Aulacaspis yasumatsui

Aulacaspis yasumatsui Takagi
 

Damage in Guam	Cycad mortality	More Guam damage	Severe infestation
Severe infestation II

Cycad aulacaspis scale (sago palm scale, asian cycad scale)
The cycad aulacaspis scale was first detected on Guam in late 2003 on cycads planted near hotels. The scale is native to Thailand and southern China. During the 1990s, it was introduced accidentally to Florida and Hawai`i on imported cycads. It was probably introduced to Guam in the same way (Moore et al., 2005)

The cycad scale has become a major pest of both native cycads (Cycas micronesica) and horticultural cycads throughout Guam. Badly infested cycads are killed if they are not treated (Moore et al., 2005). Cycas micronesica is endemic to Micronesia and is the dominant forest tree on Guam. Unfortunately, C. micronesica seems particularly susceptible to the scale insect, with 100% mortality in infested areas. The cycad scale is spreading rapidly on Guam and threatens the entire population of 1.5 million trees (Brooke, pers. comm., 2005).

Since nurseries on Guam ship plants to other Micronesian islands where C. micronesica is present, the scale might soon threaten cycads throughout Micronesia (Brooke, pers. comm., 2005).

A lady beetle (Rhyzobius lophanthae) introduced to Hawai`i in the 19th Century as a biological control agent for another scale pest, has provided some control of the cycad scale there. Rhyzobius lophanthae is being introduced on Guam, although it is not certain whether the beetle will decrease the scale population enough to prevent cycad mortality. Entomologists at the University of Guam are searching for other possible biological control agents (Moore et al., 2005).

Sources
Brooke, Anne. Personal communication, 2005. Wildlife Biologist, U.S. Fish and Wildlife Service, Guam National Wildlife Refuge.

Moore, A., I. Iriarta, and R. Quitugua. 2005. Asian cycad scale Aulacaspis yasumatsui Takagi (Homoptera: Diaspididae). Cooperative Extension Service, Agriculture and Natural Resource Division, University of Guam, Pest Sheet 2005-01.