Cherry slug sawfly

Eriocampoides oishii is a member of the Tenthredinidae family within the order Hymenoptera. Known as a significant pest of stone fruit trees, this insect species has a specific morphology and behavioral pattern that distinguishes it from other common sawflies. Understanding its biology is essential for maintaining tree health in commercial and home orchards.

The primary host plants for this pest include a variety of species from the Prunus genus, such as cherries, plums, and occasionally pears or hawthorns. The larvae, often called "slugs" due to their slimy appearance, feed exclusively on the upper surface of the leaves, consuming the green tissue while leaving the leaf veins and the lower epidermis intact.

The lifecycle consists of several generations per year. The adult females deposit eggs into the leaf tissue, and upon hatching, the larvae immediately begin their feeding activity. Their slimy coating is an evolutionary adaptation that protects them from desiccation and predators. Once the larvae reach maturity, they drop to the soil, where they pupate and remain until the next generation emerges.

Damage caused by this sawfly is highly recognizable as leaf skeletonizing. When infestation levels are high, the entire canopy can appear scorched or brown as the trees lose their photosynthetic capacity. This premature defoliation significantly stresses the trees, reducing their ability to store carbohydrates for winter, which eventually leads to stunted growth and reduced yields in subsequent seasons.

Integrated Pest Management (IPM) is the most effective approach for controlling this pest. Cultural practices like soil cultivation under the canopy can disrupt the lifecycle by exposing pupae to predators and environmental extremes. If necessary, chemical control using targeted insecticides should be applied during the early larval stages, ensuring that the timing coincides with the peak of egg-hatching for maximum impact.

• Regular scouting for skeletonized leaves and presence of slug-like larvae.
• Application of selective insecticides during early larval development.
• Soil tilling around the base of trees in autumn to reduce overwintering pupae.
• Encouraging natural predators such as parasitic wasps and birds.