Greenhouse thrips

Scientific name

Heliothrips haemorrhoidalis (Thysanoptera: Thripidae)

Similar species

poinsettia thrips, Echinothrips americanus

Distribution

United States: Florida and California; also in greenhouses and interiorscapes throughout the United States.

Worldwide: Africa, Austria, Brazil, Central America, England, Finland, France, Germany, Italy, Palestine, and the West Indies; also in greenhouses and interiorscapes in other countries.

Thought to be native to South America.

Diagnostic characteristics

Adults

• 1.3 - 1.7 mm (0.05 - 0.07 in.) in length.
• Blackish-brown body with lighter posteriorposterior:
  orientation pertaining to the rear of the body
  abdominal segments and white legs.
• Abdomen abdomen:
  one of the three body segments in insects; the most posterior segment containing the heart, reproductive organs, and digestive organs
  golden in newly emerged adults.
• Four translucent 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.
• Antennae have eight segments.

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
  ).
• Mature larvae approximately 1 mm (0.04 in.) in length.
• Whitish larval stage with red eyes; turn yellowish in color with maturity but retain red eyes.
• Pre-pupa pre-pupa:
  the non-feeding last instar larva of insects that undergo complete metamorphosis
  and pupa are whitish to slightly yellow.
• Larvae resemble adults, but wingless.
• The larval abdomenabdomen:
  one of the three body segments in insects; the most posterior segment containing the heart, reproductive organs, and digestive organs
  is up-turned and has a dot of excrement on it. The excrement can cause spotting on the leaves.

Eggs

• White.
• Elongate and banana-shaped.

Hosts

Citrus hosts

All Citrus species and their hybrids.

Non-citrus hosts

A partial list includes:

• Acacia spp.
• avocado, Persea americana
• azalea, Rhododhendron spp.
• Begonia spp.
• cacao, Theobroma cacao
• coffee, Coffea spp.
• Cyclamen spp.
• Dahlia spp.
• Easter lily, Lilium longiflorum
• Ficus spp.
• grape, Vitis spp.
• guava, Psidium guajava
• Hibiscus spp.
• Magnolia spp.
• mango, Mangifera indica
• oak, Quercus spp.
• orchid, multiple genera
• Philodendron spp.
• Phlox spp.
• Pinus ssp.
• Pistacia spp.
• tea, Camellia sinensis
• Viburnum spp.

Host damage

Fruits

• Rind spotting or russetting on both immature and clustered mature fruit can also occur on fruit in which a stem is in direct contact with a fruit.

Leaves

• Mottled from feeding damage, causing discoloration between laterallateral:
  with an orientation pertaining to the side
  veins.
• Undersides of leaves have black spots of larval fecal material.
• Heavily damaged leaves turn yellow and drop.
• Infests older leaves, rarely colonizes soft or young leaves.

Biology

All life stages of greenhouse thrips are spent on the host planthost plant:
the plant the provides sustenance for an insect
. Greenhouse thrips can reproduce asexually. Eggs are laid singly and inserted into leaf or fruit tissue. The tip of the egg can usually be seen using a hand lens. Greenhouse thrips prefer high humidity and shaded areas of the plant. They infest older, mature foliage. The life cycle is 21 days. Temperatures below 0°C (32°F) or above 37.7°C (100°F) can cause significant mortality.

Comments

Thrips can be difficult to identify, and often a compound microscope is required. If unusual damage or new hosts are infested by thrips, a sample should be sent to a local extension agent or state diagnostic laboratory.

References

Australian Government - Department of Agriculture, Fisheries and Forestry: Sub-committee on Plant Health Diagnostic Standards. 2009. National diagnostic protocol for poinsettia thrips, Echinothrips americanus. (http://www.daff.gov.au/__data/assets/pdf_file/0014/1531400/ndp4-poinsettia-thrips.pdf).

Denmark, H.A. 2008. Featured creatures fact sheet: greenhouse thrips, Heliothrips haemorrhoidalis (Bouché) (Insecta: Thysanoptera: Thripidae). EENY-075. University of Florida. (http://www.entnemdept.ufl.edu/creatures/orn/thrips/greenhouse_thrips.htm).

Denmark, H.A., and T.R. Fasulo. 2008. Greenhouse thrips, Heliothrips haemorrhoidalis (Bouché). EENY-075. University of Florida. (http://edis.ifas.ufl.edu/pdffiles/IN/IN23200.pdf).

Diffie, S., G.B. Edwards, and L.A. Mound. 2008. Thysanoptera of southeastern U.S.A.: A checklist for Florida and Georgia. Zootaxa 1787: 45-62. (http://www.mapress.com/zootaxa/2008/f/zt01787p062.pdf).

Flint, M.L. (ed.). 2008. How to manage pests, U. C. Pest management guidelines: greenhouse thrips (http://ipm.ucdavis.edu/PMG/r107301811.html).

Authors

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