Chionaspis pinifoliae (pine leaf scale)
- Summary of Invasiveness
- Taxonomic Tree
- Distribution Table
- Risk of Introduction
- Hosts/Species Affected
- Host Plants and Other Plants Affected
- Growth Stages
- List of Symptoms/Signs
- Biology and Ecology
- Natural enemies
- Notes on Natural Enemies
- Means of Movement and Dispersal
- Pathway Vectors
- Plant Trade
- Wood Packaging
- Detection and Inspection
- Similarities to Other Species/Conditions
- Prevention and Control
- Distribution Maps
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IdentityTop of page
Preferred Scientific Name
- Chionaspis pinifoliae (Fitch, 1856)
Preferred Common Name
- pine leaf scale
Other Scientific Names
- Aspidiotus pinifoliae Fitch, 1856
- Leucaspis pinifoliae García Mercet, 1912
- Mytilaspis pinifoliae LeBaron, 1872
- Phenacaspis pinifoliae Ferris, 1937: Sl-93
- Polyaspis pinnaefoliae Lindinger, 1935: 140
- Trichomytilus pinnaefoliae Lindinger, 1933: 166
International Common Names
- English: pine leaf, scale; pine needle scale; pine needle, scale; white pine needle scale
- French: chermes du pin; cochenille des aiguilles du pin
Local Common Names
- : white pine scale
- Cuba: guagua de las hojas del pino
- PHECPI (Phenacaspis pinifoliae)
Summary of InvasivenessTop of page As this species can be a pest on conifers within its native range, it is likely to be invasive and problematic in countries where it is accidentally introduced in the absence of its usual natural enemies.
Taxonomic TreeTop of page
- Domain: Eukaryota
- Kingdom: Metazoa
- Phylum: Arthropoda
- Subphylum: Uniramia
- Class: Insecta
- Order: Hemiptera
- Suborder: Sternorrhyncha
- Unknown: Coccoidea
- Family: Diaspididae
- Genus: Chionaspis
- Species: Chionaspis pinifoliae
DescriptionTop of page When intact and alive, the first instar (crawler) is less than 0.5 mm long, yellow to orange and mobile. The intermediate immature female is sessile, similar to the adult female but smaller, and has only one cast skin incorporated in the scale cover. The scale cover of the adult female is 2-3 mm long, mussel-shaped, pure white, slightly convex and has two yellow-brown or translucent cast skins situated terminally. See Watson (2002) for an illustration of the adult female. The male scale cover, if present, is about 1 mm long, elongate and white with three longitudinal ridges and terminal, yellow or translucent, cast skins.
Beneath the scale cover, the body of the living adult female and the eggs are dark orange or red (Zahradník, 1990; Gill, 1997). When mounted on a microscope slide, the body of the adult female is elongate, 1.3-1.7 mm long, membranous and has a narrow prosoma. Gland spines and macroducts are present anterior to abdominal segment I. The pygidium has zygotic median lobes, inset and broadly rounded (with the inner margins longer than the outer margins) and any setae or gland spines between their bases are absent. Submedian macroducts are present on both the pygidial and prepygidial segments; those on segments III, IV and V are all of a similar size.
The adult male possesses one pair of colourless wings with very simplified venation; three pairs of legs; long, many segmented antennae; long genitalia; several pairs of simple eyes; and lacks mouthparts. See Bullington et al. (1989) for an illustration of the adult male.
DistributionTop of page C. pinifoliae is a temperate species that probably originated in North America. In spite of records published in Nakahara (1982) and Danzig and Pellizzari (1998), C. pinifoliae is not present in the UK (Watson, 2002). The species has not been recorded from Europe, Asia, Australia or the Pacific islands.
The distribution map includes records based on specimens of C. pinifoliae from the collection in the Natural History Museum (London, UK): dates of collection are noted in the List of countries (NHM, various dates).
C. pinifoliae has been intercepted at plant quarantine on pine trees on several occasions but has never become established in Bermuda (Hodgson and Hilburn, 1991; Bermuda Department of Agriculture & Fisheries, 1997).
Distribution TableTop of page
The distribution in this summary table is based on all the information available. When several references are cited, they may give conflicting information on the status. Further details may be available for individual references in the Distribution Table Details section which can be selected by going to Generate Report.Last updated: 10 Jan 2020
Risk of IntroductionTop of page The occurrence of a parthenogenetic/uniparental strain of C. pinifoliae increases the potential for this species to establish if it is introduced to a new territory. A single, unmated adult female could give rise to an established population if unchecked.
Hosts/Species AffectedTop of page C. pinifoliae has been recorded from hosts belonging to two families of evergreens: Taxaceae and Pinaceae (Borchsenius, 1966). In California it is common on species of Pinus (Gill, 1997).
Host Plants and Other Plants AffectedTop of page
|Pinus mugo (mountain pine)||Pinaceae||Main|
|Pinus resinosa (red pine)||Pinaceae||Main|
|Pinus sylvestris (Scots pine)||Pinaceae||Main|
Growth StagesTop of page Flowering stage, Fruiting stage, Vegetative growing stage
SymptomsTop of page C. pinifoliae may cause the foliage to turn yellow, then brown, and the branches may die (Kosztarab, 1990; Kosztarab, 1996). Feeding by the pest destroys the mesophyll cells, leading to chlorosis of the foliage. This chlorotic condition and/or light interception by the insects decreases the photosynthetic capacity of the foliage. The decline in assimilation rate reduces the vigour of severely infested trees (Walstad, 1972).
List of Symptoms/SignsTop of page
|Leaves / abnormal colours|
|Leaves / abnormal leaf fall|
|Leaves / external feeding|
|Leaves / necrotic areas|
|Leaves / yellowed or dead|
|Stems / dieback|
Biology and EcologyTop of page Apparently there are two races of C. pinifoliae, one is parthenogenetic and the other is biparental. In California, USA, the parthenogenetic race has one generation per year and overwinters as eggs; the biparental race has two generations per year and overwinters as gravid females (Gill, 1997). In California, USA, 53% of the population are male (Nur, 1990). In Iowa, USA, Burden and Hart (1989) found that at 18.5°C, there were 136 day-degrees accumulated to hatching and the time to 50% hatching was 17.25 days. The developmental threshold was between 10.8 and 11.8°C. Kosztarab (1963) mentions that there are two generations per year in Ohio, USA. In Virginia, USA, each female lays eight to 32 eggs, there are two generations per year, and overwintering is as eggs and females (Kosztarab, 1996).
On Pinus mugo in the USA (New York), C. pinifoliae infested only the lower quarter of the crown (DeBoo and Weidhaas, 1976). This may indicate that this scale species has a preference for the shade.
Walstad et al. (1973) reported that the stylets enter the needle through a stoma and terminate in the mesophyll tissue.
The crawlers are the primary dispersal stage. Mortality due to abiotic factors is high during crawler dispersal.
Natural enemiesTop of page
|Natural enemy||Type||Life stages||Specificity||References||Biological control in||Biological control on|
Notes on Natural EnemiesTop of page Burden and Hart (1990, 1993) discussed the natural enemy communities associated with C. pinifoliae in North America.
Means of Movement and DispersalTop of page Natural dispersal (non-biotic)
The crawlers are the primary dispersal stage. They walk up to a few metres, to new areas of the host plant, or from one plant to another if the plants are touching.
The crawlers are dispersed over longer distances by wind (Greathead, 1990) or animal/human agencies. The dispersal of sessile adults and eggs occurs through human transport of infested plant material.
Movement in trade
The dispersal of sessile adults and eggs occurs through human transport of infested plant material (Greathead, 1990).
Plant TradeTop of page
|Plant parts liable to carry the pest in trade/transport||Pest stages||Borne internally||Borne externally||Visibility of pest or symptoms|
|Bark||nymphs||Yes||Pest or symptoms not visible to the naked eye but usually visible under light microscope|
|Flowers/Inflorescences/Cones/Calyx||nymphs||Yes||Pest or symptoms not visible to the naked eye but usually visible under light microscope|
|Fruits (inc. pods)||nymphs||Yes||Pest or symptoms not visible to the naked eye but usually visible under light microscope|
|Leaves||adults; eggs; nymphs; pupae||Yes||Pest or symptoms not visible to the naked eye but usually visible under light microscope|
|Seedlings/Micropropagated plants||nymphs||Yes||Pest or symptoms not visible to the naked eye but usually visible under light microscope|
|Stems (above ground)/Shoots/Trunks/Branches||nymphs||Yes||Pest or symptoms not visible to the naked eye but usually visible under light microscope|
|Plant parts not known to carry the pest in trade/transport|
|Growing medium accompanying plants|
|True seeds (inc. grain)|
Wood PackagingTop of page
|Wood Packaging not known to carry the pest in trade/transport|
|Loose wood packing material|
|Processed or treated wood|
|Solid wood packing material with bark|
|Solid wood packing material without bark|
ImpactTop of page Tooker and Hanks (2000) describe C. pinifoliae as a common pest of conifers in the USA, especially in urban environments and Christmas tree plantations. It is considered to be one of the most serious pests of ornamental pine trees, especially Pinus mugo and Pinus sylvestris. Lal and Naji (1979) found that C. pinifoliae was the most injurious pest on pines in Libya. In California, heavy infestations are unsightly and reduce host vitality, weaken and kill branches, and sometimes the whole tree. This species can cause problems on Christmas tree plantations and is considered to be one of the most serious pests of ornamental pines (especially Scotch and mugo pines) in the USA (Kosztarab, 1996). Heavy outbreaks have been recorded after widespread spraying against mosquitoes (Gill, 1997), which presumably eliminated the natural enemies. Zahradník (1990) described C. pinifoliae as noxious or very noxious to conifers. Walstad et al. (1973) found that percentage reduction in chlorophyll content and in net photosynthetic rate were approximately equal to the percentage of foliage surface area covered by the scale insects. Feeding by the pest destroys the mesophyll cells, leading to chlorosis of the foliage. This chlorotic condition and/or light interception by the insects decrease the photosynthetic capacity of the foliage. The decline in assimilation rate reduces the vigour of severely infested trees (Walstad, 1972).
DiagnosisTop of page Microscopic examination of slide-mounted adult females is required for an authoritative identification to species. Williams and Watson (1988) described a method for preparing microscope slide mounts of Diaspididae.
Detection and InspectionTop of page The needles/foliage should be closely examined for mussel-shaped, pure white scale covers with terminal yellow-brown or translucent exuviae. The foliage should also be inspected for chlorosis and browning, in association with the scale infestation.
Similarities to Other Species/ConditionsTop of page Microscopic examination of slide-mounted adult females is required for an authoritative identification to species.
Chionaspis corni (dogwood scale, cochenille de cornouiller) could be misidentified as C. pinifoliae, but differs in having the median lobes divergent, with each one shorter than it is wide. In contrast, C. pinifoliae has median lobes that are not strongly divergent, and each one is longer than it is wide. These species also have different host plants, with C. corni feeding on Cornus species and C. pinifoliae feeding on Pinus species.
Prevention and ControlTop of page
Due to the variable regulations around (de)registration of pesticides, your national list of registered pesticides or relevant authority should be consulted to determine which products are legally allowed for use in your country when considering chemical control. Pesticides should always be used in a lawful manner, consistent with the product's label.Cultural control
Outbreaks of C. pinifoliae can be discouraged by increasing the structural and species diversity of the plants in ornamental landscapes and Christmas tree farms, to favour natural enemies (Tooker and Hanks, 2000).
Eliason and McCulloch (1997) found that the abundance and fecundity of C. pinifoliae varied on different varieties of Pinus sylvestris, being higher on the varieties, 'Riga' and 'Pike Lake Improved' compared with 'Belgium' or 'Land O'Pine'.
Natural enemies are important in helping to control C. pinifoliae populations. The mosquito control programmes that involve fogging with insecticide can cause outbreaks of C. pinifoliae by suppressing its natural enemies (Luck and Dahlsten, 1975). Unless scale populations have reached very high numbers, it is advisable not to use pesticides because these kill hymenopteran parasitoids at lower concentrations than are needed to kill the scales. The use of pesticides is likely to make the problem worse. If spraying is essential, the oil emulsion sprays are least harmful to the natural enemies (Nielsen, 1990).
ReferencesTop of page
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McClure M S, Fergione M B, 1977. Fiorinia externa and Tsugaspidiotus tsugae (Homoptera: Diaspididae): distribution, abundance, and new hosts of two destructive scale insects of eastern hemlock in Connecticut. Environmental Entomology. 6 (6), 807-811. DOI:10.1093/ee/6.6.807
McDaniel B, 1972. The armored scale insects of Texas (Homoptera: Coccoidea: Diaspididae). Part V. The tribe Diaspidini. In: Southwestern Naturalist, 16 321-340.
Mussey G J, Potter D A, 1997. Phenological correlations between flowering plants and activity of urban landscape pests in Kentucky. Journal of Economic Entomology. 90 (6), 1615-1627. DOI:10.1093/jee/90.6.1615
Nakahara S, 1982. Checklist of the Armored Scales (Homoptera: Diapididae) of the Conterminous United States., Washington, USA: USDA, Animal and Plant Health Inspection Service, Plant Protection and Quarantine. 110 pp.
Newstead R, 1907. List of other known African species of scale pests. In: Notes on the injurious scale insects and mealy bugs of Egypt; together with other insect pests and fungi. [ed. by Draper W]. Cairo, Egypt: National Printing Department. 15-16.
Tooker J F, Hanks L M, 2000. Influence of plant community structure on natural enemies of pine needle scale (Homoptera: Diaspididae) in urban landscapes. Environmental Entomology. 29 (6), 1305-1311. DOI:10.1603/0046-225X-29.6.1305
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Distribution MapsTop of page
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