Adult thrips are small, ellongated insects with typically long fringed wings. They measure about 1 mm, and have a greyish or yellow to brown colour. The two most common harmful species are the onion thrips (thrips tabaci) and the Western Flower Thrips (Frankliniella occidentalis).
The female thrips deposits eggs in the leaf tissue. The eggs hatch within a few days into very mobile nymphs which immediately begin to feed. After the second instar they drop on the ground to pupate. The total development from eggs to adult takes from 20 days at 20°C (68°F) to 12 days at 30°C (86°F). At sufficiently high temperatures one female thrips can produce up to 200 offspring. Thrips damage the crop by withdrawing the plant cell fluids. Empty cells are filled with air, causing a silvery app appearance, on which dark spots (excrement) are visible. Moreover, there exist many more symptoms of damage depending on the crop. For instance, thrips on very young cucumber fruits result in deformed fruits. In sweet pepper, they cause cosmetic damage on the fruits close to the calyx. In several ornamentals , flower damage on the fruits close to the calyx. In several ornamentals, flower damage through discoloration or deformation occurs. Only a few individual thrips are enough to cause damage. Moreover thrips are important vectors of several viruses (e.g. Tomato spotted Wilt Virus, TSWV).

For biological thrips control several Orius species are available, such as Orius laevigatus and Orius majusculus. Orius, also called the flower bug, is a small bug with a long mobile rostrum (feeding tube) that it can fold under its body. The red eyes are typical. The most commonly used species are brown to black white patches on the wings. Females are about 3 mm long, while males are slightly smaller.

A female Orius lays 1 to 3 eggs per day embedded in the plant tissue of petioles, stalk parts or veins on the underside of the leaf. Out of these colourless to white eggs of 0.4 mm, an Orius nymph emerges after about 5 days. The colour of the nymph depends on the species, but the red eyes are always conspicuous. A newly emerged Orius laevigatus is first colourless, but turns yellow after a few hours. In the later stages the nymph gradually gets the darker colour of the adult bug. In Orius laevigatus the first nymphal stages take each about 2 to 3 days at 25°C (77°F), while the fifth stage lasts for 4 to 5 days.

The total development time is about 3 weeks, but this can be much longer at lower temperatures. An adult pirate bug lives for 3 to 4 weeks. Adult Orius eat all thrips stages, while younger Orius nymphs only eat thrips larvae. Moreover, Orius also devours other preys such as aphids, spider mites or moth eggs. They always find their prey by touch, grab it with their front legs, insert their rostrum and drain their prey of its body fluids. They sometimes kill more insects than strictly necessary for their own feeding. Moreover, Orius also eat pollen, which enables them to build up a population in pollen bearing crops without the presence of thrips.
Some Orius species enter diapause at shorter day lenghts, while this does not seem to affect other species or strains.

Orius is used in a wide range of crops to control thrips. In pollen bearing crops (sweet pepper, gerbera, strawberry, eggplant, ...) Orius can be introduced preventatively as 1-2 pieces/m² as soon as there is enough flowering. In combination with other thrips beneficials (Amblyseius cucumeris and/or Amblyseius degenerans) the growing population will protect the crop during the whole cropping season.

In several greenhouse vegetable and ornamental crops, Orius can be introduced curatively in and around the hot spots at a rate of 5-10 bugs per m².
In cucumber, a crop that does not produce pollen, Orius majusculus can be introduced prevantively. This bug also eats other preys and can feed on plant saps. However, because sucseptibility to diapause, this species can only be used in summer time.
When using Orius, it should be kept in mind that Orius is sensitive to several pesticides. For instance, the application of teflubenzuron (Nomolt, Dart) can dramatically affect an Orius population.

• The predatory bugs are supplied per 500 pieces in a mixture of vermiculite and buckwheat, packed in a plastic bottle rovided with a yellow cap.
• Orius can be stored for a short time at a temperature of at least 8°C (46.4°F).

	As soon as the first thrips are spotted, the predatory bugs have to be introduced. In cultures such as sweet pepper and gerbera it is also possible to introduce preventatively as soon as the flowering starts. The predatory bugs also feed on pollen. Consult Biobest's introduction scheme concerning the number of Orius to be introduced.
	After delivery, the predatory bugs have to be introduced as soon as possible. If necessary, the amterial can be stored for a short while. Store the bottles vertically in a cool (at least 8°C, 46.4°F) and dark place.
	It is important to turn the bottle regularly and to shake it very slightly right before and during introduction to obtain an equal distribution.
	The material has to be sprinkled on the leaves. The material should stay on the leaves for several days, so that the predatory bugs have sufficient time to spread throughout the vegetation. Once Orius has settled in the vegetation, its nymphs and adults are easily spotted in the flowers.
	Introduce more predatory bugs (up to 10/m²) in thrips hot-spots.

Note: Several pesticides have a negative effect on Orius spp. Please be careful when controlling diseases and other pests. Constult the Biobest list of side-effects of pesticides on beneficial organisms. Only available in North-America!

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