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Shop > Beneficial Insects > Thrip Controls

Thrips are important greenhouse pests. They have a wide host range consisting of hundreds of plant species that includes all the major greenhouse vegetable crops and many commonly grown ornamentals. Thrips are very small in size (1–3 mm) and live cryptically such as in the flower bud, new leaves or growing points of plants. This pest has readily developed resistance to pesticides and there are few or no effective pesticides to control them.

Pest Description

Thrips are tiny, slender insects with fringed wings. Depending on the species, they are about 1–3 mm in length when fully developed. Adults vary in colour from greyish, dark brown or black through to yellow or straw brown. Immature thrips are usually white or yellow with red eyes.

The most common species found in greenhouses is western flower thrips (WFT), Frankliniella occidentalis which can cause damage by direct feeding (silvery appearance on leave surface) and can cause the transmission of plant viruses. WFT are 1.5 to 2 mm in length (females larges than males). The bodies are yellowish brown in colour and they appear to have a dark strip on the top surface of the back. The eyes are red. The larvae are white (early instars) and become yellow as they age. WFT feeds on almost any flowering plants including carnations, chrysanthemums, gerberas, geraniums, marigolds, pansies, and roses are the major host plants.

Onion thrips adults are smaller in size (1.2 to1.3 mm) and are a fairly uniform yellowish brown colour. Their eyes are grey and they have grayish antennae. These Thrips resemble WFT and are difficult to distinguish. They feed on a wide variety of vegetable plants, small grains, field crops and weeds.

Echinothrips adults are larger thrips (1.6 mm) and are very dark brown in colour. The wings are also dark with white band across the shoulders. They feed on many ornamentals and It has been found on poinsettias, cucumbers, and peppers.

Chilli thrips adults are smaller (adults up to 1.2 mm) and pale yellow to almost white in colour. This thrips feed on more than 100 plants from about 40 different families which include vegetable, fruit and ornamentals.


Thrips feed with piercing/sucking mouthparts resulting in the removal of cell contents, leaving white/silvery feeding scars on leaves or translucent spots and streaking on flower pet¬als. Feeding is also characterized by tiny, black, fecal deposits on leaf surfaces.

Thrips can also vector (transmit) a family of viruses known as tospoviruses, the most important of which are impatiens necrotic spot virus (INSV) and tomato spotted wilt virus (TSWV). Tospoviruses have a host range of hundreds of plant species and cause a wide variety of symptoms including stunting, stem and leaf necrosis, distortion, chlorotic and nerotic leaf lesions and concentric ring spots and line patterns.

Beneficial Insects and Tips

Soil Stage Controls

  • Stratiolaelaps scimitus and Gaeolaelaps gillespiei: target a variety of prey such as thrips pupae, fungus gnat and shorefly larvae and springtails in soil.
  • Dalotia coriaria: is a predatory rove beetle that feeds on pests in the soil.
  • Steinernema feltiae :S. feltiae is most commonly recommended for control of fungus gnats (sciarid flies), thrips and leafminer.

Foliage Stage Controls

  • Orius insidiosus: is a generalist predator, feeding on various soft-bodied insects and mites, but thrips are its preferred food source. Both the adults and immature stages of Orius are predatory.
  • Amblyseius swirskii: swirskii feeds on thrips, whiteflies (greenhouse whitefly and Bemisia), and spider mites. It is known to perform better when fed on a mixed diet of both whitefly and thrips. It also feeds on pollen and can establish on crops in the absence of pests if there is a pollen source available.
  • Neoseiulus cucumeris is a predatory mite, previously known as Amblyseius cucumeris. Because N. cucumeris feeds only on the first larval stage, it can take 4-6 weeks for control to be evident, longer if thrips were well-established before N. cucumeris was introduced. N. cucumeris can harass older Thrips which can result in better control1.
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