**Kudzu Caterpillars** are the larvae of the **Black Swallowtail Moth** (*Papilio polyxenes*) and several other moth species that feed on the foliage of the invasive **Kudzu vine** (*Pueraria montana*). The most common species are actually polyphagous, meaning they feed on many plants, but Kudzu is a common host plant. While their feeding is minor on the Kudzu vine itself, the caterpillar is occasionally viewed as a minor nuisance pest when feeding on desirable host plants in the carrot family (Apiaceae), such as parsley, dill, or fennel, in a garden setting.
Taxonomy and Classification
Kudzu Caterpillars (referring to the Black Swallowtail) belong to the order Lepidoptera (moths and butterflies), family Papilionidae (swallowtails). They undergo complete metamorphosis. The larval stage is a key food source for birds, and the adult moth is an important pollinator. The caterpillar is native and beneficial, not a pest in the same sense as the Kudzu Bug.
Physical Description
The mature Black Swallowtail larva is 1 to 2 inches long.
- **Appearance (Key ID):** Bright green with transverse black bands and yellow or orange spots, making them highly visible on foliage.
- **Defense:** If disturbed, they evert a bright orange, fleshy, Y-shaped gland (**osmeterium**) from behind the head, which releases a foul, pungent odor to deter predators.
- **Adult:** A large, striking black butterfly with yellow/blue markings.
- **Conflict:** They cause minor defoliation of cultivated plants in the carrot family.
Distribution and Habitat
Found throughout North America wherever host plants (wild carrots, Queen Anne’s Lace, parsley, dill, Kudzu) are present. Their habitat is open fields, gardens, roadsides, and Kudzu-infested areas. They are active during the day.
Behavior and Conflict
The conflict is minor, limited garden loss.
- **Garden Feeding:** They are occasionally viewed as pests when they consume the leaves of cultivated garden herbs (parsley, fennel, etc.), but the damage is usually minor, and gardeners often tolerate them to allow them to mature into butterflies.
- **Kudzu Consumption:** They feed on Kudzu, but their impact is too minor to be considered a viable control agent for the rapidly growing invasive vine.
Management and Prevention
Management is generally limited to tolerance and physical removal.
- **Toleration (Key):** Most gardeners tolerate or encourage them due to the beauty of the adult butterfly.
- **Physical Removal:** If populations are high on high-value herbs, caterpillars can be manually picked off and relocated to wild host plants (like Queen Anne’s Lace).
- **Chemical Control:** Pesticides are rarely warranted and should be avoided to protect pollinators and other beneficial insects.
Conservation and Research
Kudzu Caterpillars (Black Swallowtails) are managed as a highly desirable native pollinator species. Research focuses on their role in the ecosystem and understanding the chemical communication mechanisms of their defensive osmeterium.