Copper weevil

The copper weevil (Rhynchites cupreus) is a beetle belonging to the Curculionidae family, known for its distinct metallic appearance and pest status in orchards.

Adult beetles are small, measuring approximately 3.5 to 4.5 mm in length, and are characterized by a striking copper-red body with a metallic sheen.

The body is covered with fine, sparse hairs, and they possess a typical snout-like rostrum used for feeding on plant tissues and drilling into fruits.

Larvae are white, legless, and curved, with a brown head capsule. They develop hidden inside the seeds of stone fruits, shielded from external environment.

This species undergoes a complete metamorphosis, including egg, larval, pupal, and adult stages, with adults typically overwintering in the soil.

The pest primarily targets stone fruit trees, including plums, cherries, sour cherries, mirabelles, and apricots, causing significant economic loss.

Adult beetles feed on young leaves, buds, and green fruit, creating small feeding punctures that can lead to scarring and early fruit drop.

The most severe damage is caused by the larvae, which burrow into the fruit to consume the seed kernel, preventing proper fruit development.

Infested fruits often exhibit "gummosis" or sap flow around the puncture sites, turn yellow, and fall prematurely to the ground.

In cases of high infestation, a significant portion of the crop can be destroyed, rendering the harvest unsuitable for commercial use.

Adults emerge from their overwintering sites in the soil during spring, synchronized with the budding and flowering of host stone fruit trees.

Peak activity occurs during the blossoming and initial fruit-set phases, when the beetles actively mate and feed on tender fruit tissues.

Oviposition takes place when the young fruit reaches the size of a pea, as the female uses its rostrum to bore a hole for the egg into the pit.

Larval development occurs throughout June and July, after which the mature larvae exit the fruit and drop to the soil for pupation.

The new generation of adults usually remains in the soil through the remainder of the summer and winter, completing one life cycle per year.

Early signs include tiny, dark puncture marks on the surface of young developing fruit, often accompanied by droplets of hardened sap (gum).

Widespread premature fruit drop starting in early summer is a primary field indicator of larval infestation within the orchard.

Dissecting the dropped fruit reveals a damaged or hollowed-out stone, which serves as a definitive confirmation of the pest's presence.

Visual observation of the canopy in the early morning can reveal beetles resting on foliage, as they tend to be less active during cooler hours.

Deformed fruit with necrotic spots and reduced size are common visual indicators of a damaged crop caused by previous larval feeding.

Sanitation is the most effective management practice; collecting and destroying all fallen fruit prevents larvae from migrating to the soil to pupate.

Cultivation of the soil beneath the canopy during late summer or autumn disrupts the pupal stage, leading to significant mortality of the pest.

Insecticide applications should be timed during the pre-bloom or petal-fall stages to control the adult population before egg-laying occurs.

On smaller scales, manual shaking of trees onto a white sheet in the morning is a viable method to remove and dispose of adult beetles.

• Consistent removal of infested fruit
• Soil tillage to disrupt lifecycle
• Targeted chemical application at key phenological stages