• Definition

  Saissetia oleae is a soft-bodied hemipteran mealybug , which mainly attacks olive trees but also citrus fruits and other plants. It attaches itself to twigs, leaves and sometimes fruits, where it sucks the sap of the plant, causing a general weakening. Its honeydew promotes the development of sooty mold, reducing photosynthesis and fruit quality.

  Development Lifecycle

  1. 1. 1. 1. Larvae : Young larvae (called “crawlers”) move to find a feeding site. They go through 3 larval stages before becoming adults.

           2. Reproduction : largely parthenogenetic (without mating).

           3. Cycle length : several months; 1 to 2 generations per year depending on climatic conditions.

           4. Survival : Adult females overwinter on twigs and continue to feed in mild winters.

  Symptoms

  • • • Presence of bulging and dark brown mealybugs on twigs and leaves.

      • Weakening of the plant by sucking the sap.

      • Production of abundant honeydew → development of black sooty mold on leaves and fruit.

      • Decrease in photosynthesis, slowed growth, leaf drop.

      • Depreciation of fruit : fouling, blackening, loss of commercial quality.

      Contributing factors

  • • • • Mild and humid eco-climatic conditions, especially in coastal areas.

        • Lack of natural control (predators or parasitoids destroyed by insecticides).

        • Unaerated orchard, dense or poorly maintained plantings.

        • Presence of ants that protect mealybugs from their natural enemies in exchange for honeydew.

Preventive control

• Regular monitoring of young mobile stages (larvae) in spring and summer.
• Pruning of infested parts and removal of plant debris.
• Avoid systematic insecticide treatments that destroy beneficial insects.

Biological control

• Encouragement of natural enemies:
  • Lady Beetles (e.g., Chilocorus bipustulatus)
  • Parasitoid Hymenoptera
• Reduction of ant populations, which interfere with the action of beneficial insects.

Chemical control

• Treatment at the young larval stage with suitable products (mineral oils, specific insecticides).
• Application of white oils during winter dormancy to suffocate adults.

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