**Trumpet Vine Weevils** (*Anthonomus grandis* or similar Weevils that infest *Campsis radicans*) are small beetles whose larvae bore into various parts of the trumpet vine. The conflict is aesthetic damage and reduced flowering: the larvae bore into and feed on **flower buds, new shoots, or seed pods**, causing the buds to **drop prematurely**, the shoots to **wilt**, or the seed pods to be destroyed. This directly reduces the flowering and aesthetic appeal of the ornamental vine.
Taxonomy and Classification
Trumpet Vine Weevils belong to the order Coleoptera (Beetles), family Curculionidae (Weevils). They undergo complete metamorphosis. The larval stage is protected inside the plant tissue where it feeds.
Physical Description
Adult Weevils are small, 1/8 to 1/4 inch long.
- **Adult (Key ID):** Small, dark, robust weevil with the characteristic long, thin snout (rostrum).
- **Larva (Key ID):** Small, white, C-shaped, legless grub found inside the damaged buds or pods.
- **Damage Sign (Key ID):**
- **Wilted Buds:** Flower buds shrivel and drop before opening, often with tiny pinholes visible near the base.
- **Bored Seeds:** Seeds inside the mature seed pod have been hollowed out by the feeding larva.
- **Wilted Tips:** Tips of new shoots suddenly wilt and die back (“flagging”).
- **Conflict:** Aesthetic loss and reduced flowering/seed production.
Distribution and Habitat
Varies based on the specific species, often found across eastern North America. Their habitat is the foliage and new growth of the trumpet vine.
Behavior and Conflict
The conflict is dominated by the hidden nature of the larva.
- **Protected Feeding:** Once the egg is laid and the larva is inside the bud or shoot, topical insecticides are ineffective.
- **Flowering Loss:** The primary host (trumpet vine) is valued for its striking flowers, and loss of buds is highly noticeable.
Management and Prevention
Control is integrated pest management (IPM), relying on pruning and monitoring.
- **Remove Infested Buds:** Immediately remove and destroy all fallen, wilted, or damaged flower buds and seed pods to eliminate the developing larvae.
- Use a registered insecticide applied as a foliar spray at the time of bud formation to kill the adult weevils before they lay eggs. This must be timed precisely and requires careful monitoring.
- Maintain healthy vines to help them quickly grow past the minor damage.
Conservation and Research
Trumpet Vine Weevils are managed as ornamental pests. Research focuses on their specific host-plant preference and the use of systemic insecticides for protected control.