Cabbage White Butterfly
Pieris rapae
How did it get here?
The cabbage white traveled from Europe to Quebec, Canada in 1860 on cargo ships. It is now one of the most widespread and common butterflies in North America.
How to spot
Look for cabbage white butterflies and their larvae spring
through summer, beginning in March. The butterfly is small
and white, about 1¾ inches to 2¼ inches from wingtip
to wingtip. The fore
wing has a black tip, with one spot in male and two
spots in females. The undersides of the wings are yellow-green
or gray-green. 
The butterfly has a bouncing, fluttery, or floating flight and often feeds on the nectar of garden flowers. The caterpillar (larval stage of the butterfly) is about 1 inch long. It is fuzzy and green with a broken yellow line on each side and a yellow line on its back. It responds sluggishly if disturbed. Look for eggs and caterpillars on cabbage or broccoli plants.
Habitat characteristics
Pieris rapae is found almost everywhere: cities, suburbs, gardens, roadsides, marshes, and open, weedy areas.
Life Cycle
Adults
emerge as early as March and lay eggs on the undersides
of leaves. The yellow eggs are rocket-shaped and ridged.
They hatch in three to seven days. The caterpillar feeds
on its host plant for two weeks before attaching 
to
a leaf and pupating
in a ¾-inch pale-green chrysalis.
The butterfly emerges in one to two weeks. Five generations
of butterflies are produced each growing season.
Look-alikes and how to distinguish
• Checkered white (Pontia protodice)—checkered
front wing; underside of hind wing plain white or patterned.
• Mustard white (Pieris napi)—completely
white with no spots; veins outlined in gray or green visible
on underside of hind wing.
• West Virginia white (Pieris virginiensis)—rounded
fore wing; hind-wing veins on underside outlined in brown
or gray-brown.
Why is this insect a problem?
The
cabbage white caterpillar eats vegetable crops, including
cabbage, broccoli, brussel sprouts, collards, kale, kohlrabi,
mustard, and the leafy tops of turnips, radishes, and
rutabagas.
May outcompete
native species of white butterflies that feed on wild
mustards.
Management approaches
- Hand-pick caterpillars from plants in small gardens.
- Place row covers on crops to prevent adults from laying eggs on plants.
- Control infestations either chemically or biologically. For more information on these methods, see http://ohioline.osu.edu/hyg-fact/2000/2201.html or www.vegedge.umn.edu/vegpost/colecrop/cabbworm.htm
Other resources
Web Sites
University
of Georgia Entomology
Fact sheet
University
of Illinois Extension
Fact sheet
Literature
Opler, Paul. 1998. A field guide to eastern butterflies. Peterson Field Guide Series. Boston: Houghton Mifflin.
Pyle, Robert Michael. 1995. Field guide to North
American butterflies. National Audubon Society Field
Guide Series. New York: Alfred A. Knopf.
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