Thrips
are very small insects with a range of 1/32 to 1/8 inch in length. They vary
in color from yellow to orange to black and have small feathery wings with which
they fly. They are very weak fliers and rely on wind currents to travel distances
greater than a few feet. Thrips eggs are laid inside of the plant tissues and
squeeze out just before they hatch. A thrips takes anywhere from 8 to 30 days
to develop to the adult stage depending on temperature.Thrips are unique in that they have what are called rasping-sucking mouthparts. If you take the needle-like mouthpart of the mosquito, shorten it and add strong teeth to the end, you arrive at the mouthparts of the thrips. Thrips use their mouthparts to slash surface cells on a plant's stem, leaves, or fruit, and drink the juices that ooze from those wounds. The onion thrips (Thrips tabaci Lindeman) causes silvery streaks on onion leaves from its feeding activities. Most thrips damage is similar to that described on onion leaves. However, some thrips will attack berries and remove enough juices from the berries to cause a sour flavor. Some thrips species can also transmit tomato spotted wilt disease from plant to plant. Humans cannot be infected by this disease. Most thrips are attracted to flowers, especially magnolias and daisies (composites). Thrips are easy to see inside of the flower near the center. Some thrips species are predaceous on other small insects as well.
Thrips don't bite on purpose. They are just "tasting" you to see if you are a plant. They do not inject venom and the discomfort is only temporary. Of course you're not a plant and they are probably disappointed (Who knows?). Most people who are bitten by thrips are usually sitting downwind from something that's blooming. In the spring and summer, Chinese Tallow trees, magnolias, and wildflowers are loaded with thrips because of their blooms.
Thrips usually move from vegetables and flowers in the spring to wild grasses and native plants in the summer as drier conditions prevail.
Controlling thrips is fairly simple. Strong streams of water will provide some control, but insecticidal soaps will provide a more reliable means of managing this pest. Other controls include malathion, permethrin, and pyrethrin sprays. Check the product label to make sure it is approved for thrips control on the area in which you plan to use it. Thrips rarely require control efforts, but there are a variety of means available to do the job.
Literature Reference: Drees and Jackman. A Field Guide to Common Texas Insects. Gulf Publishing Company, Houston, Texas, 1998. (ISBN: 0-87719-263-4)
Back