Spotted tentiform leafminer

Definition

A small moth (Phyllonorycter blancardella, Gracillariidae) whose larvae mine the leaves of apple, crabapple, and related rosaceous trees, creating distinctive raised, tent-like mines with scattered dark frass spots on the upper leaf surface. The mine's puffy, blistered appearance results from larval feeding between the upper and lower epidermis, with silk drawing the layers together. Native to Europe and introduced to North America, it is a familiar pest in orchards and a model organism for studies of leafminer population dynamics and parasitoid communities.

Etymology

From the dark frass spots visible on the mine surface and the tent-shaped, inflated form of the blotch mine.

Example

In Michigan apple orchards, parasitoid wasps such as Pholetesor ornigis often suppress spotted tentiform leafminer populations below economic injury levels, making biological control a viable alternative to insecticide sprays.

Synonyms

• Phyllonorycter blancardella

Related Terms

• leaf miner
• Gracillariidae
• Phyllonorycter
• serpentine leafminer
• blotch mine
• Frass
• Parasitoid
• Biological control

Usage Notes

The common name refers specifically to P. blancardella; other Phyllonorycter species on apple (e.g., P. crataegella, the brown apple leafminer) create visually similar mines and require microscopic examination or rearing to distinguish. The term "tentiform" describes the mine architecture—silk-contracted, tent-shaped blotch—not the adult moth. In orchard management, economic thresholds are typically expressed as mines per leaf rather than larval counts because mines persist after larvae exit or are parasitized.