California Pest Rating for
Hemiberlesia palmae (Cockerell): Tropical palm scale
Pest Rating: A
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History & Status:
Background: Hemiberlesia palmae is a widely-distributed armored scale. This highly polyphagous species has been reported to feed on plants in at least 92 genera in 53 families. Reported hosts include avocado, banana, bromeliads, cactus, citrus, coffee, mango, olive, palms (including coconut), and at least one species of fern (Agricultural Research Service, 1969; García Morales et al., 2016; Kondo and Muñoz, 2016; McKenzie, 1956; Santos and Wolff, 2015; Sepúlveda et al., 2010; Thuy et al., 2011). Although it is a widespread species and feeds on many economically-important plants, no information was found suggesting that it is a significant pest (Dekle, 1976; Granara De Willink and Claps, 2003; Nuñez, 2008). Feeding is reported to cause yellow spots on leaves (Schmutterer, 1971). Hemiberlesia palmae is reported to be parthenogenetic (Brown, 1965).
Worldwide Distribution: Hemiberlesia palmae is apparently of neotropical origin, but it has been established over a wide area. It has been reported from Europe (including Spain, Portugal, and in greenhouses in the United Kingdom), Africa (including Angola, Cameroon, Ghana, Kenya, South Africa, Tanzania, and Zaire), Asia (including China, India, Indonesia, Philippines, Thailand, and Vietnam), Australia, the Caribbean (including Antigua and Barbuda, Cuba, and Jamaica), Central America (including Guatemala and Panama), New Guinea, numerous Pacific islands, South America (including Argentina, Bolivia, Brazil, Chile, Colombia, Ecuador, and Peru), and North America (Mexico and the United States, where it is reported from Alabama, Florida, and Puerto Rico) (Amún and Claps, 2015; Ben-Dov and Sánchez-García, 2015; Culik et al., 2011; De Lotto, 1967; Franco et al., 2011; García Morales et al., 2016; Germain et al., 2008; González and Charlín, 1968; Granara De Willink and Claps, 2003; Kondo and Muñoz, 2016; Malumphy, 2012; Malumphy, 2014; Miller, 2005; Ponsonby, 1994; Szent-Ivany and Catley, 1960; Thuy et al., 2011; Vasquez et al., 2002; Waltman et al., 2016; Williams, 1973). Some (possibly most) of the records from more temperate areas (e.g., Europe) were associated with greenhouses.
Official Control: Hemiberlesia palmae is regulated in New Zealand and is a controlled pest in Korea (Food and Agriculture Organization, 2016).
California Distribution: Although Hemiberlesia palmae has been found at various times in nurseries in California, it is not currently known to be established in the state.
California Interceptions: Hemiberlesia palmae has been intercepted numerous times on plant material from various origins, including Florida, Central America, and South America (California Department of Food and Agriculture).
The risk Hemiberlesia palmae would pose to California is evaluated below.
Consequences of Introduction:
1) Climate/Host Interaction: Hemiberlesia palmae is highly polyphagous and availability of host plants is not likely to limit its potential distribution in California. The known distribution of this species includes many tropical and subtropical areas, but some records are from desert areas as well, for example, the Azapa Valley in Chile (González and Charlín, 1968). It seems likely that climate would limit the potential distribution of this scale to the warmer southern portions of the state. Therefore, Hemiberlesia palmae receives a Medium (2) in this category.
– Low (1) Not likely to establish in California; or likely to establish in very limited areas.
– Medium (2) may be able to establish in a larger but limited part of California.
– High (3) likely to establish a widespread distribution in California.
2) Known Pest Host Range: Hemiberlesia palmae is highly polyphagous and has been reported to feed on plants in at least 53 families. Therefore, it receives a High (3) in this category.
– Low (1) has a very limited host range.
– Medium (2) has a moderate host range.
– High (3) has a wide host range.
3) Pest Reproductive and Dispersal Potential: Hemiberlesia palmae apparently has high reproductive and dispersal potential. It is parthenogenetic, so a female does not have to mate to produce viable offspring. The frequent interceptions on plant material indicate that it could be spread through that pathway. Therefore, it receives a High (3) in this category.
– Low (1) does not have high reproductive or dispersal potential.
– Medium (2) has either high reproductive or dispersal potential.
– High (3) has both high reproduction and dispersal potential.
Economic Impact: Hemiberlesia palmae is regulated by some countries, and if it became established in California, this could lead to the loss of markets. If control measures were taken by growers to control this scale, it would likely increase production costs. Therefore, it receives a Medium (2) in this category.
Economic Impact: B, C
A. The pest could lower crop yield.
B. The pest could lower crop value (includes increasing crop production costs).
C. The pest could trigger the loss of markets (includes quarantines).
D. The pest could negatively change normal cultural practices.
E. The pest can vector, or is vectored, by another pestiferous organism.
F. The organism is injurious or poisonous to agriculturally important animals.
G. The organism can interfere with the delivery or supply of water for agricultural uses.
Economic Impact Score: 2
– Low (1) causes 0 or 1 of these impacts.
– Medium (2) causes 2 of these impacts.
– High (3) causes 3 or more of these impacts.
5) Environmental Impact: If Hemiberlesia palmae became established in California, it would likely attack a wide variety of crop and ornamental plants, and this could trigger treatments. Therefore, it receives a Medium (2) in this category.
Evaluate the environmental impact of the pest on California using the criteria below.
Environmental Impact: D
A. The pest could have a significant environmental impact such as lowering biodiversity, disrupting natural communities, or changing ecosystem processes.
B. The pest could directly affect threatened or endangered species.
C. The pest could impact threatened or endangered species by disrupting critical habitats.
D. The pest could trigger additional official or private treatment programs.
E. The pest significantly impacts cultural practices, home/urban gardening or ornamental plantings.
Environmental Impact Score: 2
– Low (1) causes none of the above to occur.
– Medium (2) causes one of the above to occur.
– High (3) causes two or more of the above to occur.
Consequences of Introduction to California for Hemiberlesia palmae: Medium (12)
Add up the total score and include it here.
–Low = 5-8 points
–Medium = 9-12 points
–High = 13-15 points
6) Post Entry Distribution and Survey Information: Although Hemiberlesia palmae has been found in various nurseries in California, it has apparently been eradicated whenever found and is not considered to be established in the state. It receives a Not established (0) in this category.
–Not established (0) Pest never detected in California, or known only from incursions.
–Low (-1) Pest has a localized distribution in California, or is established in one suitable climate/host area (region).
–Medium (-2) Pest is widespread in California but not fully established in the endangered area, or pest established in two contiguous suitable climate/host areas.
–High (-3) Pest has fully established in the endangered area, or pest is reported in more than two contiguous or non-contiguous suitable climate/host areas.
7) The final score is the consequences of introduction score minus the post entry distribution and survey information score: Medium (12)
There is significant uncertainty regarding the ability of this scale to inflict significant damage on plants in California. Although this scale is widespread and feeds on a wide diversity of plants, including many economically important ones, no information was found quantifying damage caused by this feeding.
Conclusion and Rating Justification:
Hemiberlesia palmae is a highly polyphagous scale that could become a pest in California if it became established here. In addition, it is regulated by some countries and its presence in the state could impact trade. It is not known to be present in California. For these reasons, an “A” rating is justified.
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Amún, C. and Claps, L. E. 2015. Listado actualizado de diaspídidos sobre frutos tropicales y primer registro de Pseudaulacaspis cockerelli (Cooley) (Hemiptera: Diaspididae) para la Argentina. Insecta Mundi 0449:1-11.
Ben-Dov, Y. and Sánchez-García, I. 2015. New data on several species of scale insect (Hemiptera: Coccoidea) from southern Spain. Boletín de la Sociedad Entomológica Aragonesa 56:313-317.
Brown, S.W. 1965. Chromosomal survey of the armored and palm scale insects (Coccoidea: Diaspididae and Phoenicoccidae). Hilgardia 36:189-294.
California Department of Food and Agriculture. Pest and damage record database. Accessed July 3, 2018:
Culik, M. P., Wolff, V. R. S., Peronti, A. L. B. G., Ben-Dov, Y., and Ventura, J. A. 2011. Hemiptera, Coccoidea: Distribution extension and new records for the states of Espírito Santo, Ceará, and Pernambuco, Brazil. Check List 7:567-570.
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De Lotto, G. 1967. A contribution to the knowledge of the African Coccoidea (Homoptera). Journal of the Entomological Society of South Africa 29:109-120.
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Granara De Willink, M. C. and Claps, L. E. 2003. Cochinillas (Hemiptera: Coccoidea) presents en plantas ornamentals de la Argentina. Neotropical Entomology 32:625-637.
Kondo, T. and Muñoz, J. A. 2016. Scale insects (Hemiptera: Coccoidea) associated with avocado crop, Persea americana Mill. (Lauraceae) in Valle del Cauca and neighboring departments of Colombia. Insecta Mundi 0465:1-24.
Malumphy, C. 2012. Arthropods intercepted on air plants (Tillandsia spp.) imported from Guatemala into England and Wales. Entomologist’s Gazette 63:54-62.
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Santos, M. G. and dos Santos Wolff, V. R. 2015. Two species of armored scale insects (Hemiptera: Diaspididae) associated with sori of ferns. EntomoBrasilis 8:232-234.
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Kyle Beucke, 1220 N Street, Room 221, Sacramento, CA, 95814, 916-403-6741, plant.health[@]cdfa.ca.gov
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Pest Rating: A
Posted by ls