RegionalRegional PestPest AlertAlert

Cycad Aulacaspis Scale Aulacaspis yasumatsui Takagi

Origin and Distribution of shaped (occasion- Aulacaspis Scale ally). The female body, occasionally The cycad aulacaspis scale (CAS), native to Thailand, was first visible through the reported in Miami, Florida in 1996. Despite extensive regulatory armor, is orange. efforts, CAS has subsequently spread to 43 of 67 counties and is The male armor is considered established within Florida. CAS also was reported from white, 0.5–0.6 mm Hawaii in 1998. Interceptions of CAS also occurred in Texas in 2002 in length and tricar- and 2004 and in Georgia in 2004. Unconfirmed reports also indicate inate (elongate with that CAS has subsequently established in Texas (Rio Grande Valley). three parallel ridg- Other known distributions of CAS include China, Singapore, Hong es). On the surface, Kong, Cayman Islands, Puerto Rico, and the Vieques Islands, and the CAS resembles the U.S. Virgin Islands. In 2004, CAS was detected in the Guam the magnolia white landscape, and the identity of CAS was confirmed in 2005. The scale, Pseudau- introduction of this scale into Guam is not only impacting their lacaspis cockerelli. ornamental landscape cycad species but also is threatening native However, the female cycad species. body of the mag- Dense population of CAS nolia white scale is Host yellow and more elongate than the body of CAS. Male scales, although smaller than CAS has been observed on from three families (Cycada- female scales, typically outnumber the females on infested plants. ceae, , and Stangeriaceae) in Florida, but it is the species that seems most preferred. Two commonly grown cycads, Life Cycle queen and king sagos (Cycas circinalis and Cycas revoluta), are very susceptible to attack. In Guam, infestation of the endemic Cycas Female scales normally produce 100 eggs or more during their life- micronesica also is a concern. time. Eggs are deposited underneath the scale armor and hatch in approximately 8–12 days. Male and female scales develop from eggs Description of CAS into first instars (crawlers). Newly emerged first instars disperse by “crawling” and locate an appropriate feeding site. Dispersal typically Scales feed by inserting their stylet-like mouthparts into the occurs by crawling; however, first instars also may be dispersed tissue. Like other armored scales, CAS produces domicile-like waxy by wind. Once crawlers have “settled,” they start feeding, molt to covering (armor) that is not attached to the female body. The female the second instar, and continue to feed at the same site for the armor is white, remainder of their life. The scale sometimes settles on subter- 1.2–1.6 mm in ranean areas of the host, subsequently resulting in problems length, and may be in using natural enemies for biological control. Female pear-shaped (usu- scales molt into the third and final instar (adult ally) or irregularly stage). The second, third, and adult stage of fe- males are legless. Male scales molt into the prepupal, pupal, and adult stage within Male (narrow) and a few days. Adult males have legs, female (broad) CAS a single pair of obvious and at the bases of leaves, where they are cations (10 days to 3 weeks apart). Oils are not apparent. generally safer to use and less detrimental to native and introduced natural enemies. Infested cycad plants in unmanaged Check for the presence of natural enemies landscapes act as pest reservoirs and are and scales bearing parasitoid emergence sources for infestation of “healthy” plants holes before deciding which product to use. in managed landscapes. Check new plants Applications may not be necessary during before purchase to make sure they are not the winter and should be stopped when already infested with this scale. Monitor active scales are not present. An appar- plants frequently for the presence of the ently clean plant may still harbor scales scale or the initial symptoms, particularly in on its roots. Removal of heavily infested areas where this pest has been seen attack- leaves may reduce population density but ing sago and other Cycas palm species. Look should not be done frequently because it for “white specs” (scale armor) in the crown may reduce plant vigor. Careful disposal of and at the base of leaves. removed leaves is necessary to avoid spread- ing scales to other plants. Maintenance of Control Recommendations clean, healthy plants probably will require a Two natural enemies of CAS were in- continuous investment of time and effort if troduced into Florida in 1997–1998 by CAS is problematic in the area. University of Florida researchers: a preda- ceous beetle, Cybocephalus binotatus, and a parasitic wasp, Coccobius fulvus. Both have For more information on cycad scale, become established in southern Florida visit our Web site at and contribute to the control of the scale. ncipmc.org/action/alerts/cycadscale.php However, because of the explosive nature of this pest species, the natural enemies cannot provide acceptable control levels so far. For information about the Pest Alert program, please contact Laura Iles, co-director of the Cycad infested with CAS Generally, management of CAS will require North Central IPM Center, at [email protected]. the use of oils, other conventional insecti- cides, or a combination. This publication was procuded and distributed wings, and do not feed. Depending on the by USDA-NIFA Integrated Pest Management temperature, females will mature, mate, and Wash infested plants with high-pressure Centers in cooperation with the National Plant Diagnostic Network and APHIS. produce another generation in 21–35 days. water sprays (before any insecticide spray) to dislodge dead and live scales. The second Photo credits: H. Glenn, UF–IFAS and FDACS– and third instars (adult female) cannot DPI Plant Symptoms and move back onto the plant. Apply horticul- Monitoring tural oils and insecticides at recommended Contributing authors: Catharine Mannion, Trop- ical Research and Education Center, University rates. Good coverage is extremely import- Although CAS crawlers initially settle on of Florida, Institute of Food and Agricultural ant to the effectiveness of contact sprays. the trunk and base of the leaves, they also Sciences (UF–IFAS), Greg Hodges, Florida De- Repeated applications may be necessary for may infest the leaf blades, cones, seeds, and partment of Agriculture and Consumer Services, heavy infestations, under certain weather even the roots. Early symptoms include Division of Plant Industry (FDACS–DPI), Aman- conditions, and for some products. No chlorotic spots on the upper side of leaves. da Hodges, Southern Plant Diagnostic Network, single product will kill all the insects on UF–IFAS CAS also can deform and kill new plant your plants or prevent recolonization for growth. Infested leaves become brown and Southern 1862 Land-Grant Universities extended periods. Typically, oils and contact desiccated as populations grow. Very dense Auburn University University of Arkansas insecticides require more frequent appli- populations result in layers of live and dead University of Florida University of Georgia Uni- scales that form a “white crust” on infested versity of Kentucky Louisiana State University plant surfaces. Heavy infestations eventually Mississippi State University North Carolina State lead to plant death. University Oklahoma State University University of Puerto Rico Clemson University University of Pest management of CAS is difficult because Tennessee Texas A&M University Virgina Tech 1) initial infestations typically go unde- University of the Virgin Islands tected or may be confused with those of This work is supported by the Crop Pro- the commonly occurring magnolia white tection and Pest Management Program scale, 2) rapid outbreaks are caused by high (2014-70006-22486) from the USDA population growth rates, and 3) scales feed National Institute of Food and in protected plant structures such as roots Cycad scale with False oleander scale Agriculture. cover flipped off without cover March 2019