White louse scale

Unaspis citri

Overview:

Type of Pest: Unaspis citri, commonly known as Citrus Snow Scale, is a scale insect species that affects citrus trees and other ornamental plants.

Physical Characteristics:

  • Adult Females: Flat, oval-shaped, and covered with a waxy covering.
  • Color: Female scales vary in color, ranging from white to pale yellow or light brown.

Life Cycle:

  • Egg Stage: Eggs are laid beneath the female's waxy covering.
  • Crawler Stage: Newly hatched nymphs, known as crawlers, move to find feeding sites.
  • Adult Stage: Nymphs settle and develop into immobile adult scales.

Identification of Crop Infestation:

  • Waxy Covering: Females are covered in a protective waxy layer that resembles snow or scale.
  • Yellowing and Wilting: Infested plants may show symptoms of yellowing, wilting, and reduced vigor.
  • Sticky Honeydew: Scales excrete honeydew, leading to the growth of sooty mold on leaves.

Management Strategies:

  1. Cultural Practices:

    • Pruning: Remove heavily infested branches to reduce scale populations.
    • Sanitation: Remove and destroy fallen leaves and debris to eliminate overwintering sites.

  2. Biological Control:

    • Natural Enemies: Encourage natural predators such as lady beetles, predatory beetles, and parasitic wasps.
    • Beneficial Insects: Release or conserve beneficial insects that feed on scale insects.

  3. Horticultural Oil:

    • Summer Oil Sprays: Apply horticultural oil during the summer to suffocate scales.
    • Dormant Oil Sprays: Use dormant oil during the tree's dormant season to control overwintering scales.

  4. Insecticidal Soaps:

    • Spray Application: Insecticidal soaps can be effective against scales when applied directly.
    • Repeat Treatments: Repeat applications as needed, especially for crawler stages.

  5. Systemic Insecticides:

    • Soil Drench: Apply systemic insecticides as a soil drench for uptake by the plant.
    • Foliar Sprays: Apply systemic insecticides directly to the foliage for scale control.

  6. Ant Control:

    • Ant Management: Control ant populations, as they may protect scales from natural enemies.
    • Ant Baits: Use ant baits to reduce ant activity.

Note: Citrus Snow Scale can weaken and damage citrus trees, leading to reduced fruit production. Integrated pest management (IPM) practices that combine cultural, biological, and chemical control methods are essential for effective scale management. Always follow recommended guidelines and consider the potential impact on beneficial insects and the environment.