Cottony camellia scale

First described in 1870 by Westwood, the cottony camellia scale, Pulvinaria floccifera (Westwood), shows up most commonly on holly in PNW nurseries and landscapes. It does have a wider host range (at least 35 plant families according to Scalenet) including its namesake camellias, English ivy, euonymous, hydrangea, maple, mulberry, pittosporum, rhododendron and the host by which it is also known, cottony yew scale.

According to the IPM alert database, egg hatch (eclosion) occurred approximately 7/3/2011 and 6/23/2009. This is a key time to control the crawler stage, which is very vulnerable to a range of "softer" pesticides include insecticidal soaps, horticultural oils, and insect growth regulators. Only one generation per year has been noted in the Pacific Northwest.

It has been reported that a 2% rate of oil (versus 1% rate) applied during the dormant stage works well.

Systemic insecticides: Fall timing of imidacloprid gives time for that systemic insecticide to move through the plant to the target tissue by spring. Dinotefuran (Safari) moves more quickly in plant tissue and can be used in the spring. Orthene is reported to have efficacy on this scale as well when used during the dormant stage.

Useful links:

LivingWithBugs.com: Cottony camellia scale

Cottony camellia scale. University of Maryland Landscape Problem Solver

Cottony camellia scale ovisac on holly

Photo: Rosetta

Multiple ovisacs on holly

Photo: Ken Gray

Cottony camellia scale female and developing ovisac

Photo: Ken Gray

Ovisac with eggs exposed

Photo: Ken Gray

Closeup of eggs

Photo: Rosetta

Cottony camellia scale crawlers emerging

Photo: Rosetta

Close up of cottony camellia scale nymph

Photo: Jim Young, OSU

Page last modified 3/13/12