Apple weevil

Otiorhynchus cribricollis

Otiorhynchus cribricollis, commonly known as the Vine Weevil, is a notorious pest that poses a threat to a wide range of plants, including ornamentals, fruit trees, and various crops. Belonging to the family Curculionidae, this weevil is particularly known for its nocturnal feeding habits and the damage it inflicts on plants.

Key Characteristics:

  1. Adult Beetles: The adult Vine Weevils are approximately 1/4 to 1/2 inch (6 to 12 mm) long and have a distinct dull black color. They are characterized by their broad, oval-shaped bodies, short snouts, and elbowed antennae.

  2. Feeding Behavior: Adult Vine Weevils feed on the leaves of various plants, creating characteristic notches along the edges. However, the most destructive stage is the larvae.

  3. Larvae: The larvae of Otiorhynchus cribricollis are creamy-white, legless grubs with a distinctive C-shaped appearance. They feed on the roots of plants, causing significant damage and often leading to wilting and decline.

Life Cycle:

The life cycle of the Vine Weevil includes four stages: egg, larva, pupa, and adult.

  1. Egg: The female weevil lays eggs in the soil, typically near host plants.

  2. Larva: Upon hatching, the larvae feed on plant roots, causing the most damage during this stage.

  3. Pupa: The larvae pupate in the soil before emerging as adult weevils.

  4. Adult: The nocturnal adult weevils emerge from the soil, and they feed on plant leaves during the night.

Management:

  1. Biological Control: Introduce natural predators such as predatory nematodes or entomopathogenic nematodes that target the larvae in the soil.

  2. Chemical Control: Insecticides can be used to manage adult weevils, but they may not be as effective against the concealed larvae in the soil.

  3. Soil Drenches: Applying insecticide as a soil drench can be effective against the larvae. This is typically done in late summer or early fall.

  4. Preventive Measures: Implement preventive measures such as inspecting new plants for signs of infestation before introducing them to the garden, and use barrier methods like sticky traps.

  5. Cultural Practices: Improve overall plant health through proper watering, fertilization, and soil management, as healthy plants are better able to withstand weevil damage.