- 1 Thrips Overview
- 2 How To Get Rid Of Thrips
- 3 Frequently Asked Questions
Terrible thrips! They invade the garden, sucking the juices out of leaves and stems and the life from your plants. Thrips cause scarring on fruit and vegetables and spread plant diseases like the tomato spotted wilt. Finding them in your plant beds is never a good thing, because by the time you find them, they’re often widespread.
Thankfully, there are some things that we can do to wipe out these pests and keep them at bay. I’ll go over what thrips are, what they do to your plants, and how to stop them.
Interestingly, both the singular and plural name for this pest is “thrips”. So it doesn’t matter if you’re referring to one thrips or a whole bunch!
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Organic Products To Eliminate Thrips:
Environmental Products To Eliminate Thrips:
Thrips Preventative Options
|Common Name(s)||Thrips, corn lice, thunderbugs, storm bugs, freckle bugs, thunderblights, harvest bugs, corn flies|
|Scientific Name(s)||Thousands of species in the order Thysanoptera|
|Plants Affected||Most commercially-farmed crops, many ornamental plants, trees, etc. Extremely diverse food selection.
There are many different varieties which prefer particular plants, such as onion thrips, tobacco thrips, cannabis thrips, rose thrips, avocado thrips, and citrus thrips.
|Common Remedies||Insecticidal soaps, neem oil, pyrethrin sprays, diatomaceous earth, kaolin clay, predatorial insects (ladybugs, lacewings, Trichogramma wasps, minute pirate bugs, thrips predator mites), sticky traps.|
What Are Thrips?
Thrips are long, slender insects that are rarely over a quarter-inch in length in their adult form. Yellow, black, or brown are common colors for adult thrips, and the larval stages tend to be yellow or green. These insects fall into the Thysanoptera order of insects.
Some varieties have fringed wings, but they are not strong fliers. Other thrips have mostly vestigal wings that don’t work at all.
There are over 4500 species of thrips, and some indications put it closer to 6000.
While there are varieties which wreak havoc on your plants, other types are actually beneficial. These beneficial species will attack and consume other insects, including other varieties of thrips. It’s difficult to tell the good ones from the bad, so most people opt to simply eradicate them all.
Life Cycle of Thrips
Female thrips are capable of producing eggs asexually if they lack a mate. Unlike most caterpillar species, they eat or rasp out a hollow in plant matter in which to lay their eggs, providing them shelter from potential predators.
The eggs are shielded from weather conditions in the soft tissues of the plant. When they hatch, there’s a food source at hand.
Most thrips go through two larval stages as nymphs before becoming adult. A few types have more larval stages, some reaching as many as five. Once they have reached the end of their nymph development, they will pupate and become adult. This process can take 8-15 days during warm weather, and as long as a month in colder weather conditions.
Some varieties of thrips can enter diapause. Diapause is almost like suspended animation, and thrips can survive like this as adults, pupae, or eggs.
The average thrips lives its entire lifetime in about a 45-day span.
Here’s an interesting video on these pests’ life cycle!
Common Habitats For Thrips
Throughout the winter months, thrips bury themselves under leaf cover, dig underground, or occasionally infest locations such as the walls of houses or sheltered parts of fences.
In the warmer months of the year, they live on and around the plants that they are consuming. On trees, that will often be in the leaves and bark of the tree. On other plants, it will be on the leaves or stems or in the flower blossoms.
What Do Thrips Eat?
Most of the pest types of thrips live on plant juices. These thrips will bite or saw their way into the plant stem to drink from it, or use their syringe-like mouths to extract liquid from leaves.
Thrips infest most commercial food crops. They can scar fruit or vegetables on the surface, causing damage to the fruit. There are also thrips varieties that will infest roses, trees, or other ornamental plants.
As thrips lay their eggs inside plant stems or stalks, it can be hard to find the eggs. It’s important to check for adult or nymph stages on blossoms, leaves, or stems.
There are some thrips varieties that are beneficial. These species tend to feast on other pest types, including mites and aphids. They also will eat plant pollen when pests are not available. It’s very difficult to distinguish between the pests and the good thrips.
Generally, if you see no thrips damage on your plants, but you do see the thrips themselves, you probably have the good type and do not need to be concerned.
How To Get Rid Of Thrips
One of the interesting aspects of thrips is that some species are developing resistances to particular pesticides. The pesticides will still kill these pests, but it may take longer to wipe them out.
If you follow the below steps, you should be able to eliminate thrips from your yard and protect your plants from future attack!
Organic Thrips Control
Insecticidal soaps may be necessary for moderate infestations of thrips. A product such as Safer Soap applied heavily on all surfaces of the plant will kill what thrips are on the plant and discourage new thrips to move in.
Especially bad outbreaks may require more powerful options. At that point, use a pyrethrin spray such as Safer Brand Yard & Garden Spray, which combines pyrethrin with fatty oils to smother and poison thrips.
Environmental Thrips Control
Eliminate grass and weeds around your plant beds. Thrips can live in grassy or weedy locations. Similarly, remove any plant debris around your plants to remove a potential home.
Keep your greenhouse clean. A cleaned greenhouse that is bare of plant debris is less likely to develop thrips.
Don’t forget your beneficial insects! There is a type of mite called the thrips predator mite which will happily eat the thrips, as well as spider mites and pollen. The minute pirate bug also eats thrips. Ladybugs and lacewings are both great at reducing thrips populations. Finally, the Trichogramma wasp is known to destroy some varieties of thrips.
Inspect new plants before introducing them into your yard or your greenhouse. These irritating little pests will spread quite rapidly from the new plants to older ones.
It may be wise to keep plants separated in a quarantine area away from your greenhouse or garden for a couple weeks so that you can keep an eye on them.
Thrips tend to avoid plants which have been liberally dusted with diatomaceous earth or kaolin clay. Diatomaceous earth feels like knife blades to small insects. Kaolin clay coats the plant’s foliage with a gritty dust that insects do not like.
Adult thrips can be caught on sticky traps. Hanging these around your plants will help to reduce the population numbers.
Frequently Asked Questions
Q: Will nematodes help keep my thrips population down?
A: Yes and no. As thrips often overwinter and pupate in the soil, beneficial nematodes can be helpful at wiping out any underground.
Since most of the population is made up of adults or nymphs who are above-ground, nematodes should not be your only beneficial insect addition. However, they won’t hurt, and they can help kill off a number of garden pests!
Q: Do thrips bite?
A: Yes, they do. While thrips aren’t harmful to humans or our pets, people who have sensitivities to bug bites might experience some slight irritation.
Usually, washing the bite in warm to hot water with soap will reduce any itching it may cause. It’s more of an annoyance than something to be concerned about.
Q: Are there greenhouse thrips?
A: Thrips are almost as much of a problem in greenhouse environments as spider mites are.
Hanging sticky traps around your plants and being vigilant should keep the population down. If you do find thrips in your greenhouse, use insecticidal soaps, neem oil, or pyrethrin sprays to wipe them out.
Q: I heard milk will kill thrips. Is this true?
A: Scientific studies are being done to investigate the use of milk in garden settings. An interesting paper was released from Punjab University in India which suggested that on roses, milk could help reduce the spread of aphids, thrips, and spider mites.
More study is still needed to compare milk’s use to other organic pest control methods. If you’re curious, you can read the study’s findings at this site.
If the terrible thrips have come to town, using one or more of the above methods should send them packing. Do you have thrips troubles? Tried something which we haven’t mentioned here? Share your stories in the comments below!