Minute Pirate Bug aka. Orius insidiosus
Target Pest: Western flower thrips, Onion thrips
Orius has been shown to be an effective control of western flower thrips in cucumber and sweet pepper greenhouses. It is not effective for thrips control in tomatoes. Orius are generalist predators that consume a variety of pests including mites, aphids, and small caterpillars. They are most effective for pests with life stages that inhabit flowers such as flower thrips. Optimum conditions are temperatures over 59 °F (15 °C) with relative humidity over 60%. Typical greenhouse temperatures of 64-82 °F (18-20 °C) are suitable for Orius development.
0.5 - 1 per 10 square feet
60% + RH
59 °F and more
Target Pest: Western flower thrips (Franklinella occidentalis), Onion thrips (Thrips tabaci)
Description: Orius is a predatory bug that feeds on many species of small, soft-bodied insects and pollen. Adults are 2-2.5 mm long, mostly black with lighter markings on the wings. Nymphs are colorless when they hatch, darkening to yellow and dark brown as they grow. They grow from 0.5 mm long to 1.8 mm long. Orius moves quickly at all stages. Orius adults are good flyers and move efficiently throughout a greenhouse to locate prey. Adults are attracted to, and can often be found in flowers.
Use in Biological Control: Orius has been shown to be an effective control of western flower thrips in cucumber and sweet pepper greenhouses. It is not effective for thrips control in tomatoes. Orius are generalist predators that consume a variety of pests including mites, aphids, and small caterpillars. They are most effective for pests with life stages that inhabit flowers such as flower thrips. Optimum conditions are temperatures over 59 °F (15 °C) with relative humidity over 60%. Typical greenhouse temperatures of 64-82 °F (18-20 °C) are suitable for Orius development.
Life Cycle: A complete life cycle takes approximately 3 weeks at 70 °F (21 °C). Cooler temperatures and lack of prey slow the development. Sex ratio in the population is about equal, with slightly fewer (45%) females. Females lay 2 eggs per day, with an average of 30 eggs in their lifetime. Eggs are laid in plant tissue with the top of the egg sticking out of the leaf. Eggs hatch in 4-5 days.
Orius nymphs grow through 5 stages over 2-3 weeks, until they moult to the adult stage. Adults live for 3-4 weeks. Orius will diapause in the fall when day lengths are less than 12.5 - 14 hours. Orius pierce its prey with its mouthparts and sucks out the body fluids. If prey is abundant, this predator kills more thrips than it needs to survive. The presence of pollen favors development of Orius as it acts as an alternative food source.
Introduction Rates: Orius needs a food source before they can lay eggs, therefore they should only be released when thrips populations are present or when pollen is available (i.e., from flowers of sweet peppers).
General Introduction rates: 5000-10,000 Orius per hectare (2,000 - 4,000 per acre).
Greenhouse cucumbers: 0.5 Orius per plant or m2 . Apply one a week for 2 weeks or 1-4 Orius per plant in hot spots when thrips populations are established.
Sweet peppers: 2000-3000 Orius per 1000 yd2 (m2 ) in hot spots.
Two releases that are spaced 2 weeks apart will usually establish Orius throughout the greenhouse. Control is achieved proportionately sooner with higher release rates. Four to six weeks are required after release of Orius before thrips populations decline markedly.
Note: Orius adults are attracted to yellow sticky traps, however, if traps are placed at a rate of 1 trap per 100 plants or more, this should not be a problem. When more than 4 Orius are being caught on traps per week, it is an indicator that their density is high and that enough Orius are in the crop to bring thrips under control.