Pestipedia

Vine Weevils

**Vine Weevils** (*Otiorhynchus sulcatus*) are highly destructive pests, particularly to containerized ornamental plants, soft fruits (e.g., strawberries, raspberries), and grapes. They are flightless, black-snouted beetles. The conflict is **root destruction and defoliation**: the **larval stage (white grub)** feeds voraciously on the roots, often girdling the crown of the plant and causing sudden collapse, while the adult feeds on the leaves, leaving characteristic **scalloped, notched margins**.

Taxonomy and Classification

Vine Weevils belong to the Family Curculionidae (Snout Beetles). They undergo complete metamorphosis. Females often reproduce asexually (**parthenogenesis**), meaning all individuals are capable of laying eggs.

Physical Description

Adults are 8 mm to 10 mm long.

  • **Adult (Key ID):** Dull black, flightless, with a short, broad snout; body is covered in minute, light-colored hairs giving a dusty appearance.
  • **Larva (Key ID):** White, legless, C-shaped grub with a distinct brown head, found in the soil around roots.
  • **Damage ID (Key):** Scalloped leaf edges (adult feeding); sudden wilting or death of the entire plant (larval root feeding).
  • **Conflict:** Agricultural, Ornamental.

Distribution and Habitat

Found worldwide, particularly in temperate regions. Habitat is garden soil, nursery containers, greenhouses, and fields growing soft fruit and ornamentals.

Behavior and Conflict

The conflict is their dual damage and cryptic nature.

  • **Nocturnal Feeding:** Adults feed on foliage only at night and hide in soil or debris during the day, making them difficult to detect.
  • **Parthenogenesis:** Asexual reproduction allows populations to grow rapidly without the need for males.

Management and Prevention

Management is **Targeted Biological and Chemical Control**.

  • **Biological Control (Key):**
    • Application of **entomopathogenic nematodes** (*Heterorhabditis* spp.) to the soil when larval stages are active (late summer/early autumn).
  • **Chemical Control:**
    • Targeted application of insecticides to control adult populations before egg-laying begins.

    • Conservation and Research

    Research focuses on improving the efficacy and timing of nematode application and developing soil-drench systemic insecticides for commercial use.