Spilococcus mamillariae (Bouche)

Family

Pseudococcidae

Common name

Cactus mealybug

Field characters

Body oval, yellow or green and also gray; body covered by layer of white mealy wax, allowing body segmentation to be visible; ovisac covers body; occurring on arboreal parts of plant; ovisacs often on spines or at base of spines.

Validation characters

Cerarii numbering 9 to 15 pairs, some on head and thorax, anterior pairs poorly developed; translucent pores present on hind coxa and tibia, those on tibia usually in tight group; claw with small denticle; oral-rim tubular ducts scattered over dorsum, present laterally on head, thorax, and abdomen of venter; oral-collar tubular ducts restricted to abdomen and posterior thorax; circulus present; anal bar absent.

Comparison

Spilococcus mamillariae is similar to S. eriogoni (Ehrhorn) by having fewer than 17 pairs of cerarii, denticle on claw, many oral-rim tubular ducts, 16-18 pairs of cerarii, and oral-collar tubular ducts restricted to abdomen and posterior thorax. Spilococcus mamillariae can be distinguished (characters of P. eriogoni are in parentheses) by having circulus present (usually absent), oral-rim tubular ducts absent from ventromedial areas of thorax (present), multilocular pores on segment III (absent).

U.S. quarantine notes

This species was intercepted at U. S. ports-of-entry 10 times between 1995 and 2012, with specimens originating from France, Germany, Italy, Mexico, The Netherlands, and The United Kingdom of Great Britain and N. Ireland. We also have examined specimens taken in quarantine from Canada (Mammillaria); Chile (unknown host); Germany (cactus, Cereus, Echinocactus); Japan (Cactaceae); Mexico (Aporocactus, Corypantha, Echinocactus, Ferrocactus, Mammillaria, Sedum, Stenocactus, Strombocactus, Wilcoxia); The Netherlands (cactus); South Africa (possibly Avonia ustulata); Spain (cactus); Switzerland (cactus); The United Kingdom of Great Britain and N. Ireland (England)(Lobivia); Uruguay (Echinocactus). ScaleNet lists hosts in Aizoaceae, Epacridaceae, Euphorbiaceae, Malpighiaceae, and the majority of host species in Cactaceae. It is also most commonly intercepted on cactus. ScaleNet distribution records for S. mamillariae include several countries in the Australasian, Nearctic, Neotropical and the Palaearctic zoogeographic regions. One other species of Spilococcus, S. geraniae Rau (Mexico, on Crataegus) has been taken at U. S. ports-of-entry.

Important references

Ferris1950b; McKenz1967; WilliaGr1992

Scalenet catalog and citation list

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