Introduction and Distribution:
Japanese wax scale, also known as tortoise wax scale, is native to Eastern Asia and is currently a pest of significant economic impact for citrus and other fruit crops in Asia and Europe. Specific countries of record include: Japan, China, Korea, France, Italy, Slovenia, United Kingdom and Croatia. It has also been reported in Russia. Japanese wax scale has not yet been found in the U.S., but it is considered a serious threat and is included in the 2009 pests of national concern for USDA-APHIS-PPQ.
Japanese wax scale has a wide host range. It has been reported feeding on over 100 plant species within 27 families, many of these species are grown in the U.S. In the U.S. the potential hosts of greatest concern for potential economic damages include: apples, citrus, peaches, pears, soft hardwood and hardwood trees. Other potential hosts include: Camellia sinensis (tea), Citrus, Citrus deliciosa (Mediterranean mandarin), Citrus reticulata (mandarin), Diospyros kaki (oriental persimmon), Hedera helix (ivy), Ilex aquifolium (Christmas holly), Jasminum (jasmine), Laurus nobilis (bay laurel), Poncirus trifoliate (trifoliate orange), Prunus (stone fruit), and Ziziphus jujuba (common jujube).
Potential Economic Impact and Description of Damage:
In general, Japanese wax scale adapts well to climates ranging from seasonally cool and moist to warm and dry. It is anticipated that at least 68% of the continental U.S. would have a suitable climate for establishment. All life stages feed on leaves, stems and fruits. In addition to the direct feeding damage, the honeydew secreted during feeding results in sooty mold growth. Common symptoms include reduction of vigor, chlorosis of leaves, discoloration of fruit, wilting, foliage and/or stem dieback, and premature foliage, flower and fruit drop. Under extremely high populations, feeding may cause death of the host. Sooty mold may also reduce quality, yield and marketability of the fruit or ornamental by reducing photosynthesis.
Japanese wax scale will resemble Florida wax scale (Ceroplastes floridenis) in the field. The body is oval or rectangular. When viewed from the side, older females look convex and young females appear flat. The body is reddish brown and has a thick oily wax covering. The wax covering is somewhat pinkish-white to pinkish-grey. Adult females are approximately 4mm in length and 3.5 mm in width. An ovisac for egg laying is not present.
Reporting Suspect Samples:
Japanese wax scale is a pest of concern not known to occur in the U.S. Any suspicious specimens should be submitted to your local diagnostic lab (http://www.npdn.org/), or items of concern should be reported to your local state department of agriculture (SDA) If you are not familiar with your local SDA, you may go to an interactive state map available at: http://nationalplantboard.org/member/index.html. Note that the USDA-APHIS-PPQ and your local SDA may need to implement a quarantine or eradication program if this pest is detected in low population levels. Proper identification is necessary in order to confirm the presence of Japanese wax scale.
In China and Italy, Japanese wax scale has only one generation per year. These scales have the following developmental stages: egg, nymph (3 nymphal instars or ‘crawlers’) and adult. Japanese wax scale development depends available hosts for feeding and oviposition. Eggs are laid in a chamber under the body of the adult female. Each female typically lays 395 eggs, but is capable of laying up to 2500 eggs. The crawler stage is the only stage in which they move and are able to be dispersed by wind. Once they find a suitable feeding site and they stop moving, they settle and start producing wax to cover themselves. In Italy, mated females overwinter, and oviposition occurs in May and June. Eggs hatch in June, and then pass through all the nymphal stages. Adult females are evident in September, and then prepare for the overwintering stage.
As this pest is not established in the continental U.S., references to management programs are not available. The main source of dispersal is movement of infested plant material, but crawlers can also disperse by wind and by walking short distances. Removal and disposal of plant material that appears to be infested with a problematic scale will help prevent its spread.
Always inspect plant material before introducing the plant to your landscape or garden. All homeowners and Master Gardeners should contact their local cooperative extension service for management related questions pertaining to their local climate. If you're not sure where to find your local cooperative extension office, visit: http://www.csrees.usda.gov/Extension/.
As with most scale insects, chemical control is only possible in the crawler stage before they settle and form a protective wax covering. . In areas where Japanese wax scale has established, the following parasitoids have effectively controlled populations: Anicteus beneficus Ishii, A. ohgushii Tach., Coccophagus hawaiiensis Timb., C. yoshidae Nak. (Hymenoptera, Aphelinidae), Microterys clauseni (Hymenoptera, Encyrtidae), M. ericeri Ishii, Tetrastichus muracamii (Hymenoptera, Chalcidoidea). Some Coccinellids, such as Rhyzobius forestieri, have also shown to be good potential predators for classical biological control.
- CAPS. 2005. Citrus Commodity Survey Reference. Found at: http://www.aphis.usda.gov/plant_health/plant_pest_info/pest_detection/commodity_ref.shtml
- Davis, E.E., S. French, and R.C. Venette. 2005. Mini Risk Assessment Japanese Wax Scale: Ceroplastes japonicus Green [Hemiptera:Coccidae] Found at: http://www.aphis.usda.gov/plant_health/plant_pest_info/pest_detection/downloads/pra/cjaponicuspra.pdf.
- European and Mediterranean Plant Protection Organization. Data Sheet on Forest Pests Ceroplastes japonicus. Found at: http://www.eppo.org/QUARANTINE/Pest_Risk_Analysis/PRAdocs_insects/draft_ds/DS%20CERPJA%2003-10062.doc
- Masten-Milek, T., G. Seljak, and M. Simala. 2007. ceroplastes japonicus (Green) (Hemiptera:Coccidae) A New Pest in Croatia and its Distribution. Found at: http://www.dvrs.bf.uni-lj.si/spvr/2007/57masten_07.pdf
- USDA- ARS & APHIS. Scale Insects: Identification Tools for Species of Quarantine Significance. Last Update: 02-09 Found at: http://www.sel.barc.usda.gov/scalenet/scalenet.htm
- USDA-APHIS. Pests of National Concern for FiscalYear 2009. Found at: http://www.aphis.usda.gov/plant_health/plant_pest_info/pest_detection/downloads/survey/Appendix-G.pdf
- USDA-APHIS. Analytic Hierarchy Process Prioritized Pest List For FY 2009. Found at: http://www.aphis.usda.gov/plant_health/plant_pest_info/pest_detection/downloads/survey/Appendix-D.pdf