Spirea aphid

Scientific name

Aphis spiraecola (Hemiptera: Aphididae)

Other common names

green citrus aphid

Similar species

apple aphid, Aphis pomi

cotton or melon aphid, Aphis gossypii

Distribution

United States: widespread throughout the U.S.

Worldwide: cosmopolitan, most citrus growing regions.

Diagnostic characteristics

Adults

• 1.2 - 1.7 mm (0.047 - 0.067 in.) in length.
• Uniform yellowish-green to green body, pale brown headhead:
  one of the three main body segments in insects; the anterior-most segment containing the many sensory structures including the eyes, antennae, and mouthparts
  , and pale brown legs and antennae.
• Winged forms have a dark brown middle body segment (thorax) with a green abdomenabdomen:
  one of the three body segments in insects; the most posterior segment containing the heart, reproductive organs, and digestive organs
  .
• Pear-shaped body with two black cylindrical tubes (siphunculi or corniclescornicles:
  paired, triangular-shaped tubes projecting from the rear of an aphid abdomen; also referred to as siphunculi <a href="http://idtools.org/id/citrus/pests/morphology.php?state[]=abdomen"></a>
  ) on the posteriorposterior:
  orientation pertaining to the rear of the body
  of the abdomenabdomen:
  one of the three body segments in insects; the most posterior segment containing the heart, reproductive organs, and digestive organs
  .
• Winged and wingless forms exist. Winged forms have four transparent wings.
• Antennae are approximately half the length of the body.
• A fleshy stub (cauda) at the extreme posteriorposterior:
  orientation pertaining to the rear of the body
  of the insect is round at the point (apex). It has 6 - 12 hairs (setae). The caudacauda:
  a v-shaped structure extending from the rear of the aphid abdomen <a href="http://idtools.org/id/citrus/pests/morphology.php?state[]=abdomen#abdomen"></a>
  is constricted at the base, closest to the abdomenabdomen:
  one of the three body segments in insects; the most posterior segment containing the heart, reproductive organs, and digestive organs
  .

Immatures

• Yellow-green.
• Shape resembles adults, but slightly smaller.

Eggs

• Glossy black.

Hosts

Citrus hosts

• clementine, Citrus clementina
• grapefruit, Citrus paradisi
• rough lemon, Citrus jambhiri
• sweet orange, Citrus sinensis

Non-citrus hosts

• apple, Malus domestica
• hawthorne, Crataegus spp.
• pear, Pyrus communis
• pomegranate, Punica granatum
• Spirea spp. (primary host)
• quince, Cydonia oblonga

Host damage

Flowers

• Infested flower buds may fall off the plant.

Fruits

• Honeydew honeydew:
  the sugar-rich waste product excreted by aphids, mealybugs, and scales insects as a result of feeding on the phloem of plants
  excreted by aphids coats the outside of fruits and leaves, and promotes the growth of sooty mold fungus that inhibits photosynthesis, weakens the plant, and makes fruit unattractive.

Leaves

• Feed on the underside of new growth.
• Heavy infestation may result in severe curling and distortion.
• Spirea aphids are capable of transmitting Citrus tristeza virus (CTV)(see Comments section).

Biology

Eggs overwinter on various plant tissues, including pruning scars, spurs, and terminals. Spirea aphids are capable of reproducing both asexually (parthenogenesis) and sexually. The sexual forms have only been seen in East Asia and North America. Because the aphids produce live young, they can build large populations quickly. The first generationgeneration:
the time it takes for an insect to develop from egg to adult
in the spring tends to be winged individuals. Subsequent generations are primarily wingless. Their maximum growth rate is at 27°C (75.2°F). Spirea aphid colonies are often tended and protected from predators and parasitoids by ant colonies.

Comments

Spirea aphid was formerly known as the green citrus aphid, Aphis citricola, and is an important viral vector. Spirea aphid transmits several viruses, including Citrus tristeza virus (CTV), Papaya mosaic virus, and Papaya ring spot virus. CTV causes quick decline of citrus, seedling yellows, and stem pitting disease, depending on the infecting strain of virus and root-stock. Mexican lime, Citrus aurantifolia, is the best indicator of CTV infection. Some rootstocks, such as trifoliate orange, are tolerant of CTV.

All phloem-feeding, honeydew-producing insect pests have the potential to be tended by ants. The ants feed on the honeydewhoneydew:
the sugar-rich waste product excreted by aphids, mealybugs, and scales insects as a result of feeding on the phloem of plants
excreted by the pest and protect the pest from natural enemies. This protection can disrupt biological control programs.

References

Blackman, R.L. and V.F. Eastop. 2007. Taxonomic issues pp. 11-12. In H. M. van Emden, and R. Harrington (eds.) Aphids as crop pests. CAB International, North America, Cambridge, MA.

Fasulo, T.R., and S.E. Halbert. 2009. Aphid pests of Florida citrus. (http://edis.ifas.ufl.edu/pdffiles/CH/CH05500.pdf).

Fraval, A., E. Fèvre, R. Coutin, C. Minost, and V. Laporte. 1997. Green citrus aphid, spiraea aphid fact sheet. (http://www.inra.fr/hyppz/RAVAGEUR/6aphspi.htm).

Koizumi, M. 2001. Citrus tristeza virus: symptoms and control. (http://www.agnet.org/library/tn/2001003/).

Komazaki, S. 1993. Biology and virus transmission of citrus aphids. Technical Bulletin ASPAC/FFTC. (www.agnet.org/library/tb/136/tb136.pdf).

Miyazaki, M. 2001. Important aphid vectors of fruit virus diseases in tropical Asia. (http://www.agnet.org/library/tn/2001001/).

Reuther, W. 1989. Citrus industry: crop protection, postharvest technology and early history of citrus research in California. Division of Agriculture and Natural Resources. University of California.

Walgenbach, J. 2007. Southeastern apple production, entomology: green apple aphid / spirea aphid. (http://www.ces.ncsu.edu/fletcher/programs/apple/entomology/insects-mites/GAASPAfact.html).

Walker, K. 2007. Spiraea aphid (Aphis spiraecola) Pest and diseases image library. (http://www.padil.gov.au).

Authors

Martin, K.W., A.C. Hodges, and N.C. Leppla