Biological control of cycad scale, Aulacaspis yasumatsui, attacking Guam's endemic cycad, Cycas micronesica

Despite attempted classical biological control with a predator and two parasitoids, greater than 90% of Guam's endemic Cycas micronesica plants have been killed since the island was invaded by the cycad aulacaspis scale (CAS), Aulacaspis yasumatsui (Hemiptera: Diaspididae) in 2003. Prior to this invasion, C. micronesica was the most numerous plant in Guam's forests with a stem diameter greater than five inches. The CAS infestation was so severe that by 2006 C. micronesica was listed as endangered by the International Union for Conservation of Nature. This ecological disaster is still unfolding. Marler and Lawrence predict extirpation of wild cycads on Guam by 2019 if current trends persist. The scale predator, Rhyzobius lophanthae, was imported in 2005, established readily and protects mature plants, but seedlings become rapidly infested with scale and none survive. Our immediate objective is to establish a biocontrol agent, in addition to R. lophanthae, which will adequately protect C. micronesica seedlings from CAS-related mortality so that this important endemic plant species can start to recover. We are attempting to import and establish the parasitoid, Aphytis lignanensis.