Cherry fruit sawfly

The cherry fruit sawfly (Hoplocampa cookei) is a member of the Tenthredinidae family within the order Hymenoptera. This pest is specifically known for its impact on cherry and plum production.

Adults are small insects, approximately 4–5 mm long, with a dark appearance. They emerge in early spring, precisely timing their life cycle with the blossoming stage of their host plants.

The larvae are cream-colored with brown heads and reach up to 10 mm in length. After feeding, they drop to the soil, where they create a cocoon to overwinter as prepupae.

The species has a univoltine life cycle, meaning it produces only one generation per year. This synchronization with the host tree makes the sawfly a highly specialized and dangerous pest for stone fruits.

Correct identification is crucial for effective management, as the damage caused by larvae often remains hidden inside the fruit until it is too late for corrective treatments.

The primary hosts for this pest include cherries, plums, and occasionally apricots or peaches. Larvae feed exclusively on the developing fruit, specifically targeting the seed and internal tissue.

Infested fruits frequently deform, cease to develop, and eventually drop from the tree. In severe infestations, the cherry fruit sawfly can cause significant economic losses by destroying most of the crop.

Feeding activity by the larvae leaves internal cavities that become prone to fungal and bacterial decay. This secondary damage renders any remaining fruit unsuitable for market sale or consumption.

The damage is particularly devastating for early-ripening varieties, as the larvae complete their development and exit the fruit before it even begins to show signs of maturity.

Orchardists often observe sudden fruit drops, which are a hallmark of an unchecked sawfly infestation that occurred earlier in the season during the initial fruit set.

The earliest signs of an infestation are minute scars on the sepals or the surface of the developing fruit, marking the exact spots where the female deposited her eggs.

As larvae begin feeding, they leave behind dark, powdery frass (excrement) around entry holes on the surface of the fruit, which is a key diagnostic indicator for growers.

A high rate of fruit drop shortly after the blossom petals have fallen is a major red flag. Examining these fallen fruits often reveals the presence of larvae inside.

If you split open a potentially infested fruit, you will find a yellowish-white larva with a distinct brown head. Soft, mushy fruit on the tree also indicates internal feeding.

Monitoring the adult population in the orchard using sticky traps during the blooming period is the most reliable way to gauge the pressure of the upcoming infestation.

Effective control begins with orchard hygiene, including the removal and destruction of fallen fruit that may contain active larvae before they burrow into the soil to pupate.

Chemical control should be implemented immediately after petal fall, targeting the window after egg hatching but before the larvae enter the fruit tissue to prevent internal damage.

It is essential to avoid applying insecticides during the peak flowering time to protect pollinators. Selecting selective, low-toxicity products is recommended for integrated pest management.

Tilling the soil in the orchard during autumn or early spring can disrupt the overwintering prepupae in their cocoons, significantly reducing the population for the next season.

• Use of yellow sticky traps for monitoring and mass trapping.
• Maintenance of healthy soil structures to manage moisture levels for larvae.
• Encouragement of natural predators, such as parasitic wasps and birds.