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Orius
insidiosus Minute Pirate Bug, Thrips Predator by Syngenta
Bioline PO Box 1555, Ventura, CA 93002 800-248-2847 *
805-643-5407 * fax 805-643-6267 questions bugnet@rinconvitova.com orders orderdesk@rinconvitova.com www.rinconvitova.com |
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Target
pests
Western flower thrips (Frankliniella occidentalis)
Onion thrips (Thrips tabaci)
Description
‘Orius’ is a predatory bug (Family
Anthocoridae) that feeds on many species of small, soft-bodied insects.
·
Adults are 2-2.5 mm (1/10 inch) long, mostly black with
lighter markings on the wings.
·
Nymphs are colorless when they hatch, darkening to yellow,
then dark brown as they grow. They grow from 1/50 inch (0.5 mm) long up to1.8
mm (<1/10 inch) long.
All stages of Orius move very
quickly. The adults are good flyers and move efficiently throughout a
greenhouse to locate prey. Adults are attracted to, and often found in,
flowers.
Use
in Biological Control
·
Orius has been shown to be an effective control for western
flower thrips in cucumber and sweet pepper in greenhouses (flowering plants
that produce pollen. 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) and
humidities are suitable for Orius development.
·
Orius lays a large proportion of its eggs in (side) shoots.
Avoid unnecessary loss of these eggs by introducing after removing side shoots.
·
Native to North and South America
Monitoring
Tips
·
Orius adults and older nymphs are easy to see in cucumber
and pepper flowers, where they are feeding on thrips and pollen.
·
Both adults and younger stages can be found on leaves and
along stems, but they are more difficult to find.
·
Thrips shrivel after being eaten by Orius, and are therefore
difficult to see in the crop.
Life
Cycle
A complete life cycle takes
approximately 3 weeks at 70° F (21° C). Cooler
temperatures and lack of prey slow development.
·
Sex ratio in the population is about equal, with slightly
fewer females than males (45% females).
·
Females lay 2 eggs per day, with an average of 30 eggs in
their life time. Eggs are laid in plant tissue (main stem, leaf vein, flowers
or petioles) with the top of the egg sticking out of the leaf. Eggs hatch in
4-5 days. Females stop laying when the daylight is less than 12-14 hrs.
·
Orius nymphs grow through 5 wingless 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 11 hours.
Orius pierces its prey with its mouth
parts and sucks out the body fluids. If prey is abundant, Orius kills more
thrips than it needs to survive. The presence of pollen favors development of
Orius as it acts as an alternate food source.
Product
Information
Orius are usually sold as adults,
packaged in containers with buckwheat hulls or other materials. This provides
the adults with hiding places, which reduces cannibalism during shipping.
Release the adults by gently shaking
them onto individual plants or by opening the containers in the greenhouse and
allowing the insects to disperse.
Introduction
Rates
Orius need 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)
in groups of 25-50 insects to encourage mating
General Introduction rates
·
2,000 - 4,000 Orius/acre (5,000 - 10,000 Orius/hectare) use
higher numbers in hotspots.
Specific
Crops
·
Greenhouse cucumbers - 0.5 Orius/plant or 0.5/10 ft2
(m2), weekly, for 2 weeks.
or
1 - 4 Orius/plant in hot spots, when thrips populations are established.
·
Sweet peppers - 2 - 3 Orius/10 ft2 (m2)
in hot spots. Two releases, 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/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 enough Orius are in
the crop to bring thrips under control.
For Best Results
·
Until thrips populations are established, use the predatory
mite Cucumeris (Amblyseius cucumeris)
on cucumber. On pepper use the predatory mite Degenerans (Amblyseius degenerans) as soon as pollen is present.
·
To prevent Orius from diapausing from mid-August through
March supplemental lighting must be provided to increase day length to 14 hours
or longer.
Using
Pesticides
For effects of pesticides on Orius see
Pesticide Toxicity page.
Avoid the use of systemic insecticides
or pesticides with long residual action.