Common name

Cottony hydrangea scale

Field characters

Body usually circular; relatively flat in cross section; body yellow or light brown on young females, dark brown in older females; without obvious wax covering; ovisac produced beneath and behind female, convex, broadly and shallowly grooved, white, flocculent, about 2 or 3 times length of body. Occurring on leaves and stems; oviposition is normally on twigs. Males mentioned by Canard (1969). Eggs laid inside ovisac.

Validation characters

More than half of marginal setae acute, remaining setae weakly fimbriate; without submarginal tubercles; each anal plate with 3 apical setae and 1 subdiscal seta; with 2 or 3 subapical setae on each plate; anal fold with 4 or 6 fringe setae; ventral tubular ducts scattered over venter; multilocular pores normally with 7 loculi. Other characters: Multiloculars present in vulvar area forward to segment 2, especially submarginally; dorsal tubular ducts present; tibio-tarsus articulated, with sclerosis; claw without denticle; claw digitules equal; 3 pairs of prevulvar setae (posterior pair often obscured by anal plates); stigmatic setae differentiated from other marginal setae, middle seta longer than lateral setae; anal plates with posterior margin about equal in length to anterior margin; antennae 8-segmented; preopercular pores inconspicuous, restricted to area anterior of anal plates.


Pulvinaria hydrangeae is similar to P. floccifera by having multilocular pores predominantly with 7 loculi and some marginal setae frayed or expanded. Pulvinaria hydrangeae differs by having 1 subdiscal seta on each anal plate (absent in P. floccifera), no submarginal tubercles (usually present in P. floccifera), and ventral tubular ducts in submarginal area of head (absent in P. floccifera).

U.S. quarantine notes

This species was intercepted 1 time at a U. S. port-of-entry between 1995 and 2012, originating from Japan.We also have examined specimens taken in quarantine from France (Acer) and Japan (Camellia). ScaleNet includes hosts in 11 plant families from the Australasian, Nearctic and Palaearctic zoogeographic regions. A few other species of Pulvinaria have been taken in quarantine in addition to P. floccifera (Westwood), P. hydrangeae, P. ixorae Green, P. polygonata Cockerell, P. psidii Maskell and P. urbicola Cockerell including: P. aurantii Cockerell (Japan, on Citrus); P. citricola Kuwana (Ecuador, on Musa; Japan, on Diospyros); P. elongata Newstead (Colombia, on Oryza ); P. horii (Kuwana) (Japan, on Acer); P. neocellulosa Takahashi (India, on Murraya); and Pulvinaria vitis (Canada, on Tilia).

Important references

Canard1969; Gill1988; HamonWi1984; HodgsoHe2000; Steinw1946.

Scalenet catalog and citation list

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