The life cycle of a thrip is fast; about 2 weeks, depending on species and
temperature. Generally speaking, the warmer it is, the faster the life
cycle. All but one stage has piercing/sucking mouthparts. They can esialy
get through screens and come inside a greenhouse or indoor growing area from
outside populations. In some species all stages have wings, from the newly
hatched instars to the adult, and in other species wings are missing during
some stages, leaving them a period of only a couple days where they must
crawl/walk to find food.

As you know they are tiny. Without a loop, it is not easy to tell a fungus
gnat from a thrip. The easy difference is in where they feed. Fungus gnats
larvae feed almost exclusively on decaying material near the upper surface
of soil/pots/potting media/scummy ponds/refrigerator drip pans, etc.....
Adults fungus gnats exist only to fly and mate and don't have mouth parts.
Few if any species of fungus gnats eat live plant roots, but there are
plenty of other 'decomposing' larvae that do and they all look like each
other to the giant human eye observing them.

Thrip Eggs are laid on plant tissue, usually leaf and more often flower
tissue and newly hatched larval instars will begin to feed on any part of
the plant which presents sap/fluids containing nutrition. Populations tend
to rapidly take on the coloration of whatever they are feeding on and this
leads to common names, like "Green" or "Yellow" Tobacco Thrip, or "Purple
Dendrobium Thrip," etc... when in reality they may not be plant specific
species; just rapidly adjusting generational camouflaging eveolved as a form
of protection.

Within about 72 hours the larva will molt through two stages all the while
eating whatever tissue they are living on.

Once the third stage instar begins they stop eating some may even develop
wings, fly off or simply
crawl down into moderately or well decayed potting media to pupate. Like
fungus gnats, this instar requires potting media that is very moist and on
the decomposed side in order to do well. Dry and/or new potting media will
make it hard for both fungus gnats and 3rd stage thrip larvae to survive in
it.

The hatching pupa are responsible for biting humans and causing skin
reactions: they literally will pierce and suck any tissue that is moist,
including skin.

The fourth stage pupa, is where they turn into fully mature adults ready to
mate and reproduce. Females
lay eggs which will hatch even if not fertilized. Eggs produced from
fertilized females will
yield offspring of either sex; those laid by unfertilized females will hatch
into only males.

I write all this because you must address a thrip problem on all parts of
the plant and environment where any moist living or decaying tissue, (plant
or animal) exists. :-)

"Jack" wrote in message
oups.com...
Thanks, I have alot of algea growing in this pot, I removed all the old
moss before repotting, Guess that I'll have to get some phytosan and
drench it in malithion, actually all my orchids because where there is
one thrip in one plant you have thrips in all your plants. Wow I hate
those suckers.


Jack

BTW I have an Onc. Pacific Skys that is in spike, I guess that I am
used to phals and catts because I am getting impatient for it to bloom
and all it is doing is branching out the spike.