Bacchus weevil

The Bacchus weevil (Rhynchites bacchus) is a destructive species of weevil (Curculionidae) within the order Coleoptera. It is easily identifiable by its metallic, reddish-purple or coppery sheen, which stands out against the green foliage of trees and garden plants.

This pest is highly polyphagous, meaning it feeds on a wide range of hosts. While it is a primary threat to apple trees, it also causes significant damage to hops, fodder beets, cabbage, peppers, tomatoes, eggplants, and peas. In gardens with diverse crops, the weevil can switch between hosts depending on the season.

The life cycle begins with overwintering adults emerging in the spring as buds break. After feeding on buds and young leaves, the females lay eggs into young fruits. A critical part of their behavior is the intentional wounding of the fruit stem, which causes the infested fruit to fall to the ground, providing an ideal environment for larval development.

Damage caused by the Bacchus weevil is severe. It manifests as deep, crater-like holes in fruit, which often weep gum or become infected with rot. Aside from fruit damage, the beetles bite buds and young shoots, significantly stunting plant growth. If left unchecked, they can decimate a large percentage of the orchard's annual production.

Control strategies must be integrated to be effective. Cultural practices include the immediate removal and destruction of fallen fruits to prevent larvae from entering the soil for pupation. Additionally, tilling the soil around trees can destroy overwintering sites. Chemical control involves the application of appropriate insecticides during the pre-blooming and post-blooming stages to reduce the adult population.