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, membranousmembranous: with the same character as a membrane, typically used to refer to structures like wings that are clear and translucent like a membrane and translucent	Membranous membranous: with the same character as a membrane, typically used to refer to structures like wings that are clear and translucent like a membrane 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 abdomenabdomen:
  one of the three body segments in insects; the most posterior segment containing the heart, reproductive organs, and digestive organs
  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 rangehost range:
the range of species that a particular organism can feed on to achieve successful growth and reproduction
, 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 calyxcalyx:
whorl of residual flower parts that include the sepals, found at the stem end of a fruit
. After emergenceemergence:
used to describe the completion pupation that culminates in the appearance of the adult form of an insect
, 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