Icerya purchasi
In 3 days ~10% in a week ~30%
Icerya purchasi (common name: cottony cushion scale) is a scale insect that feeds on more than 80 families of woody plants, most notably on Citrus and Pittosporum. Originally described in 1878 from specimens collected in New Zealand as pests of kangaroo acacia and named by W.M. Maskell "after the Rev. Dr. Purchas who, [he] believe[d], first found it", it is now found worldwide where citrus crops are grown. The cottony cushion scale originates from Australia.
This scale infests twigs and branches. The mature hermaphrodite is oval in shape, reddish-brown with black hairs, 5 mm long. When mature, the insect remains stationary, attaches itself to the plant by waxy secretions, and produces a white egg sac in grooves, by extrusion, in the body which encases hundreds of red eggs. The egg sac will grow to be two to three times as long as the body. Newly hatched nymphs are the primary dispersal stage, with dispersion known to occur by wind and by crawling. Early stage nymphs feed from the midrib veins of leaves and small twigs, and do the bulk of the damage. At each molt, they leave at the old feeding point the former skin and the waxy secretions in which they had covered themselves... Wikipedia →
| # | Park | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Garden Route National Park | 🇿🇦 South Africa | |
| 2 | Table Mountain National Park | 🇿🇦 South Africa | |
| 3 | Galápagos Islands | 🇪🇨 Ecuador | |
| 4 | Everglades National Park | 🇺🇸 United States |
| # | City | Country | Daily sighting probability |
|---|---|---|---|
| 1 | Naples | 🇮🇹 Italy | |
| 2 | Pretoria | 🇿🇦 South Africa | |
| 3 | Nairobi | 🇰🇪 Kenya | |
| 4 | Barcelona | 🇪🇸 Spain | |
| 5 | Cape Town | 🇿🇦 South Africa | |
| 6 | Nagoya | 🇯🇵 Japan | |
| 7 | Guatemala City | 🇬🇹 Guatemala | |
| 8 | Johannesburg | 🇿🇦 South Africa | |
| 9 | Athens | 🇬🇷 Greece | |
| 10 | Valencia | 🇪🇸 Spain |
Rare
Under 5% of wildlife watchers report a Cottony Cushion Scale sighting in Sacramento on a given day, based on 17 verified sightings from GBIF citizen-science data. It is the 171st most-seen of the 386 insects we can rate there. Over three days the chance rises to about 10%, and over a week to about 30%, if each day is a fresh chance.
April and December–February
In those months about 10% of wildlife watchers report a Cottony Cushion Scale in Sacramento on a given day, against under 5% in March and May–November, the lowest months. Those are among Sacramento's wettest months, with about 90 mm of rain a month against almost none in July.
Between 8 and 11 am
Across all the parks we cover, that three-hour window holds the most Cottony Cushion Scale sightings with a recorded time, and about 9 in 10 of them come between 6 am and 6 pm: it is a daytime animal.
27th of 45
Of the 45 cities where we can rate Cottony Cushion Scale sightings, Sacramento ranks 27th at under 5%. The best odds are in Naples (Italy, about 10%), Pretoria (South Africa, about 10%) and Nairobi (Kenya, about 10%).
Same order: Hemiptera
The closest relatives of the Cottony Cushion Scale that you can see in Sacramento (order Hemiptera, True Bugs, Hoppers, Aphids, and allies) are Leptoglossus zonatus (about 20%), Western Boxelder Bug (about 20%) and Leafhopper Assassin Bug (about 20%), with each one's daily chance of a sighting.
GBIF citizen-science records
It is estimated from how often the Cottony Cushion Scale is recorded against all the insects logged in Sacramento (17 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.
