Biocontrol News and Information 34(1), 1N–8N www.cabi.org/BNI General News Status and Biological Control of Cycad datory insecticide treatment as a condition of entry Aulacaspis Scale for host plants coming from infected countries; or (iii) close inspection of host plants for scale infestations According to the IUCN/SSC* Cycad Specialist with subsequent insecticide treatment if infestations Group’s action plan (http://data.iucn.org/dbtw-wpd/ are found (www.cycadsg.org/publications/CAS/ edocs/2003-010.pdf), cycads are the most ancient Cycad-Aulacaspis-Scale-Pest-Alert.pdf). However, seed plants still living today and the extant c. 297 the minute size of the first-instar crawlers allows taxa form one of the world’s most threatened groups. them to reach plant tissues not accessible to The invasive cycad aulacaspis scale, Aulacaspis yas- inspection2. The unique morphology of C. revoluta umatsui (CAS), is a threat to native cycad stems and cataphylls (thickened leaves that protect populations worldwide as well as a costly pest for the apical meristem), together with hidden root sur- horticultural industries. The diaspidid or armoured faces, mean that even the most thorough quarantine scale, CAS, is already documented as threatening inspection will not find all the scales. The efficacy of the extinction of the endemic cycads Cycas microne- insecticide treatments cannot be guaranteed for the sica in Guam and C. taitungensis in Taiwan same reason. Thus the best hope for prevention is (www.cycadsg.org/pages/CAS.htm). A few species – prohibition of entry from infested areas. However, notably C. revoluta – are important ornamentals glo- even where this is implemented – as in Palau - there bally and trade in whole plants has been the is no guarantee that CAS will be kept out indefi- pathway for CAS spread between countries, nitely. Strict quarantine is also essential: CAS although local spread can occur via wind dispersal of infestation progresses rapidly and scale covers are first-instars also. This article outlines the limitations easily detected on leaves within a few weeks of of all but the most stringent import restrictions, and crawlers settling. Imported cycads truly need to be then looks at the current status of CAS and its con- quarantined, rather than just inspected and trol in some invaded countries, focusing on biological released. If CAS evades quarantine, by the time this control and its prospects. becomes apparent in the field and its identity is con- firmed the insect may have been established for a CAS attacks primarily Cycas species and is native to year or more, by which time all hope of eradication is an area of South-east Asia between Thailand and long past. peninsular Malaysia in the west and Vietnam in the east. It has spread within Asia, becoming a pest in Continental USA southern China in the 1990s through the importa- tion of infested C. inermis from Vietnam; later In Florida, the thriving, multi-million-dollar cycad spreading to Hong Kong in 1992, where it caused sig- nursery industry combines mechanical, cultural, nificant damage to cycads; to Taiwan in the early chemical and biological control methods to mitigate 2000s; and to Singapore, Malaysia and Indonesia1. CAS damage. Natural enemies already present, including the predatory beetle Cybocephalus nippon- Outside Asia, CAS was first identified in south icus and the coccinellid Rhyzobius lophanthae Florida in 1996 following accidental introduction on (introduced previously from Australia to control cycads legally imported for botanical gardens. By the diaspidid pests) did not provide adequate control. time it was identified it had infested 22 cycad spe- cies. It has since spread north to South Carolina and From surveys in Thailand, Richard Baranowski west as far as Texas. Cycads of Florida origin have (University of Florida), with Banpot Napompeth probably been responsible for the scale’s spread to (National Biological Control Research Center, Thai- some Caribbean islands and Costa Rica, and to land), identified and released in Florida two natural Hawaii (first reported in 1998), Guam (2003), Rota in enemies of CAS: Cy. nipponicus and an aphelinid the North Marianas (2007) and Palau (2008) in the parasitoid, Coccobius fulvus. Pacific. It has also been reported from a few Euro- pean countries (France, Croatia and Bulgaria)1. In Ronald Cave (University of Florida) and Ru Nguyen its introduced range, CAS is highly destructive. (Florida Department of Agriculture) found Co. fulvus Long-term infestations lead to sequential defolia- in northern Vietnam. This was released (after cli- tions, with leaves of each successive flush being mate matching) in northern Florida in 2007, and smaller and fewer, ultimately leading to plant death, established and spread. From 2003 to 2011, Co. even of mature cycads and sometimes within only a fulvus was the only parasitoid observed in CAS in few months of becoming infested. Florida; although high rates of parasitism by it have been seen recently in northern Florida, it seems The IUCN/SSC Cycad Specialist Group proposes unable to provide satisfactory control. The impact of preventing introduction as the most effective way of both Cy. nipponicus and Co. fulvus may be affected combating this pest. Its three alternatives for pre- by hyperparasitism although the extent is unknown: venting entry centre on quarantine measures: (i) Co. fulvus is hyperparasitized by Ablerus sp. and Cy. prohibiting entry of host cycad plants from countries nipponicus is attacked by the prepupal-pupal parasi- known or suspected of having infestations; (ii) man- toid Aphanogmus albicoxalis. Are we on your mailing list? Biocontrol News and Information is always pleased to receive news of research, conferences, new products or patents, changes in personnel, collaborative agreements or any other information of interest to other readers. If your organization sends out press releases or newsletters, please let us have a copy. In addition, the editors welcome proposals for review topics. 2N Biocontrol News and Information 34(1) An encyrtid parasitoid commonly found by Cave and native Cycas micronesica, a dominant component of Nguyen in China, Vietnam and Thailand in 2006, Guam’s limestone and ravine forests, which it has 2007 and 2009 surveys was Arrhenophagus chionas- also devastated. Without treatment, the mortality pidis. This wasp had been reported attacking rate for the native cycads is 100% within one year of another diaspidid, white peach scale (Pseu- infestation. After six years of CAS attack no recruit- daulacaspis pentagona), in Florida many years ment is occurring among the survivors, even after before but had not at that time been recorded from the introduction of a biocontrol agent. Rhizobius CAS there. It was found in CAS in Florida in 2012 lophanthae was introduced from Hawaii in 2005 and but although rates of parasitism were in some cases is protecting mature plants, but seedlings are still very high, it has no apparent control impact on CAS severely impacted. Research has uncovered a populations. number of factors contributing to control breakdown: there is a disparity in size between pest and predator During the survey in Thailand in 2007, an unde- which means that CAS occupying tiny spaces escape scribed coccinellid (subsequently named predation2. In addition, CAS feeding on C. revoluta Phaenochilus kashaya) was discovered at two locali- are protected from predation by the plant’s ties where scale infestations were light. This species trichomes7. Possibly seedlings and young cycads are is under investigation in Florida. No-choice testing particularly susceptible to mortality from CAS infes- indicated it would feed on early instars of some other tation because R. lophanthae predation rate is groups, including aphids and mealybugs, and small reduced near the ground8. Although many mature larvae of Cy. nipponicus, R. lophanthae, and CAS trees died in the interval between arrival of the scale mummified by Co. fulvus, but choice tests suggest it and establishment of the beetle, R. lophanthae has is normally a specialist on armoured scales including been responsible for the survival of mature trees; but CAS. Mixed colonies of P. kashaya and Cy. nippon- no seedlings are surviving9. icus perform well in the laboratory. It is notable that Cy. nipponicus, Co. fulvus and P. kashaya are all Long-term prospects are not good. A study moni- found in Thailand, but during exploration only A. toring C. micronesica, which was initially a healthy, chionaspidis, Cy. nipponicus, and P. kashaya were stable population, concluded that Guam has already seen on plants at the same locality. Another factor lost over 90% of its C. micronesica to CAS, and the makes P. kashaya an exciting discovery: preliminary trend line predicts extinction in the wild by 201910. results suggest that the reproductive rate of CAS This is a first-class ecological disaster that few people outstrips the consumption rate of Cy. nipponicus, Co. know about, and one that was predicted as far back fulvus and R. lophanthae; but P. kashaya consumes as 200011 but unfortunately discounted at the time. CAS faster than the scale reproduces (which does In a 2002 forest survey of Guam, C. micronesica was create problems for quarantine testing, as the pred- listed as the most numerous plant with a stem diam- ator wipes out the scale colony). eter greater than five inches [12.5 cm]. By 2006, the plant was on the IUCN Red List. Among other natural enemies tested, the fungus Isaria fumosorosea performed well in the 3 Small numbers of a second biocontrol agent, Cocco- laboratory , as did entomopathogenic nematodes, bius fulvus, were imported to Guam from Florida and but similar results could not be obtained in the field released in 2005 but the parasitoid did not establish. and funding is not currently available to pursue this Current efforts are focused on trying to import A. work. lingnanensis from Hawaii, selected because it coex- ists with R.