Biological control agents of the cycad aulacaspis scale, Aulacaspis yasumatsui

Biological control is a key element in any management program to control the cycad aulacaspis scale, Aulacaspis yasumatsui Takagi. An overview of the natural enemies known to attack the scale is presented. Sixteen species of predatory lady beetles (Coccinellidae) have been collected on scale-infested cycads in south Florida. Chilocorus cacti (L.), Cryptolaemus montrouzieri Mulsant and Exochomus childreni childreni Mulsant are frequently encountered, but do not suppress scale populations. Rhyzobius lophanthae (Blaisdell) is a voracious predator that reportedly provides good control of cycad aulacaspis scale in Hawaii, but has a sparse distribution on cycads in Florida. The minute predatory beetle Cybocephalus nipponicus Endrody-Younga is abundant and widespread throughout the eastern USA and contributes to limited scale mortality. The parasitic wasp Coccobius fulvus (Compere and Annecke) was introduced from Thailand into Florida in 1998, but has not been effective in controlling the pest. Overall parasitism in south Florida varies from 10 to 40%. Arrhenophagus chionaspidis Aurivillius and Aprostocetus purpureus (Cameron) parasitize cycad aulacaspis scale throughout Southeast Asia and are currently under study as potential biological control agents in Florida. Four commercially available entomopathogenic nematodes were tested in the laboratory and all were observed infecting and killing female scales. No pathogens are known to cause disease in the cycad aulacaspis scale.