**Quince Curculio** (*Conotrachelus crataegi*) is a native weevil (snout beetle) that is a serious pest of **quince**, as well as hawthorn, apple, and pear fruit. The conflict is severe fruit deformation and contamination: the female beetle punctures the developing fruit to lay eggs, leaving a tell-tale **crescent-shaped scar**. The larvae then tunnel and feed inside the fruit, causing it to become **lumpy, inedible, and drop prematurely**.
Taxonomy and Classification
Quince Curculio belongs to the order Coleoptera (Beetles), family Curculionidae (Weevils). They undergo complete metamorphosis. The destructive larva is a legless grub that feeds for several weeks inside the fruit before exiting to pupate in the soil.
Physical Description
Adult Weevil is small, 1/4 inch long.
- **Appearance (Key ID):** Grayish-brown, mottled beetle with the characteristic **long, slender snout** (rostrum) used for boring into fruit.
- **Larva (Key ID):** White, C-shaped, legless grub found tunneling inside the fruit flesh.
- **Damage Sign (Key ID):**
- **Crescent Scar:** Tiny, crescent- or banana-shaped wounds on the skin of the fruit (oviposition site).
- **Deformation:** Lumps and bumps on the surface of the growing fruit where the larva is feeding.
- **Wormy Fruit:** Internal tunneling and contamination visible upon cutting the fruit.
- **Conflict:** Fruit destruction and contamination.
Distribution and Habitat
Quince Curculio is found across eastern North America. Their habitat is the foliage and developing fruit of its various host trees. They overwinter as pupae or adults in the soil beneath the host tree.
Behavior and Conflict
The conflict is dominated by the beetle’s synchronized emergence.
- **Timing:** The adults emerge from the soil at a specific, predictable time, typically just after the petals fall from the host tree, making precise treatment timing possible.
- **Larval Seclusion:** Once the larva is inside the fruit, it is protected from contact insecticides, meaning control must target the adult beetle or the newly laid egg.
- **Reinfestation:** Leaving infested, dropped fruit on the ground allows the larvae to complete their development and ensures a robust population the following year.
Management and Prevention
Control is integrated pest management (IPM), with a crucial focus on sanitation and timing.
- **Remove Fallen Fruit:** Collect and destroy all dropped or infested fruit immediately. Do not compost it, as the grubs will survive.
- **Timing:** Apply a registered orchard insecticide 7 to 10 days after the petals have fallen (petal fall) to target the newly emerged adult weevils before they lay eggs. Repeat applications may be necessary based on monitoring.
- Use jarring boards or traps to monitor adult weevil emergence from the soil, informing the precise timing of sprays.
Conservation and Research
Quince Curculio is managed as a high-priority fruit pest. Research focuses on developing effective pheromone lures for monitoring, optimizing the timing of non-chemical controls, and evaluating the impact of beneficial parasitic wasps on larval populations.