Cinara cupressivora

 
IDENTITY
Name:   Cinara cupressivora
Pest Authorities:  Watson and Vogtlin
Taxonomic Position:  Insecta: Homoptera: Aphididae
Sub-specific Taxon:  
Pest Type:   Insect
Common Name(s):
   Cypress aphid (English)
Synonym(s):
   Cinara cupressi (Buckton)
 
RISK RATING SUMMARY
Numerical Score:  9
Relative Risk Rating:  Very High Risk
Uncertainty:   Very Certain
RISK RATING DETAILS
Establishment Potential Is High Risk
The relevant criteria chosen for this organism are:  
  • Organism has successfully established in location(s) outside its native distribution
  • Suitable climatic conditions and suitable host material coincide with ports of entry or major destinations.
  • Organism has demonstrated ability to utilize new hosts
  • Organism has high inoculum potential or high likelihood of reproducing after entry.
Justification: Cinara cupressivora is established in sub-Saharan Africa, Colombia and the Indian Ocean island of Mauritius. It has also spread beyond the limits of its original Near Eastern-eastern Mediterranean Europe distribution as a result of extensive planting of Cupressus sempervirens in Italy and other Mediterranean European countries. This insect would find suitable hosts and climatic conditions near ports of entry across much of North America, especially in areas with warm, arid climates. It has adapted to a large number of new hosts including at least two new host genera. C. cupressivora adults are expected to have a high likelihood of reproducing after entry, especially the parthenogenetic forms.

Spread Potential Is High Risk
The relevant criteria chosen for this organism are:  
  • Organism is capable of dispersing more than several km per year through its own movement or by abiotic factors (such as wind, water or vectors).
  • Organism has demonstrated the ability for redistribution through human-assisted transport.
  • Organism has a high reproductive potential
  • Newly established populations may go undetected for many years due to cryptic nature, concealed activity, slow development of damage symptoms, or misdiagnosis.
  • Eradication techniques are unknown, infeasible, or expected to be ineffective.
  • Organism has broad host range.
Justification: Winged adults are capable of flying short distances although this is not considered an important means of spread. Both adults and nymphs are subject to dispersal by air currents, which can move populations from tree to tree. Ants have developed a symbiotic relationship with aphids of the genus Cinara and are known to move aphids to new locations on the same or neighboring trees to maintain vigorous colonies capable of producing copious amounts of honeydew on which the ants feed.

Colonies of giant conifer aphids are easily moved via planting stock. Extensive planting of conifers that are hosts of various species of Cinara and international transport of nursery stock is the primary human assisted means of spread of this group of insects. Cinara cupressivora has a high reproductive potential and reproduces at least part of the year by parthenogenesis. Populations could go undetected because of their small size and similarity to indigenous species of Cinara. Eradication is considered to be extremely difficult because of problems associated with detection and identification of this insect. Cinara cupressivora has a broad host range and would probably find any plant of the familiy Cupressaceae to be suitable host material.

Economic Potential Is Moderate Risk
The relevant criteria chosen for this organism are:  
  • Organism attacks hosts or products with significant commercial value (such as for timber, pulp, or wood products.
  • Organism directly causes tree mortality or predisposes host to mortality by other organisms.
  • Organism may cause loss of markets (domestic or foreign) due to presence and quarantine significant status.
Justification: Cinara cupressivora has caused extensive damage to plantations of Cupressus lusitanica and other Cupressaceae in sub-Saharan Africa where it has been introduced. It is also known to periodically damage host trees within what is believed to be its natural range. As a general rule trees of the family Cupressaceae are not widely used in forest plantation programs in North America. However, many host plants are important landscape materials and junipers are important windbreak species. The introduction of C. cupressivora could have serious impacts on the North American nursery industry.

Environmental Potential Is High Risk
The relevant criteria chosen for this organism are:  
  • Organism is expected to cause significant direct environmental effects, such as extensive ecological disruption or large scale reduction of biodiversity.
  • Organism may attack host with small native range.
Justification: Several species of Cupressaceae native to North America are hosts of Cinara cupressivora and are severely damaged by aphid feeding. Examples are Cupressus lusitanica, native to Mexico, C. arizonica native to the Southwestern U.S. and C. macrocarpa, which occurs naturally in two populations on the Monterrey Peninsula of California (Griffin and Critchfield 1972). Establishment of Cinara cupressivora in these areas could have devastating effects on trees with small distributions resulting in reduced biodiversity and ecological disruption.

 
HOSTS
Cinara cupressivora attacks conifers of the family Cupressaceae in the genera Cupressus, Juniperus, Chamaecyparis and Thuja indigenous to the northern hemisphere; Widdringtonia, restricted to central and southern Africa and Callitris, restricted to Australasia. Many of the species of these genera have been moved between continents because of their commercial and aesthetic values (Watson et al. 1999).

Host plants have differential susceptibilities to feeding by Cinara cupressivora and suffer varying degrees of damage. Studies in Malawi and Kenya rated a number of hosts according to their susceptibility to damage by this insect according to four classes (Odera 1991): Highly susceptible (H), Moderately susceptible (M), Slightly susceptible (S) Tolerant (T). This ranked host the following hosts: Callitris columellaris (=Callitris glauca) (M), Callitris preissii (H), Callitiris rhoboidea (H), Cupressus arizonica (M), Cupressus arizonica var. nevadensis (= Cupressus nevadensis (M), Cupressus lusitanica (= Cupressus lindleyi) (H), Cupressus lusitanica var. benthami (=Cupressus benthami) (H), Cupressus cashmiriana (T), Cupressus guadalupiensis var. forbesii (=Cupressus forbesii) (M), Cupressus funibris (M), Cupressus macrocarpa (H), Cupressus sempervirens (several cultivars S-H), Juniperus procera (T-M), Widdringtonia nodiflora (=Widdringtonia cupressoides) (M-H).

 
GEOGRAPHICAL DISTRIBUTION
Africa:
      Burundi, Kenya, Malawi, Mauritius, Morocco, Rwanda, South Africa, Tanzania, Zaire, Zimbabwe
Asia:
      Jordan, Syria, Turkey, Yemen
Cosmopolitan:
      Populations of Cinara cupressivora are presently found in Africa, Asia (Near East), Mediterranean Europe and one country in South America (Colombia). This insect is believed to have originated on one or more species of Cupressus or Juniperus, which occur in the northern portions of the Near East through to northern India and the southern end of the Caspian Sea. The most likely natural host is Cupressus sempervirens. Occurrences of this insect in South America, sub-Saharan Africa and Maritius are believed to be the result of accidental introductions (Watson et al. 1999).
Europe:
      France, Greece, Italy, Spain, United Kingdom
South America:
     Colombia
 
BIOLOGY
The genus Cinara is a large genus of conifer infesting aphids. Because of their relatively large size, they are collectively known as giant conifer aphids. According to Eastop (1972) approximately 200 species of Cinara are known. Approximately 150 species are indigenous to North America, 20 from Japan and other Asian countries and 30 from Europe (Ciesla 1991a).

The life cycle of many species of Cinara is complex. Adding to this complexity is the fact that Cinara cupressivora has been recognized as a separate species for only a short time (Watson et al. 1999) and much of the information on its biology and habits is reported under the designation Cinara cupressi.

During the summer months, only females are present and reproduce pathenogenetically. They give birth to live young. There are two forms of adults: a winged and wingless form. As cool weather approaches, both males and females are found and eggs are produced instead of live nymphs.

Eggs are deposited in rough areas on twigs and foliage, where they overwinter. Several generations are produced in a year and the life span of a single generation is about 25 days during the peak of the summer season.

Adults and immature insects occur in clusters of up to 80 individuals on the branches of host trees, where they suck the plant juices from the stem (Ciesla 1991 a,b).

Studies on the reproductive biology of Cinara cuppresivora in Jordan indicate that in warm climates, parthenogenic reproduction continues throughout the year. Females have an average life span of 21.9 days at 20 degrees C and 12 hours of alternating light and darkness. Between 8-9 generations per year are believed to occur in Jordan (Mustafa 1987).

Giant conifer aphids produce copious amounts of honeydew, which covers the branches and foliage. The honeydew provides a medium for growth of black colored fungi called sooty molds (Ciesla 1991b).

 
PEST SIGNIFICANCE
Economic Impact:    Adults and nymphs suck plant juices from the phloem tissue of host plants. Feeding causes desiccation of plant tissue. Aphid feeding, coupled with regular dry seasons, can cause branch dieback and tree mortality. Sooty molds associated with the cypress aphid causes foliage discoloration and interferes with photosynthesis and gas exchange (Ciesla 1991a, Ciesla et al. 1995).

In Kenya and other countries of eastern and southern Africa, Cinara cupressivora is an important pest of fast growing, exotic cypress plantations. Approximately 46% of Kenya’s industrial forest plantations are Cupressus lusitanica, which is highly susceptible to aphid feeding. This tree produces quality lumber when managed on a 30-year rotation. Intermediate cuttings provide posts, poles, pulpwood and fuelwood. This tree is also widely planted for windbreaks, ornamental hedges and living fences (Ciesla et al. 1995)

In the Mediterranean Region, Cinara cupressivora causes intermittent damage to Cupressus sempervirens. A recent outbreak was reported in Tuscany, Italy on both trees and cypress hedges in 1997 (Watson et al. 1999).

Environmental Impact:   The ability of Cinara cupressivora to feed on native African species of the family Cupressaceae, such as Juniperus procera and Widdringtonia nodiflora, could present a serious threat to the ecology of areas where stands of these species still occur. However, although Juniperus procera suffered significant foliar injury when Cinara cupressivora first appeared in Kenya in 1991, it soon developed a tolerance for the insect and damage became negligible (author’s observation).

Control:    Chemical, cultural and biological control tactics are available for management of damaging populations of Cinara cupressivora. Ground applications of various chemicals will provide effective short-term protection of cypress hedges and small ornamental trees but is impractical in forests. In Africa, observations indicate that cypress plantations established on good soils will be more tolerant of aphid infestations than those established on shallow, rocky soils. Young, fast growing plantations are less susceptible to damage than are mature plantations (Ciesla et al 1995). Therefore, proper site selection and timely harvesting of plantations should reduce losses.

Classic biological control has been used successfully against several introduced species of Cinara. For example, in South Africa, an introduction of the North American species, Cinara cronartii, was controlled by the introduction of a parasitoid of the genus Pauesia (Hymenoptera: Braconidae) (Kfir et al. 1985). These parasitoids tend to be species specific, however, and it is critically important to have a positive identification of the species of Cinara involved as well as a positive identification of the parasitoid. In northern Syria, populations of Cinara cupressivora are attacked by a parasitoid that may be, as yet, undescribed (Watson et al. 1999).

Larvae and adults of ladybird beetles (Coleoptera: Coccinelidae) and larvae of several species of syrphid flies (Diptera: Syrphidae) are natural control agents of Cinara cupressivora but apparently are not capable of controlling high populations.

 
DETECTION AND IDENTIFICATION
Symptoms:    General symptoms of giant conifer aphid infestation include the occurrence of copious quantities of honeydew and black sooty molds on the branches and foliage of host trees. Colonies of aphids are found on thin, well-shaded branches. The occurrence of ladybird beetle adults and larvae (Coleoptera: Coccinelidae) is often an indicator of aphid infestation as is the presence of ants, which tend the aphids and feed on the honeydew.

Morphology:    Giant conifer aphid adults range from 2-5 mm in size. They are typically dark brown in color and have long legs. Sometimes the bodies are covered with a powdery wax. They typically occur on the branches of host trees in colonies of 20 to 80 adults and nymphs. Both winged and non-winged adults can be found in the same colony.

Winged and apterous female adults are described by Watson et al. (1999). Separation of Cinara cupressivora from C. cupressi is difficult. In British populations, there is a fairly consistent difference between the adult apterous forms in the presence of pigmented sclerites on abdominal segment II. In the case of C. cupressivora, 85% have two sclerites on this segment whereas on C. cupressi,, only about 10% of the individuals have any scerites on abdominal segment II and less than 1% possess paired scerlites (Watson et al. 1999).

Testing Methods for Identification:    Examination of adults by a taxonomist with expertise in the aphid genus Cinara is required for positive identification.

 
MEANS OF MOVEMENT AND DISPERSAL
Winged adults are capable of flying short distances but this is probably not an important means of dispersal. All life stages are subject to dispersal by air currents. This insect’s present widespread worldwide distribution suggests that it is easily transported on live plant materials such as nursery stock.

 
BIBLIOGRAPHY
Ciesla, W.M. 1991a. Cyprus aphid, Cinara cupressi, a new pest of conifers in eastern and southern Africa. FAO Plant Protection Bulletin 39 (2/3): 82-93.
Ciesla, W.M. 1991b . Cypress aphid: a new threat to Africa’s forests. Unasylva 167, 42 (4): 51-55.
Ciesla, W.M.; Mbuga, D.K.; Ward, J.D. 1995. Ensuring forest health and productivity, a perspective from Kenya. Journal of Forestry 93(10): 36-39.
Eastop, V.F. 1972. A taxonomic review of the species of Cinara occurring in Britain (Hemiptera: Aphididae). Bulletin of the British Museum of Natural History and Entomology 27:101-186.
Griffin, J.R.; Critchfield, W.B. 1972. The distribution of forest trees in California. USDA Forest Service. Pacific Southwest Forest and Range Experiment Station, Berkeley, CA, Research Paper 82, 114 pp.
Kfir, R.; Kirsten, F.; Van Rensberg, N.J. 1985. Pauesia sp. (Hymenoptera: Aphididae), a parasite introduced into South Africa for control of the black pine aphid, Cinara cronartii (Homoptera: Aphididae). Environmental Entomology 14(5): 597-601.
Mustafa, T.M. 1987. Reproductive biology and population studies of the cypress aphid, Cinara cupressi (Buckton) and pine aphid, C. maritime (Dafour). Dirasat 14: 99-105.
Odera, J.A. 1991.. Some opportunities for managing aphids of softwood plantations in Malawi. Rome: FAO, Assistance to Forest Sector Malawi, MLW/86/020, 135 pp.
Watson, G.W.; Voegtlin, D.J.; Murphy, S.T., Foottit, R.G. 1999. Biogeography of the Cinara cupressi complex (Hemiptera: Aphididae) on Cupressaceae, with description of a pest species introduced into Africa. Bulletin of Entomological Research 89:271-283
 
AUTHOR(s)
Name(s):
William M. Ciesla
 
 
Name and Address of the First Author:
William M. Ciesla
Forest Health Management International
2248 Shawnee Court
Fort Collins, CO
USA 80525
 
CREATION DATE:        07/16/03
MODIFICATION DATE:        07/16/03

    
Selected images from Forestry Images (www.forestryimages.org)
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1307011

Infestation
in east Africa
Photo by James Denny Ward,
USDA Forest Service

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3948001

Life Cycle
Colony of nymphs and adults, near Muguga.
Photo by William M. Ciesla,
Forest Health Management International


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3948003

Damage
Cypress hedge damaged by cypress aphid infestation.
Photo by William M. Ciesla,
Forest Health Management International

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3948006

Damage
Damage to a forest plantation.
Photo by William M. Ciesla,
Forest Health Management International


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1307095

Damage
aerial view of damage in Kenya, Africa
Photo by James Denny Ward,
USDA Forest Service

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3943032

Biological Control
Mr Mututu, Kenya Forest Research Institute demonstrates technique for release of Pauesia parasitoides for biocontrol of cypress aphid, western Kenya
Photo by William M. Ciesla,
Forest Health Management International