Citrus thrips

Scientific name

Scirtothrips citri (Thysanoptera, Thripidae)

Other common names

bean thrips

Similar species

other species in the genus Scirtothrips

Distribution

United States: Arizona, California, and Nevada; potentially also occurring in the southeastern United States as well.

Worldwide: Mexico.

Native to the western United States and Mexico.

Diagnostic characteristics

Adults

• Yellow body.
• Females measure 0.6 to 0.9 mm (0.02 - 0.04 in.) in length.
• Males are similar in appearance but somewhat smaller.
• Head head:
  one of the three main body segments in insects; the anterior-most segment containing the many sensory structures including the eyes, antennae, and mouthparts
  is wider than long.
• Antennae with eight segments, segments 3 - 8 are grey.
• Both sexes have four wings with numerous fringes surrounding each wing, folded back over the thoraxthorax:
  one of the three main body segments in an insect, located between the head and abdomen, where the wings and legs of the insect attach
  and abdomenabdomen:
  one of the three body segments in insects; the most posterior segment containing the heart, reproductive organs, and digestive organs
  when at rest.

Immatures

• Two larval instars, pre-pupapre-pupa:
  the non-feeding last instar larva of insects that undergo complete metamorphosis
  (3rd instarinstar:
  immature stages (larva or nymph) of insects in between molts
  ), and pupa (4th instarinstar:
  immature stages (larva or nymph) of insects in between molts
  ).
• Light orangish-yellow to white body.
• Larvae resemble adults but wingless.

Eggs

• 0.2 mm (0.008 in.).
• Elongate and banana-shaped.

Hosts

Citrus hosts

All citrus species and their hybrids.

Non-citrus hosts

Broad host rangehost range:
the range of species that a particular organism can feed on to achieve successful growth and reproduction
including:

• alfalfa, Medicago sativa
• blueberries, Vaccinium spp.
• cotton, Gossypium spp.
• fir, Abies spp.
• grape, Vitis spp.
• laurel, Laurus spp.
• Rhus spp.
• Rosea spp.

Host damage

Fruits

• Feeding punctures young fruit leaving characteristic ring of grey scarring on the rind.

Leaves

• Damage young leaves, resulting in leaf distortion.
• Silvering on leaf surface.
• Brown frassfrass:
  pellets of very dry excreta produced by some insects
  markings.

Biology

Eggs are deposited within young, growing leaves, stems, or fruit. Females are capable of laying up to 250 eggs. Eggs deposited in the fall can overwinter. First and second instars feed on leaves and young fruit. The feeding on young fruit results in cosmetic scarring of the rind. Third and fourth instars are quiescent "pupal" phases that do not feed and may leave the plant to develop in the litter or soil. Citrus thrips have been reported to complete 10 - 12 generations per year.

References

Dreistadt, S.H., P.A. Phillips, and C.A. O’Donnell. 2011. Pest notes: Thrips. UC ANR Publication 7429. IPM Education and Publications, University of California Statewide IPM Program.(http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn7429.html).

Haviland, D.R., S.M. Rill, J.G. Morse. 2009. Southern highbush blueberries are a new host for Scirtothrips citri (Thysanoptera: Thripidae) in California. Florida Entomologist 92: 147-149. (http://www.fcla.edu/FlaEnt/fe92p147.pdf).

Hoddle, M.S., L.A. Mound, and D. Pena. Thrips of California. CBIT Publishing, Queensland. (http://keys.lucidcentral.org/keys/v3/thrips_of_california/Thrips_of_California.html).

Grafton-Cardwell, E.E., J.G. Morse, N.V. O'Connell, P.A. Phillips, C.E. Kallsen, and D.R. Haviland. 2009. UC IPM pest management guidelines: Citrus. UC ANR Publication 3441. IPM Education and Publications, University of California Statewide IPM Program. (http://www.ipm.ucdavis.edu/PMG/r107304111.html).

Kerns, D., G. Wright, and J. Loghry. 2004. Citrus arthropod pest management in Arizona. University of Arizona, Cooperative Extension Service. (http://ag.arizona.edu/crop/citrus/insects/citrusthrips.pdf).

Authors

Weeks, J.A., A.C. Hodges, and N.C. Leppla