Thrips are very small bugs that can do a lot of damage to houseplants. Once thrips get established, they reproduce quickly and can be hard to get rid of. But if you keep at it and use the right treatment methods, you can get rid of them and keep them from coming back. This complete guide will teach you everything you need to know about how to treat thrips on houseplants.
What Are Thrips?
Thrips are very small slender insects that are often black or brown in color, but can also be yellowish or greenish. They have narrow bodies long fringed wings, and move quickly over plant surfaces.
An adult thrips is only about 1 to 2 millimeters long, so they can be hard to see with the naked eye. Thrips larvae are even smaller.
Thrips feed by piercing plant cells and sucking out the contents. This results in silvery or bronze scarring, dead patches, and distorted growth on leaves and flowers. They prefer new growth and tender plant tissues.
Signs of a Thrips Infestation
Here are some of the most common signs that thrips may be present on your houseplants:
- Silver or bronze spots or scars on leaves and flowers
- Black dots of fecal matter on leaves
- Stunted or distorted new growth
- Flowers that fail to open or are malformed
- White or gray speckles on leaf undersides
- Damaged leaves that turn brown and die
Pay close attention to the veins and undersides of leaves, as this is where thrips like to hide. Look for the tiny bugs that are moving around and the damage they do.
Where Do Thrips Come From?
Thrips can hitchhike indoors on new plants, enter through open doors or windows, or come in when bringing outdoor plants back inside. Some common ways thrips invade houseplants include:
- New plants purchased from a nursery or store
- Houseplants that spent the summer outside
- Fresh cut flowers or vegetables brought inside
- Blowing in from outdoor plants through open windows and doors
Thrips spread very quickly between houseplants that are in close contact. So isolating any infested plants is important to stop them from invading your whole collection.
Thrips Life Cycle
Thrips go through multiple life stages during their lifecycle: eggs, larvae, pupae, and adults.
- Adult females lay eggs into plant tissue.
- Eggs hatch into larvae which feed on the plants.
- Larvae drop into the soil and go through a pupal stage.
- Adult thrips then emerge from the soil and fly back up onto the plants to feed and lay more eggs.
The entire lifecycle can be completed in just two weeks. Thrips also reproduce asexually, so a single female can give rise to many offspring very rapidly. This allows thrips populations to explode quickly.
How to Get Rid of Thrips on Houseplants
Getting rid of thrips takes patience and persistence. Usually, it takes several treatments spread out over a few weeks to end their lifecycle. If you want to get rid of thrips naturally, follow these steps:
Isolate Infested Plants
Keep any plants that show signs of thrips away from your other houseplants right away. This helps prevent them from spreading.
Wash Plants
Give infested plants a good rinse to wash away some of the adults and larvae. Use room temperature water and take care not to overwater the soil. Wipe leaves (especially the undersides) with a damp cloth to further dislodge thrips.
Apply Insecticidal Soap
Insecticidal soap is effective at killing thrips on contact. Spray all plant surfaces, including the undersides of leaves. Let the soap sit for 5-10 minutes before wiping leaves clean. Repeat every 3-5 days for a few weeks.
Use Neem Oil
Neem oil kills thrips and also acts as a repellent. Mix neem oil with water according to label directions and thoroughly spray plants. Repeat treatments every 7-10 days for several weeks.
Apply Systemic Insecticide
Systemic insecticides are taken up by the plant’s roots and make its tissues toxic to feeding insects. Apply as a soil drench and repeat as directed on the product label, usually every 2-4 weeks.
Set Out Sticky Traps
Yellow or blue sticky traps will catch adult thrips flying around. Place traps near infested plants and monitor to help reduce the population.
Be Patient and Persistent
It takes repetition and consistency to break the thrips life cycle. Don’t give up too soon! Keep treating and monitoring until all signs of thrips are gone. Expect the process to take 4-6 weeks.
How to Prevent Thrips on Houseplants
Prevention is the best way to avoid disastrous thrips infestations. Here are some tips:
- Quarantine and closely inspect any new plants before introducing them
- Isolate plants that were outdoors for the summer for a few weeks before moving inside
- Regularly check houseplants for pests
- Provide good air circulation between plants
- Keep plants away from open doors and windows
- Clean plants with water to wash away potential pests
- Apply neem oil preventatively every 2-3 weeks in problem areas
Catching thrips early when populations are small makes them much easier to control. So vigilance and routine monitoring are key.
Frequently Asked Questions About Thrips on Houseplants
How do you know if you have thrips?
Look for tiny black or brown insects moving quickly on leaves, especially along veins and leaf undersides. Signs of damage like distorted growth, silver scarring, dead patches, and black fecal dots also indicate thrips are present.
What kills thrips on houseplants?
Insecticidal soap, neem oil, and systemic insecticides are most effective at killing thrips. Sticky traps can also help reduce adult populations. Strong water pressure can dislodge some thrips.
Do thrips lay eggs in soil?
Thrips pupae develop in the soil. Adult females then lay eggs into plant tissue above ground. Thrips don’t actually reside in the soil for long. Removing all of the soil generally isn’t effective against thrips.
How do you get rid of thrips permanently?
Getting rid of thrips for good requires treating repeatedly using different methods like insecticidal soap, neem, and sticky traps over the course of several weeks. This breaks their lifecycle at different stages. Maintaining vigilance and taking preventive measures are also key to keeping thrips away long-term.
Can thrips kill plants?
Thrips rarely kill mature plants, but they can stunt growth and damage foliage and flowers. Young seedlings or small plants can decline and die from heavy thrips damage. Keeping thrips under control is important to prevent serious harm to houseplants.
The Bottom Line
Thrips can be challenging pests, but don’t let them get the best of your houseplants! Now that you know what to look for and how to treat thrips effectively, you can take action at the first signs of damage. Combining different organic control methods and persistence is the proven way to get rid of thrips and keep them from coming back.
