Thrips are so tiny you’ll need a magnifying glass to see them. They average about 1/25″ long. Color is anywhere from yellow to black. Males are wingless, females have four wings that are fringed. Adult females do not need males to reproduce. They appear only in very large groups, there’s never just a few of them.
Because they are so tiny, you rarely see the thrips, only the damage they have done. Like most of the worst garden bugs they do their damage by sucking juices out of the plant. You’ll often see the damage as wrinkled damaged flower petals.
Thrips have a preference for hiding in flower buds and a strong preference for lightly colored flowers. If they do attack the leaves of a plant, you’ll see the damage as streaks on the leaves.
They also like vegetables. They damage young vegetables and your full grown fruits will be scarred.
They are very hard to treat, but usually not enough of a problem to bother treating. Use either sevin dust or a systematic pesticide if you must.
Thrips have only recently become a problem for home gardeners in Houston. They’ve been moving here in greater numbers from the south eastern part of the country. Since Ike they have been seen in larger numbers. Keep your eyes out, you’ll likely see the damage rather than the thrips on your plant.