**Striped Cucumber Beetles** (*Acalymma vittatum*) are small, bright yellow beetles that are highly destructive pests of cucurbit crops, including **cucumbers, squash, pumpkins, and melons**. The conflict is threefold: they cause direct damage by **chewing holes in leaves and stems** (especially seedlings); they feed on the flowers and fruit; and, most critically, they are the primary vector for the devastating bacterial disease **Bacterial Wilt** (*Erwinia tracheiphila*), leading to total crop failure.
Taxonomy and Classification
Striped Cucumber Beetles belong to the order Coleoptera (Beetles). They undergo complete metamorphosis. The larvae feed on the roots of the host plant, but the adult beetles are responsible for almost all the plant and disease damage. They overwinter as adults and are one of the first pests to emerge in the spring.
Physical Description
Adult Beetles are small, 1/4 inch long.
- **Appearance (Key ID):** Bright **yellow** body with **three conspicuous longitudinal black stripes** running down the wing covers. They are highly active and jump or fly quickly when disturbed.
- **Damage Sign (Key ID):**
- **Holes:** Small holes chewed in cotyledons and true leaves of seedlings (early damage).
- **Wilt:** Sudden, dramatic wilting of one or more runners or the entire plant, often in the absence of drought (sign of bacterial wilt).
- **Scars:** Scarring and pitting on developing fruit.
- **Conflict:** Plant destruction and severe disease vectoring.
Distribution and Habitat
Striped Cucumber Beetles are found throughout North America, east of the Rocky Mountains. Their habitat is the foliage and roots of cucurbit crops in gardens and fields.
Behavior and Conflict
The conflict is dominated by the rapid disease spread.
- **Bacterial Wilt:** The beetle acquires the bacteria by feeding on an infected plant and transmits it through its mouthparts and feces when it feeds on healthy tissue. This disease is systemic and lethal to the plant.
- **Seedling Vulnerability:** They are most damaging to young plants, often killing the plant before it can produce true leaves.
- **Pollen Feeding:** Adults feed on pollen and may congregate in flowers, interfering with pollination.
Management and Prevention
Control is integrated pest management (IPM), with a heavy focus on exclusion and early protection.
- **Row Covers:** Cover plants with fine-mesh floating row covers immediately after planting or seeding. **Crucially, remove the covers when flowering begins** to allow pollinators to access the flowers.
- **Sanitation:** Remove and destroy any infected (wilted) plants immediately to reduce the source of both the disease and the beetles.
- **Targeted Treatment:** Apply a registered pyrethrin or carbaryl insecticide to young plants if beetle numbers are high and exclusion is not possible. Timing is critical to kill the beetles before they transmit the bacteria.
Conservation and Research
Striped Cucumber Beetles are managed as severe agricultural pests. Research focuses on breeding cucurbit varieties resistant to bacterial wilt, improving trap cropping strategies, and understanding the overwintering biology of the adult beetle.