Cottony Cushion Scale

Subject: garden bug
Location: Sacramento CA, USA
February 16, 2014 6:20 pm
I found these strangers on my neighbor’s miniature roses. It is February now, and the location is Sacramento, CA, USA. They were on other plants, but seem to prefer roses. they are about the size of a large, fat grain of cooked rice. Picture P2140190 is on the miniature rose from above, and picture P2140192 is the underside of one of them. The white area is fibrous and kind of fluffy.
Signature: Lily Tee

Dear Lily Tee,
This looks like a Cottony Cushion Scale, Icerya purchasi, to us.  According to BugGuide, it is also called “Fluted Scale, Australian Bug, Australian Mealybug.”  This introduced species poses a major threat to citrus trees as well as many other cultivated plants.  BugGuide also notes:  “The white fluted part of the insect is an egg sac that can contain up to 1000 eggs. The insect is hermaphroditic, producing sperm that can fertilize its own ova, but in an alternate reproductive strategy it can also make winged males that can fertilize the female part of other individuals.  When it first appeared in the w. US it was a major pest of Citrus crops. In CA, around 1889, it was an early success story for biological control by beneficial ladybird beetles (Rodolia cardinalis). (Full story) The control was so successful that in 1893 a Florida nurseryman asked for some of the beneficials to be sent to FL, to test as a control for other scale insects. The scale was included in the shipment as food for the beetles, and thus accidentally introduced to FL citrus.”  Your images are quite excellent in detail.

Thank you so much for your quick response! I will get my friend some lady bugs (and some for me as well).
Lily