New Pest Found Only on The Big Island – Ice Plant Scale Insect (Pulvinariella mesembryanthemi)

NEW PEST ALERT! Please keep a look out for the ice plant scale insect (Pulvinariella mesembryanthemi) that can attack not only non-native plants such as the ice plant (Carpobrotus species) but could also attack native ‘akulikuli (Sesuvium species), ‘ihi (Portulaca species) and species in the plant family Chenopodiaceae (such as the native ‘aheahea).

Pulvinariella mesembryanthemi

It is currently only known from the Kona side of the Big Island, but pests can hitchhike to other islands. If you see this scale, report it to the Hawaii Department of Agriculture at 643-PEST or 832-0566 (O’ahu).

Common name: Iceplant scale

Field Characters: Body oval to circular; moderately convex in cross section; body green in newly formed females turning reddish brown in older females; without obvious wax covering except just before oviposition when covered with sparse mealy secretion; ovisac produced beneath and behind female, convex, often with mediodorsal goove, white, flocculent, about 1 or 2 times length of body. Occurring on succulent leaves of host. Males are common. Eggs laid inside ovisac.

Validation characters – Diagnosis: Marginal setae spinelike, usually curved, with simple apices; without submarginal tubercles; anal plates each with 1 subdiscal seta. Other characters: Each anal plate with 3 apical setae and 2 or 3 subapical setae; anal fold with 4 fringe setae; ventral tubular ducts scattered over surface; multilocular pores normally with 10 loculi; multiloculars present in vulvar area forward to segment 2; dorsal tubular ducts present; tibio-tarsus articulated, with sclerosis; claw with minute 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 relatively conspicuous, restricted to area anterior of anal plates.

Comparison: Pulvinariella mesembryanthemi is similar to P. delottoi by having spinelike marginal setae, numerous tubular ducts, and multilocular pores predominantly with 10 loculi present in medial areas of most abdominal segments. Pulvinariella mesembryanthemi differs by having thin and predominantly curved marginal setae (marginal setae in P. delottoi are relatively thick and straight).

U.S. quarantine notes: Between 1995 and 2005, this species was intercepted at U. S. ports-of-entry 1 time (Italy on Aizoaceae). We have examined specimens taken in quarantine from Italy (Mesembryanthemum, Portulaca), Mexico (Aizoaceae), and Portugal (Mesembryanthemum). ScaleNet includes hosts in only 2 plant families and species in Carpobrotus (=Mesembryanthemum) are the most common. The species is reported from all zoogeographic regions except the Oriental region. No other species of Pulvinariella has been taken in quarantine.

References: Gill1988; Hodgso1994a; WashbuFr1985.

All references mentioning: Pulvinariella mesembryanthemi

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