Four-wing Saltbush, Atriplex canescens
on the left with a new and on the right an old infestation
of Irregular Wax Scale, Ceroplastes irregularis
(On the left, my dog in the background, Caninous DixieBellious v. Cates)
I've wondered about this orange stuff — now I know it's scale — for some time. So far, I've only noticed it on four-wing saltbush where sometimes it almost completely covers its host. I've also noticed that infestations are not sporadic, but rather grouped together, attacking most of the saltbush in a particular area.
There are about 8,000 varieties of scale, a kind of insect that usually is parasitic, sucking sap from its plant host. It is the female that we see, immobile, covered here in her waxy protection. The male has wings and can fly, but is typically short-lived, sometimes not even feeding in its lifetime. Generally scales are considered a pest because at some point their infestation will damage branches, or even kill their host.
Not always entirely a pest, though. The most well-known scale is probably cochineal that grows on prickly pear, and long before the infamous Red #5, was a valuable source of a much-coveted red dye.
While not as famous as its cousin, the irregular wax scale also was used ingeniously by Native Americans. The wax from the insect's outer covering was used to waterproof baskets, as a mastic on tool handles and bows, and even as chewing gum.
Out in the field one day, I decided to see for myself what was under that bumpy, cream-colored crust. I picked off a single insect. The waxy outer crust surprisingly came off with little effort, but it was difficult not to damage the inner creature, who exuded some reddish fluid under the pressure. It was apparent she was very definitely living, at least up until I plucked her from her food source. At another time, I had tried to see what was up with this crusty stuff, but then I must have worked with an older, dying infestation; the crust then was crumbly (I described it as "like granola") whereas the wax from this specimen was firm, but soft.
Not the prettiest insect I've ever seen. Still, I'd like to take some home to look at closer with a good light and magnifying glass. And I'd like to experiment with the wax as basket waterproofing since I've been making some yucca baskets. I confess that after seeing the scale insect inside, I doubt I will ever experiment with it as chewing gum!
Links (Four-wing Saltbush):Links (Scale insects):
- Dave's Garden gardeners discuss the Four-wing Saltbush. It is native to Texas, evergreen, and all parts of the plant are edible. They say the leaves taste salty. I found it most interesting that its burnt leaves can be used as a leavening agent! Some more experiments for another day.
- A general article about the FWSB found on the DesertUSA site.
- FWSB is used as food and shelter by a large number of animals, per this Suite 101 article.
- General article about scale insects on Wikipedia.
- A short article with photos of irregular wax scale and ortheziid mealybug from The Colorado State Extension Agency.
- An incredible number of photos (more than 5800!) of scale from the ForestryImages.org site, a joint project of of The Bugwood Network and USDA Forest Service, the University of Georgia - Warnell School of Forestry and Natural Resources and College of Agricultural and Environmental Sciences - Dept. of Entomology.
- Can't get enough of scale insects? You just might need this 1993 book by Yair Ben-Dov, A Systematic Catalogue of the Soft Scale Insects of the Worldhe Scale Insects. At over 500 pages and $200, it's probably only for the very serious. However, it's available with a limited preview on Google books.
- On the other hand, you can download all 19 pages in pdf of The Chemistry, Archaeology, and Ethnography of a Native American Insect Resin from University of California's eScholarship. Or this interesting 9 page pdf article about extracting lac (shellac) Notes on Creosote Lac Scale Insect Resin as a Mastic and Sealant in the Southwestern Great Basin by Mark Q. Sutton.
