Cypress aphid

Type Description

"Aphididae family species are small soft-bodied insects that live in different parts of plants and feed on plant sap. Their bodies vary in size between 1-10 mm and are usually pear-shaped.

The bodies of aphids are segmented and these segments are more or less distinct. The body consists of three parts: head, thorax and abdomen. The distance between the front of the head and the beginning of the tail gives the body length.

The members of C. cupressi are brownish gray aphids covered with long, fine hairs. It differs from most other Cinara species in being shorter than the basal width of the second segment of the hind tarsus. There are numerous bristles on the subgenital plate (Eastop, 1972; Blackman and Eastop, 1994).
The likely composite character of C. cupressi makes it difficult to generalize about its biology and ecology. Adult females may be wingless or (sometimes) winged."

Habitat

"Watson and others (1999) suggested that Cinara cupressivora may have evolved on Cupressus sempervirens, which naturally occurs at relatively high altitudes just south of East Greece and the Caspian Sea. When it accidentally reached East Africa, this aphid spread in high-altitude forests on Cupressaceae hosts (Ciesla, 1991).

Different populations within C. cupressi exhibit different host preferences. Cinara sabinae is almost exclusively observed on Juniperus scopulorum. Cinara canadensis has been identified on Juniperus virginiana. Cinara cupressi has been recorded on Cupressus species in Europe, J. scopulorum, J. virginiana, T. occidentalis, and Thuja plicata (Watson et al., 1999).

It is estimated that aphids emerged approximately 280 million years ago, with the greatest increase in species diversity occurring with the emergence of angiosperms. They are generally found in temperate regions but are distributed worldwide. Currently, about 70% of the existing aphid species belong to the Aphidinae and Drepanosiphinae subfamilies. The Greenideinae and Hormophidinae subfamilies make up about 7% of the existing aphid species. Species belonging to these families are generally distributed in Southeast Asia and Australia.

C. cupressi is likely a native leaf aphid of North America and Syria. It is reported to cause significant damage and has recently spread in some regions of Europe, Africa, South America, and the Middle East.

The likely composite character of C. cupressi means that the distribution list provided here may represent the distributions of potentially different species. Cinara sabinae is only recorded from the USA (Arizona, Colorado, and Utah); Cinara canadensis from Canada (Ontario) and the USA (Pennsylvania); and Cinara cupressi from California and England (Watson et al., 1999); Lachnus juniperinus is recorded from Poland. The known distributions of C. cupressi and Cinara cupressivora only overlap in England (Watson et al., 1999).

The following entry dates are related to countries where aphids have been reported to cause significant damage or as recent introductions. Countries where the relevant population may be native, damage has not been reported, or the entry date is too early to be known, have not been included in this list.

In Europe: Italy, before 1978 (Binazzi, 1978); Belgium and France, before 1980 (Latteur and Grasso, 1980; Rabasse and Grasso, 1980); Bulgaria, before 1988 (Scheurer, 1991); and Portugal, before 1996 (Ilharco, 1996).

In the Middle East: Israel, 1980 (Mendel and Golan, 1983); Jordan, before 1987 (Mustafa, 1987); and Yemen, before 1999 (Watson et al., 1999).

In Africa: Malawi, 1986 (Ciesla, 1991); Tanzania, 1987 (Ciesla, 1991); Burundi, 1988 (Ciesla, 1991); Rwanda and Uganda, 1989 (Ciesla, 1991); Kenya, Democratic Republic of the Congo (Zaire), and Zimbabwe, 1990 (Ciesla, 1991); South Africa, before 1993 (Watson et al., 1999); Libya and Morocco, before 1994 (Al Najar and Nefrya, 2000; Watson et al., 1999); and Mauritius, 1999 (Watson et al., 1999).

In South America: Colombia, before 1991 (Ciesla, 1991); and Brazil (Sao Paulo), 2000 (Sousa Silva and Ilharco, 2001).

Looking at the situation in Turkey, it was determined that the first record was reported from Pazarcık district of Kahramanmaraş province in 2001 (Aslan and Uygun, 2005). In a study conducted in Kastamonu province, it was reported that C. sempervirens on the road to Taşköprü was detected on 01.06.2004 (Unal and Ozcan, 2005)."

Reproductive Information

The likely composite character of C. cupressi makes it difficult to generalize about its biology and ecology. Adult females may be wingless or (sometimes) winged. In countries with cold winters, at least some populations (e.g. Cinara sabinae and Lachnus juniperinus) produce sexual females and winged males to overwinter as eggs (Gillette and Palmer, 1924; Watson et al., 1999). In milder climates, Cinara cupressivora and Cinara cupressi reproduce asexually (by parthenogenesis) all year round. The number of generations produced each year depends on host quality and environmental conditions. Studies have reported 11 to 12 generations per year in Italy (Binazzi, 1997) and 8 to 10 generations in Jordan (Ciesla, 1991). For C. cupressivora, Kairo and Murphy (1999) established life tables at different temperatures and found that development and fecundity were highest at 25 °C (the highest temperature tested).

Lifecycle

"Cyclic parthenogenesis is observed in the life cycle of aphids. Aphids reproduce parthenogenetically in spring and summer and sexually in fall.

Aphids lay their eggs on woody plants in the fall. Overwintering on this host, the eggs give rise to fundatrixes. Fundatrixes reproduce viviparously and form fundarrixgenias. These can be winged or wingless and reproduce viviparously. The winged forms migrate to the second host in late spring. In the second host they reproduce viviparously and form colonies, which are virginopars. In late summer, virginopars form winged and wingless parthenogenetic females. These form wingless females and winged wingless males on the first host. After mating, the eggs are laid by the female on a woody plant for overwintering. They remain there until conditions are favorable."

Nutrition Information

Members of C. cupressi avoid strong light and dense colonies in the shade with up to 80 aphids per 10 cm branch. Aphids feed on the bark of small twigs and branches in the inner and lower parts of the main canopy (Ciesla, 1991). The excreted sugary sap covers surfaces, including foliage. Sooty mold often develops in these sugary deposits.

General Impact Information

"Aphids, due to their small size and ability to hide among plant tissues, often go unnoticed by humans, even though they can cause significant damage to plants when living in colonies. As a result:

1. They cause growth and development to stop, yellowing and drying of plants, color changes, and deformities in organs such as leaves, fruits, and shoots by sucking the plant sap, which is necessary for their development and reproduction. They also cause changes in plant metabolism and the formation of various structures such as galls and nodules with the toxic substances they give to the plant while sucking the plant sap.
2. Aphididae species in the superfamily Aphidoidea excrete large amounts of honeydew and sugary substances while feeding on plants. Through these substances, saprophytic fungi develop on the plant, leading to the formation of sooty mold, and the leaves become unable to perform photosynthesis.
3. It has been observed that photosynthesis, respiration, and transpiration rates decrease in plants invaded by aphids.
4. Aphids cause various plant diseases by indirectly carrying viruses and spreading infections to other plants.
5. They generally cause yield and quality losses in agricultural products.
In the initial heavy infestation of branches in plants, the branch tips die off while aphids move inward and continue to feed on live tissue. In sensitive hosts such as Cupressus lusitanica, if protective measures are not taken, the entire tree can die (Ciesla, 1991). In very tall, narrow species like Cupressus sempervirens, dieback starts at the outer edges of the lower canopy and spreads upward (Inserra et al., 1979).

It has not yet been determined whether the damage caused by the cypress leaf aphid is due to mechanical damage, the tree's excessively sensitive response to attack, or the toxicity of the aphid's saliva (Inserra et al., 1979).

Since the 1960s, many juniper and cypress stands have been severely damaged by C. cupressi in many countries. Dispersed outbreaks have been reported in western and southern Europe. Examples include Southern England in 1988 (Winter, 1989) and Italy in 1977 and 1997 (Inserra et al., 1979; Binazzi, 1997), as well as Jordan (Mustafa, 1987). The population identified as Cinara cupressivora has been recorded to cause damage in Colombia and Mauritius (Watson et al., 1999). Since its initial entry point in Malawi, Africa, it has spread to southern and eastern Africa, causing significant damage in eight countries (Ciesla, 1991; Murphy et al., 1994). The main juniper species commercially grown in Kenya and other East African countries, preferred for its rapid growth rate and excellent shape, is Cupressus lusitanica. This species is highly susceptible to feeding by the cypress leaf aphid (Ciesla, 1991). Observation of a mature C. lusitanica stand in Kenya for 2 years showed that 12% of the trees died directly (Orondo and Day, 1994).

In the southern and eastern Africa region, the cypress leaf aphid killed a total of 27.5 million dollars worth of cypress trees in 1991, resulting in an annual loss of 9.1 million dollars in growth increase (Murphy et al., 1996)."

General Management Information

"Cultural Control: Cultural methods are used to combat aphids, including the use of particle film, synthetic mulch (straw), loose organic mulch (straw), pruning, adjusting water balance, adjusting fertilizer use, adjusting crop density, mixing crop types, removing alternative host plants for aphids including residues of productive plants, allowing the growth of non-productive plants, planting alternative host plants for aphids, creating feeding and egg-laying plants for aphids, ensuring that weeds remain among crop plants, and continuing crop rotation to maintain weeds (Wratten et al., 2007).

Chemical Control: Aphids are an important target group for pesticide manufacturers to develop new insecticides. Chemical control is carried out against aphids by selecting aphicides that are effective through systemic, fumigant, and contact routes (Dewar, 2007).

Cypress aphids live in the depths of shade because they avoid bright light. As a result, it is very difficult to reach them through topical applications of insecticides.

Due to variable regulations regarding pesticide registration, it is necessary to check the national registered pesticides to determine which products are legally allowed for use in your country when considering chemical control against aphids. Pesticides should always be used in a manner consistent with the product label.

Host Plant Resistance: The resistance of plants to aphids varies depending on the plant species, and is due to structures and substances within the plants themselves. For example, certain components found in plants such as tomatoes and potatoes make these plants resistant to certain aphid species (Kok-Yokomi, 1978; Simmons et al., 2005; Novy et al., 2002). These properties include substances that prevent aphids from colonizing (antixenotic substances) and substances that adversely affect aphid reproduction (antibiosis) (Van Emden, 1978). At Muguga Research Station, Kenya, arboretum infestation created a natural experiment. Observations on the impact of infestation on different tree species in the arboretum showed a wide range of tolerance among different species (Obiri, 1994). Thuja spp. and Cupressocyparis leylandii were the most tolerant, while Widdringtonia and Callitris species were the least tolerant. In the genus Cupressus, the most tolerant species are Cupressus torulosa, Cupressus funebris and Cupressus arizonica, while the most susceptible are Cupressus benthamii (Cupressus lusitanica var. benthamii), Cupressus lusitanica (the main commercial species grown in Kenya) and Cupressus lindleyi (Cupressus lusitanica var. lusitanica). Results with hybrid trees have shown that resistance breeding through hybridization can offer a long-term solution to the aphid problem.

A mature Cupressus lusitanica stand study in Kenya showed that the degree of aphid damage varied from one tree to another (Orondo and Day, 1994). C. lusitanica seedlings from open-pollinated seeds of 18 families were subjected to cypress aphid attack to determine the genetic basis and inheritance of resistance (Kamunya et al. 1997). Progeny of some highly susceptible trees were highly resistant, indicating that resistance was transmitted from resistant neighbors. The results showed that there is a strong additive genetic control for resistance that can allow effective selection and reproduction. It was suggested that a cycle of selection could ensure a resistant population. A later study found that selection for resistance to aphid damage was unlikely to have negative effects on economically important traits such as stem height and diameter (Kamunya et al. 1999).

Another resistance survey of 32 C. lusitanica families in Tanzania identified the best families in Kenya and Uganda. Ten families were recommended for use in breeding to broaden the genetic base of future forests in the region (Mugasha et al. 1997).

Biological control
The biological control strategy consists of three main categories (Van Driesche and Bellows, 1996):
i) Classical method: The release of natural enemies not previously present in the area.
ii) Augmentation: Increasing the number of natural enemies present in the area. Natural enemies do not naturally reach sufficient numbers in time to control the target pest.

iii) Conservation: Maintaining the development of naturally occurring populations of natural enemies through habitat control or modification of the behavior of natural enemies (Powell and Pell, 2007). Coccinellidae of Coleoptera; Chrysopidae and Hemerobiidae of Neuroptera; Syrphidae and Cecidomyiidae of Diptera; Anthocoridae of Hemiptera are the main predators. Adhilenidae of the superfamily Chalcidoidea and Aphidae of the superfamily Ichneumonoidea of Hymenoptera are important parasitoids, while Zygomycota and Ascomycota are important fungal pathogen groups (Völkl et al., 2007).

Pauesia juniperorum, a biological control agent, was brought to Malawi from Europe (Chilima, 1995) and reduced the impact of cypress aphid there. It was later introduced to Kenya and Uganda (Day et al., 2003). Day et al. (2003) reported that evaluation of the outcome of this introduction started in Kenya and was successful in Uganda.

Chilima and Owour (1992) list the native natural enemy species found attacking or associated with cypress aphid in Kenya. Most of these predators are almost certainly generalists and are unlikely to be well adapted to coniferous plant pests exotic to the region (Murphy et al., 1994).

In Italy, natural enemies such as coccinellids, cirophytes and neuroptera, even when present in large numbers, have not been able to prevent damage caused by cypress aphid (Inserra et al. 1979)."

General Pathway Information

"The natural distribution of cypress aphids is overcrowding and flight of winged forms produced several times each year in response to environmental cues (Kairo and Murphy, 1999). Winged aphids are strong fliers and can be carried long distances by the wind. Aphids are also very well camouflaged against tree bark and are easily transported in planting stock (Ciesla, 1991).

Cypress aphids can be carried on imported plant material (Remaudière and Binazzi, 2003)."

Notes

In its winged stage, the cypress aphid increases its local distribution thanks to its flight ability and wind. There is no known use of the species in the literature.

References