This tool is part of the Citrus Resource

Citrus Pests

 

Thrips

 

Scientific name

 

Order Thysanoptera

Similar species

 

Thrips can be easily mistaken for small insects such as aphids and psyllids. Each insect can be easily distinguished by the overall body shape, mouthparts, and wing texture.

Thrips Aphids Psyllids
Mouthparts Rasping-sucking Piercing-sucking Piercing-sucking
Wing texture Fringed If present, membranous and translucent Membranous and either translucent or mottled
Body shape Elongate and flattened Pear-shaped with a pair of cylindrical rods on the rear end Cicada-like

Diagnostic characteristics

 
Adults
  • Smallest size - 0.6 mm (0.02 in.).
  • Largest size - 2 mm (0.079 in.).
  • Females are typically larger than males.
  • Slender and elongate body shape.
  • Bright yellow to dark brown in color.
  • Rasping-sucking mouthparts.
  • Short antennae with 4 to 9 segments.
  • Antennae are either monochrome or have grey to yellow alternating bands.
  • Compound eyes present.
  • Three ocelli (simple eyes) create a triangular shape called the ocellar triangle.
  • Either wingless (apterous) or winged (alate).
  • Winged species have two pairs of fringed wings that lay flat on the abdomen when at rest.
  • Wings are either translucent or have light and dark banding.
  • Walking (gressorial) legs present.
  • Legs are either white to yellow or have light and dark banding.
  • The 'feet' or tarsi are 1 - 2 segmented.
  • Each tarsus has 1 - 2 claws.
Immatures
  • Smallest size - 0.5 mm (0.008 in.).
  • Largest size - 1 mm (0.04 in.).
  • Granulate body texture.
  • Lemon yellow to white body.
  • Some species have red eyes that fade closer to maturity.
  • Nymphs resemble wingless adults during first two instars.
  • Several species develop either external or internal wings during the first two instars.
  • Third and fourth instars are either quiescent pupal stages with internal wing development or pre-pupal and pupal stages with external wings.
Eggs
  • Smallest size - 0.075 mm (0.003 in.).
  • Largest size - 0.2 mm (0.008 in.).
  • Egg shape is similar to a bean, banana, or kidney, depending upon the species.
  • Creamy white color.

Hosts

 
Citrus hosts

Several thrips have all citrus species and their hybrids listed as hosts, including the chilli thrips, citrus thrips, Florida flower thrips, greenhouse thrips, and South African bean thrips. See individual fact sheets for more detailed information.

Non-citrus hosts

Thrips have a broad host range, including weeds and economically important crops. See individual fact sheets for more detailed information.

Host damage

 
Flowers

Thrips feeding cause flowers, petals, pistils, and stamens to appear bronzed and brittle. Heavy infestations can lead to flower drop.

Fruit

Thrips puncture the fruit epidermis, leaving a characteristic scarring in the form of a grey ring. Fruits may also appear bronzed. Premature fruit drop can occur during heavy infestations.

Leaves

Thrips feeding turns leaves bronze or silver. Leaves may curl upwards and appear brittle. Thrips may leave excrement (frass) in the form of brown dotting on the undersides of leaves.

Biology

 

Thrips females lay one to several eggs at a time. Individually laid eggs are inserted into leaf or fruit tissue while egg masses are deposited on leaves, stems, or fruit. During the first two instars, nymphs can feed on the leaves, foliage, or young fruit. Third and fourth instars do not feed and enter a quiescent phase or a pre-pupal and pupal stage. Pupae can be found on leaves, soil, or under the calyx. After emergence, adults resume feeding by lancing a plant cell and sucking in exuded plant fluids.

References

 

Belkin, J. 1976. Fundamentals of Entomology: A manual for introductory courses. American Biological Supply Company. Baltimore, Maryland.

Eaton, E. and K. Kaufman. 2007. Thrips pp.36. In Field guide to insects of North America. Houghton Mifflin Company. New York, New York.

Triplehorn, C. and N. Johnson. 2004. Thysanoptera pp. 333- 335. In Borror and DeLong's Introduction to the study of insects. 7th ed. Brooks/Cole Cengage Learning. Belmonte, California.

Authors

 

Guerrero, S., J.A. Weeks, and A.C. Hodges

 

Citrus Pests
Content last updated June, 2012
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