Small White

The cabbage white butterfly (Pieris rapae), also known as the cabbage butterfly and the imported cabbageworm, is so named because the larval stage feeds on members of the cabbage family (Cruciferae). This species is found around the world in temperate climates. It was introduced to North America in the 1860's and has since spread throughout the continent. The cabbage white butterfly is known to pollinate several species in the United States. The cabbage white butterfly has a black body with white wings. The upper wings have a black band at the tip and a black spot in the center of each upper wing. Males have one spot on each wing and females have two. The underneath of the wings are yellowish-green. These butterflies have a wingspan of 30 to 50 mm. Caterpillars are green or bluish-green with a light yellow stripe.

These butterflies are one of the first to be seen in the spring and one of the last to be seen in the fall. These butterflies can fly from February to mid-November; they have a shorter season in their northern range and a longer season in the south. Females produce between 300 and 400 eggs; each is laid singly on the underside of host plants. Caterpillars hatch and feed on plants from the cabbage family (Brassicaceae). They then molt five times before turning into a chrysalis. Chrysalids hibernate and hatch into adult butterflies. Adults live about three weeks. Cabbage white butterflies have between two and eight generations per year.

Recent research has shown that it is actually four times more efficient at pollinating wild radish (Raphanus raphanistrum) than honey bees (Apis mellifera) because honey bees are foraging for both pollen and nectar and most likely groom away pollen from their bodies. In addition to wild radish, cabbage white butterflies are pollinators of red clover (Trifolium pratense), common dandelion (Taraxacum officinale), black-eyed susan (Rudbeckia hirta), buttonbush (Cephalanthus spp.), bird's-foot violet (Viola pedata), and wild strawberry (Rosaceae). In addition to being pollinators, this species can be considered a pest because the larvae feed on the foliage of crop plants like broccoli, Brussels sprouts, cabbage, cauliflower, collard, horseradish, kale, and kohlrabi. Larvae of this species have the ability to reduce mature plants to stems and large veins by eating foliage. Larvae have also been known to burrow into the heads of broccoli and cabbage; they are difficult to dislodge and produce large amounts of fecal material.