Apple sawfly

The apple sawfly (Hoplocampa chrysorrhoea) belongs to the order Hymenoptera and the family Tenthredinidae. This insect is a significant pest of apple trees, known for its ability to cause severe economic damage to fruit yields if left unmanaged during the critical phases of tree development.

The primary host for this pest is the apple tree. While it is most frequently associated with apple cultivars, it can occasionally impact pear trees. The damage primarily occurs in the young fruitlets, where the larvae feed during the initial stages of fruit growth.

The biological cycle of the sawfly consists of a single generation per year. The insect overwinters as a larva within a cocoon in the soil. Adults emerge during the apple blossom period. After mating, females deposit eggs into the sepals of the flowers, ensuring the larvae have immediate access to food upon hatching.

The damage caused by the larvae is distinct: they tunnel into the fruitlet, creating winding paths and causing the fruit to exude sap. Infested fruitlets often turn black, wither, and drop prematurely. A single larva can damage multiple fruitlets as it moves from one to another to complete its development.

Effective management requires a combination of monitoring and intervention. Chemical control is most effective when applied immediately after petal fall, targeting the larvae before they burrow deep into the fruit. Additional cultural practices include:

• Cultivating the soil in autumn to disturb overwintering sites.
• Monitoring adult activity using white sticky traps.
• Removing and destroying infested fruitlets to break the life cycle.