Fiorinia externa
In 3 days ~10%
Fiorinia externa, the elongate hemlock scale, was accidentally introduced into North America from Japan and is now established in most parts of the north-eastern U.S. It has become a serious pest of hemlock (Tsuga) and some related conifers from the family Pinaceae. Dense colonies of the scale insect result in yellowing, shedding of leaves, dieback and occasional tree death.
Fiorinia externa is native to Japan and southern China. It was first reported on Tsuga from New York state in 1908. Compared to other invasive insects, it has spread slowly across the north-eastern U.S. and has reached Georgia in the south, as well as Michigan, Kentucky and Tennessee further west.
While F. externa has not been confirmed to be established in other areas, it is regarded as being of quarantine concern. For example, it has been recorded from other parts of North America like California and Florida on host cuttings. In England, it was reported on a single fir tree imported from the U.S., but subsequently died out on that tree.
The adult female of Fiorinia externa is about 1 mm long. The scale cover of the second instar female is elongated, around 1.5 mm long and has... Wikipedia →
| # | Park | Country | Daily sighting probability |
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More parks will be added in future updates.
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Boston | 🇺🇸 United States | |
| 2 | New York City | 🇺🇸 United States |
Rare
Under 5% of wildlife watchers report an Elongate Hemlock Scale sighting in New York City on a given day, based on 11 verified sightings from GBIF citizen-science data. It is the 1034th most-seen of the 1623 insects we can rate there. Over three days the chance rises to about 10%, if each day is a fresh chance.
Any time of year
In every month with enough records, under 5% of wildlife watchers report an Elongate Hemlock Scale in New York City on a given day, so our monthly data shows no clear season.
Among the best
Of the 2 cities where we can rate Elongate Hemlock Scale sightings, New York City ranks 2nd at under 5%, level with the leaders once rounded. The best odds are in Boston (United States, under 5%).
GBIF citizen-science records
It is estimated from how often the Elongate Hemlock Scale is recorded against all the insects logged in New York City (11 verified sightings), calibrated against known sighting rates. Figures are rounded to the nearest 10% because citizen-science data supports honest approximations, not decimals, and months with records from fewer than five people show "—". How it works.
