Minute Pirate Bug, Orius insidiosus.jpg

The predatory bug Orius laevigatus is the most widely used Orius species for the biological control of thrips.

Pirate Bug (Orius spp.)

The genus Orius is represented by very tiny true bugs commonly known as minute pirate bugs and flower bugs. Their common names are representative of their small size and favorite hangout while on plants. Insect predators of the genus Orius are polyphagous which means they are generalist predators that feed on a variety of prey.

Orius is a predatory bug that feeds on many species of small, soft-bodied insects. Orius pierces its prey with its mouthparts and sucks out the body fluids of its prey. If prey is abundant, Orius kills more thrips than it needs to survive. The presence of pollen favors development of Orius, as it is an alternate food source. Orius can consume 5-20 thrips per day.

Adults are black and white and are about 2-2.5 mm (1/10 inch) long. The nymphs are first colorless, then later become yellow to brown. All stages have red eyes. The eggs are embedded in soft plant tissue and are not very visible. The fresh growing tips and side shoots are choice spots and the release of Orius should be done after side shoot trimming is done if applicable. All stages of Orius move quickly. Adults are great flyers and move efficiently to locate prey. The adults are attracted to flowers. Under ideal conditions each female adult could lay up to 45 eggs over a 2-week period.

 

Target Pest:
Thrips, Spider Mites, Whiteflies, Aphids.

This video is documents various techniques for releasing the thrip destroyer, Orius insidiosus

Release Rates:
Introduce the beneficial as soon as you receive them. If storage is necessary, keep them at 10°-15°C (50°-59° F) and do not store in bottle for more than 8 hours.. Preventative introductions are only done in crops that produce pollen. To release, open the bottle and gently tap onto the foliage of infested plants. Concentrate the bulk of them at release points on or near the most heavily infested plants.

General release:
5 per 10 sq.ft. or 2,000-4,000 per acre.

Specific crop:
Greenhouse – .5 Orius per plant or Sq. ft. for 2 weeks
1-4 Orius per plant in hot spots, when thrips populations are established.

Two releases spaced two weeks apart will usually establish Orius.

Lifespan:
A complete life cycle takes approximately 3 weeks. Sex ratio is usually 1:1. Females lay 2 eggs per day, and average about 130 eggs in their lifetime. Egg to adult usually takes 2-3 weeks. Cooler temperatures and lack of prey will slow development. Orius nymphs grow through 5 instars over 2-3 weeks, until they molt to the adult stage. Adults live for 3-4 weeks. Orius will diapause in the fall, when day lengths are less than 12 hours.

Strategic Considerations:
Orius works perfectly together with other thrips predators such as Amblyseius cucumeris and Amblyseius degenerans. Avoid the use of systemic insecticides or pesticides with long residual action. Supplying these predators with certain flowering or pollen producing plants at or near the release site may increase their egg laying activity.

Selected References

Cornell University. A Guide to Natural Enemies in North America.

Minute Pirate Bug: A Beneficial Generalist Insect Predator. Veronica Johnson and Cerruti Hooks. University of Maryland Dept. of Entomology