Seq # 185020020

Dialectica scalariella (Zeller, 1850) Species

Last modified: Oct. 18, 2023, 10:28 a.m.

New species to Belgium in 2023 in LI and NA.


Family: Gracillariidae > Subfamily: Acrocercopinae > Genus: Dialectica > Species: Dialectica scalariella
Vernacular names
Echium Leaf-miner, Bugloss slender (EN)




Wingspan 9–11 mm. The forewings of the adult moth have a brown front half, and a white rear half, with a wavy line separating the halves. The head and thorax have white dorsal patches.

Museum specimens

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Specimens in nature


It attaches opalescent eggs to the undersurface of host leaves. They hatch in 4–6 days.

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The yellow larvae have a brown head and no obvious prothoracic plate.


Mine usually lower-surface, not often upper-surface.


The inner and outer cocoon are both conspicuously white, with the inner cocoon broadly ovate to roundish, rarely with attenuate ends, and relatively large, often nearly filling the outer cocoon.
At emergence the pupa forces it way through both layers of the cocoon and the epidermis of the leaf, protruding from the mine.


The larvae destroy leaves by forming large bulbous blotch mines. The first three instars enlarge the mine gradually, forming a transparent lens-like blotch mine in which all tissue between the two epidermal layers has been consumed, the epidermis eventually turns brown. Within the mine, the final instar larva constructs a white cocoon in two layers.
It overwinters in the mine as alarva or a pupa.

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Flight periods

The species shows a great deal of flexibility in its development with a wide variation in the number of generations (5 to 7) each year and their timing, depending on location. This is likely to be strongly dependent on temperature, which affects the speed of development and whether diapause is required.
In our temperate climate it is assumed that the species has two extended generations a year. The adults can be seen from April/May and again from August towards October.

Observed on

Host plant (species):
Echium vulgare

The caterpillar lives on Echium vulgare, which is the most commonly used food plant. Also but less on other Boraginaceae.

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Areas with the food plant and preferably in warmer places.

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