Rape stem weevil

Ceutorhynchus napi

Overview:

Description: The Cabbage Stem Flea Beetle, scientifically known as Ceutorhynchus napi, poses a significant threat to cruciferous crops, especially cabbage and oilseed rape.

Detailed Appearance:

  • Size: Adult beetles are small, ranging from 2 to 3 mm (0.08 to 0.12 inches) in length.
  • Color: Typically shiny black or brown with elongated bodies.
  • Features: Flea beetles have enlarged hind legs, enabling them to jump when disturbed.

Life Cycle:

  • Egg: Eggs are laid in the soil near host plants.
  • Larva: Larvae feed on the roots and lower stem of the host plant.
  • Pupa: Pupation occurs in the soil.
  • Adult: Emerging as adults, they feed on the foliage and reproduce, completing the life cycle.

Identification of Crop Infection:

  • Leaf Damage: Adult beetles cause characteristic small, round holes in leaves.
  • Stem Damage: Larval feeding results in tunneling and damage to the stem's vascular tissue.
  • Plant Wilting: Severe infestations may lead to wilting and stunted growth.

Management Strategies:

  • Crop Rotation:

    • Rotate crops to disrupt the life cycle and reduce beetle populations.
    • Avoid consecutive plantings of cruciferous crops in the same field.

  • Early Planting:

    • Plant crops early to help them outgrow the vulnerable stage when beetle feeding is most damaging.

  • Trap Crops:

    • Introduce trap crops to lure and concentrate beetles away from main crops.
    • Remove and destroy trap crops regularly.

  • Biological Control:

    • Encourage natural enemies like parasitoid wasps and predatory beetles.
    • Consider releasing beneficial nematodes in the soil.

  • Chemical Control:

    • Apply insecticides if populations exceed economic thresholds.
    • Target treatments during the vulnerable stages of plant development.

Note: Integrated pest management (IPM) practices, combining various strategies, are effective in mitigating Cabbage Stem Flea Beetle damage. Regular monitoring and early intervention are crucial for successful pest management. Always adhere to recommended pesticide application guidelines and consider the potential impact on beneficial organisms in the ecosystem.