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Marler and Lawrence (2012) predict extirpation of wild cycads on Guam by 2019 if current trends persist. CAS, described by Takagi (1977), is considered a minor pest of Cycas within its native Asian range (Anonymous 20...
This cycad-specific scale pest invaded Guam in 2003 and, in only a few years, this pest caused over 90% mortality to maturing trees and 100% mortality to seedlings.
In a 15-year study, published in the May 2020 issue of Diversity journal, researchers studied the rate and influences of mortality in Guam cycads affected by invasive species.
A Cycas micronesica tree in Guam, right, shows the extent of damage done by invasive insect herbivores, a scale called Aulacaspis yasumatsui, as compared to a healthy Cycas micronesica tree, left, found in Yap.
The Guam National Wildlife Refuge (Refuge) is home to several thousand federally threatened fadang (Cycas micronesica). The fadang is listed due to the impact of the cycad aulacaspis scale (scale), an invasive insect.
The armored scale known as cycad aulacaspis scale invaded Guam in 2003 and began killing individuals of the host tree Cycas micronesica by 2005. The plant mortality dynamics of this case study have been reported in detail.
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).
ACS now infests non-native and indigenous cycads throughout Guam; severe infestations result in cycad mortality within a few months. To date, over 25% of the native cycads have died.
PDF | On Apr 19, 2017, Benjamin Deloso published Status of Cycad Aulacaspis Scale on Guam | Find, read and cite all the research you need on ResearchGate
Species Cycad aulacaspis scale / Aulacaspis yasumatsui. Also known as Asian cycad scale.
