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Pest Information Guide: Six-Spotted Thrips Scolothrips sexmaculatus (Pergande)

Jeffrey D. Cluever and Hugh A. Smith

Morphology

Figure 1. 
Figure 1. 
Credit: Jeffrey D. Cluever, UF/IFAS
  1. Extremely long setae on pronotum.
  2. Ocellar III setae extremely long and not arising between posterior ocelli.
  3. Three dark dots present on each forewing.
  4. Extremely long setae present on forewing.
  5. Comb on tergite VIII absent.
  6. Ctenidium on tergite VIII absent (arrow indicates spiracle).

Appearance

Egg

The eggs are minute and found inside plant foliage. These are unlikely to be seen.

Larvae

Light in color. Usually not identified.

Pupal Stages

The prepupa is recognized by the presence of wing buds and antennae that are straight. The pupa also has wing buds but the antennae are pulled back over the head. These stages are not usually identified.

Adult

Light in color. Its most distinctive feature is the six dark dots present on the forewings. Other distinctive features are the extremely long setae on the pronotum and forewings.

Other Diagnostic Features

Include ocellar III setae (major setae arising near the ocelli) that do not arise.

Life Cycle

Scolothrips sexmaculatus exhibits all the life stages common to terebrantian thrips: the egg, larva I, larva II, prepupa, pupa, and the adult. The length of each life stage and the number of progeny produced varies according to temperature and prey species.

At 25°C (77°F) when reared on a bean leaf substrate and a diet of Tetranychus urticae (twospotted spider mite), it takes 13.3 days to complete development from egg to adult. The individual stages are as follows:

  1. The female lays an egg into the foliage; 5.8 days later it hatches.
  2. The larva I and larva II stages feed on their prey for 2.5 and 2.3 days respectively.
  3. The non-feeding prepupa and pupa last 2.7 days collectively before the emergence of the adult.

At this temperature a female can lay about 200 eggs in her lifetime.

Prey and Distribution

Scolothrips sexmaculatus feeds on pest mites including spider mites (Acari: Tetranychidae), European red mite (Panonychus ulmi), and the cyclamen mite (Phytonemus pallidus). Cannibalism may occur if prey are scarce.

Prey Consumption Rate

Larva

10 mite eggs/day

Adult

60 mite eggs/day.

Origin

North America

Geographic Distribution

North America. S. pallidus and S. sexmaculatus are present in Florida and may be the same species.

Further Reading

Diffie, S., G. B. Edwards, and L. A. Mound. 2008. "Thysanoptera of the southeastern U.S.A.: A checklist for Florida and Georgia." Zootaxa 1787: 45–62.

Hoddle, M.S., L.A. Mound, and D. Paris. 2012. Thrips of California. CBIT Publishing, Queensland. http://keys.lucidcentral.org/keys/v3/thrips_of_california/Thrips_of_California.html

Pakyari, H., Y. Fathipour, and A. Enkegaard. 2011. "Effect of temperature on life table parameters of the thrips Scolothrips longicornis (Thysanoptera: Thripidae) fed on twospotted spider mites (Acari: Tetranychidae)." Economic Entomology 104: 799–805.