62.047 BF1461  –  Pyralidae –  Phycitinae – Assara terebrella – Dark Spruce Knot-horn – (Zincken, 1818) Adult Micro:  CAT 2 – Confusion Species –       PDF Icon – click for General Verification Guidelines  |   PDF Icon – click for Specific Verification Guidelines
Brown –  Significant Record / Very Rare / Vagrant    
Taxonomy:   Micro   >>  Pyralidae  >> Phycitinae
ID Difficulty:  green  – easy to identify, generally distinctive and unlikely to be confused with other species.
ID pointers: A distinctive moth with the forewing a reddish-brown ground colour with 2 discal spots, conspicuous whitish markings and a zig-zag cross-line at about half way and another at the inner wing apex.
Distribution:  (First record: 26 June 2021 at Breaston )  –  (Last record: 18 July 2025 at Cromford )  –  One record from Breaston 26th June 2021 , first record for VC57 & Derbyshire.(iRecord) . The second record was from Cromford on 18th July 2025.
Flight Period: June /  July /  August /  Moth Activity: Cathemeral   – and is attracted to light Photographed: Yes –  Photographed By: Steve Thorpe, Clive Ashton   © All Rights Reserved
*** Last updated on 26 July 2025 by TD ***
Wingspan: 22-25mm
Food Plant: Found in Spruce plantations, particularly Norway Spruce
Last Recorded Year: 2025
First Recorded Year: 2021
Last Recorded By – Clive Ashton
Last Recorded General Area – Cromford

IMAGES BELOW:  

Breaston (2021) 1st VC57 & Derbyshire record – Steve Thorpe© / 2nd VC57 & Derbyshire, Cromford (2025) Clive Ashton©

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Distribution Map for Assara terebrella

Found 2 records
    ↳ 1 from After 2025
    ↳ 1 from 2020 - 2024
    ↳ 0 from Before 2020

If the Map Layers function fails, just refresh the page and it should be OK after. Use the +- zoom on the top left, or on a tablet, use two fingers to zoom. Remember, the last layer you ticked is the one which displays the popup information - they sit on top of each other - de-select then re-select, to see the popup values.

******* Choose ONLY one at a time, of either Monad, Tetrad or Hectad Distribution - each has it's own set of data. Also, the distribution maps cover ALL recorded data. *******

Bedrock Geology ** indirectly affects moth distribution by influencing the type of habitat and food plants available in an area. In turn, this may affect the types of moths that can thrive, or where they can most likely be found.

Land-cover * shows the variety of land-cover within the VC57 area, based on the CORINE (Coordination of Information on the Environment) forty-four thematic classes of land-cover. This will show, to a greater or lesser degree, the number and variety of moths found in different land-cover types. The UK continues to operate within the Copernicus programme, with the UK Centre for Ecology & Hydrology (UKCEH) providing Corine Land Cover (CLC) datasets for the UK and its territories.


NBN Atlas UK Distribution for – Assara terebrella

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Note – the NBN Atlas datasets are listed in the map below and vary in their currency (uptodateness) – however, the map does give a general indication of the moth's distribution across the UK.

Visit NBN Site


Monthly Records By Year: Assara terebrella
( data includes both Larvae and Adult Stages )

Monthly Counts By Year: Assara terebrella
( data is based on 'Adult' stage records only. )


First/Last Recorded Dates: Assara terebrella
Adult-only & Anything [Larvae, Pupae, Adult, Mines]

Shading shows moth presence between dates

Click the colour discs below to Select/De-select as Required

Recordings By Year: Assara terebrella
( All data includes both Larvae and Adult Stages )
Annual Growth Rate (AGR): Assara terebrella
AGR: 0%   |   Total % Change: 0%


CUSUM Analysis: Assara terebrella
About this chart: CUSUM (Cumulative Sum) charts track long-term trends in moth populations [ filtered by 'Adult' and 'Mine' life stages ] by showing whether each year’s counts are above or below the historical average. Even small shifts build up over time, making trends of growth, stability, or decline easier to see. CUSUM highlights trend-consistency — asking: “Across the years, have moth counts mostly stayed above or below average?”
The data sample has 24 gap year/s here (zero records) between 2000 and 2025. The moth may have been present in those gap years, but no data was available. Too many year-gaps may exaggerate or skew the chart.

Counts for the current year (2025) are pro-rated based on data available up to month 7 (July) to provide a full-year equivalent.

Purple line rises = years better than average; falls = years worse than average.
Peak (best year) Trough (worst year) Growth periods Decline periods
Population peaked around 2025, reaching above average levels. The lowest population point occurred near 2021, showing a significant decline.

What the Y-axis "Cumulative Deviation" means: Cumulative Deviation shows the running total of how each year’s moth population count differs from the long-term average. i

Hectad (10kmx10km) Coverage: Assara terebrella
( data includes both Larvae and Adult Stages )

Flight Periods – Indicative –vs– Recorded Data
Assara terebrella
( data includes Adult Stage only )

Flight Period chart – the grey hatched area above, which can cross one or more months, pictorially represents the best guess we have for this moth's flight periods [month/s]. The coloured lines represent the actual months seen in flight, from site observation records received between 2020-2025.

Records Behind the Map and Charts - Assara terebrella – 2 records available

Listed by Year - descending - scroll across to see all table columns

TaxonSite NameTetradYearDateCountStageSource
Assara terebrellaupper cromford gardenSK25Y202518/07/20251adultvc57_irecords_extract
Assara terebrellaWoodland AveSK43R202126/06/20211adultvc57_irecords_extract

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