Japanese fruit lecanium

The Japanese fruit lecanium (Eulecanium kunoense) is a scale insect belonging to the family Coccidae, order Hemiptera. It is a significant pest of fruit trees that feeds by extracting sap, which leads to reduced plant vigor, stunted growth, and in cases of heavy infestation, branch dieback.

This pest primarily attacks a wide range of fruit-bearing trees, particularly those in the Rosaceae family. Common hosts include plum, apricot, peach, cherry, apple, and pear trees. The insects are typically found clustering on the branches and twigs, often blending in with the bark.

The life cycle of the Japanese fruit lecanium consists of one generation per year. The insect overwinters as second-instar nymphs on the bark of twigs and branches. In early spring, they resume feeding, mature into adults, and begin producing eggs in late spring or early summer beneath the protective cover of the female body.

The damage caused by this pest is twofold: direct sap loss and the production of honeydew. Honeydew secretion coats the foliage and fruit, promoting the growth of sooty mold. This fungus blocks sunlight and inhibits photosynthesis, which can significantly lower the quality and yield of the harvest.

Effective management and control strategies are essential to protect the orchard:

• Pruning and destroying heavily infested branches during the dormant season.
• Application of horticultural dormant oils in early spring to smother overwintering nymphs.
• Monitoring for crawler emergence in early summer to time the application of contact or systemic insecticides.
• Promoting biological control through the conservation of predatory lady beetles and parasitic wasps.