Apple Curculio: Appearance, Territory, Damage and Life Cycle

Latin Name: Anthonomus Quadrigibbus

Appearance: A. Quadrigibbus is well known as a rare but important insect pest of commercial apple, pear, saskatoon, and maybe sour cherry orchards. Apple curculio is similar to plum curculio, but the former is reddish-brown in color and has a longer, thin nose, whilst the latter is darker in color and has a shorter, stockier snout. Larvae are white or cream in color, have no legs, are curled, and appear to be strong. The sides of the skull are firmly rounded, and the head is light brown.

Hosts Plants: Saskatoon Serviceberry and Apple

Territory: North America and Europe

Damage Insect Cause: A. Quadrigibbus principal harm is connected with eating and oviposition. The end result is malformed, knotty, and undersized fruit. Feeding and oviposition punctures, in general, halt development and result in depressions and the creation of hard tissue. Tiny punctures in the skin of the fruitlets are frequently the first signs of harm. Feeding punctures are typically 0.5 mm in diameter and 2-3 mm in depth. Weevils carve out chambers under the punctures for eating or oviposition. If for the latter, they are sealed with a frass pellet. These punctures are left at the bottom of funnel-shaped pits as the fruit expands, causing the fruit to become deformed.

The oviposition punctures are broader towards the bottom, but the feeding punctures are relatively parallel-sided; yet, the two types of punctures are nearly indistinguishable on the fruit’s surface. In ripe fruit, larvae, pupae, and adults can be discovered. The next generation of adults feeds on mature fruit (apples in particular), resulting in collapsing brown patches that can cluster to create regions up to 2.5 cm in diameter. Rots and other pests can enter through small holes. Fulton provided drawings and/or images of adult feeding punctures on fruit, larval feeding damage within fruit, and seed damage.

Life History and Habits: The apple curculio has four stages of development: egg, larva, pupa, and adult. Eggs are laid in a tiny, crescent-shaped chamber beneath the fruit’s surface. The eggs develop into small, legless, pale larvae after about a week.