Pest Report - May 24, 2012
