Biological Pest Control for thrips

Sal Schettino (sals@coyote.rain.org)
Sat, 19 Mar 1994 19:37:23 -0800 (PST)

Last year I lost over 80% of my Avocado crop to thrips. The adult
Western Flower Thrips is a tiny,slender insect with narrow hairy wings.
These insects in their immature stages are translucent and golden-yellow
in color and are characterized by the apperance of wing,pads and
shortened erect antennae in the papal stage. In the field it is very
difficult to distinguish between the two species (Western Flower Thrips
Frankiniella occidentalis and Onion Trips). Thrips lay their eggs within
the leaf tissue and flower. The adult and the larve feed on the plant
causing the typical silvery flecking on the flower and leaves and the
Avocados themselfs so stores will not buy them. The larvae pupate and
fall to the ground. 3 to 9 days later depending on the temperature
adults will emerge. At 20 C the Thrips life cycle is completed in 22 days.

So this is the target pest. So far I have a choice between 3 different
Thrips Predators. Orius (Orius spp.) Pirate Bugs -Amblyseius
cucumeris-and Thripobius Semilevteus (Boucek).

Has anyone released any of these? I leave in Cal. and being interested
in Sustainable Agriculture I would like to find a Biological Control that
will live here and one that I donnot have to buy every year. I would
like a sustainable population! one that overwinters here where it hardly
never drops below 30 Far.
Thripobius sounds the most useful. Other farmers are useing it and have
told me it seem to work. Thripobious is a hymenopterous parasite that
attacks greehouse thrips, It was imported from two sources by Dr. James
McMurty field collection in Brazil and from Australia where it was
discovered as a laboratory culture. Thripobius development takes 21 days
from egg to adult under ideal conditions (65-75 degrees F.) The parasite
attacks nymphal stage rate of 40 or more greenhouse thrips per adult
Thripobious. anyone know any more about this guy. I'm going to buy some
and test them in a hot spot in april. Cannot aford too many. The nice
thing about this one is it does not move away to fast. Maybe only a tree
or two apart . Not like some predators when you let them out the run
this one hangs around. I would like to here more about him. Like does he
have a Diapause photoperiod how does he handle our winters. I have heard
lots of good things about this guy.
Orius (Orius spp.) Three native species of pirate bugs, Orius tristicolor
(the minute pirate bug) O. insidiousus and O. minutus are currently being
Researched at Applied BioNomics. Although pirate bugs appear to have
preferences for particular prey,they are general predators and will
consume a variety of pests including mites,thrips,aphids,and small
caterpillars. The effect of pirate bugs on most of these pests is not
knows however O. tristicolor has shown to effectively control western
flower thrips populations in cucumber and sweet pepper greenhouses. Has
anyone used them outside. Life Cycle-The total generation time for Orius
tristicolor in greenhouses at 70 F.21 C is approximately 3 weeks. Eggs
are laid in plant tissue(main stem,leaf veins,flowers or petioles) with
the top of the egg sticking out of the leaf. /The eggs hatch in 4-5 days
and grow through 5 instars. The nymphs are colorless at first, then
gradually turn nymphal stage may be 0.5 mm 1/50 inch long and the last
nymphal stage is only 1/10 inch long. Adults are 2-2.5 mm or 1/10 inch
long mostly black in color with small brown markings on the wings.
Adults live 3-4 weeks. All stages run quickly and adults are good
flyers. They will move efficiently throughout the greehouse to locate
pests. Orius kills it prey by piercing them with its mouthparts and
sucking out the body fluides. If prey is abundant Orius kills more
thrips than it needs to survive. Anymore info about this guy. I'm going
to have to try him just to watch and learn.
The last one Amblyseius cucumeris is being used with considerable success
as a Trips predator . This mite which feeds on the youngest larval
stages of Thrips consumes an average of only 1 or 2 per day. These
predatory mites are considerable smaller than the two spotted spider mite
and are difficult to see with the naked eye.
So the cucumeris eats the youngest and the Orius eats the oldest . I
think the Orius will eat the cucumeris . I have to lick this thrips
organicly so all ideas are welcome. Also I need to get rid of scale but
one bug at a time.
Help!