How to Kill Spider Mites

Co-authored by Lauren Kurtz

Last Updated: October 12, 2020 References

Spider mites are tiny insects that are difficult to see with the naked eye and can wreak havoc on the plants in your garden or lawn. If you suspect that you have mites, you should confirm that you have them before attempting to remove them. Once you know that they are on your plants, you can eliminate the bugs with plain water from a garden hose, or you can use a horticultural oil to remove and prevent more serious infestations.

Method 1

Method 1 of 4:

Spotting Signs of Spider Mites

1
Look for yellow or brown dots on your plant's leaves. Spider mites will weaken your plant, and the leaves will often form small yellow or brown dots. You may also notice leaves drying up and falling off your plant.^{[1]
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2
Examine your plants for webbing. Spider mites will leave webs under the leaves and stems on the plant. Look at your plants daily to see if there is webbing on any of your plants.^{[2]
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3
Search for mites with a magnifying glass. Since spider mites are less than 1 mm in size, they can be hard to see with the naked eye. Purchase a magnifying glass from a department store or online and examine the leaves on your plants. If you see small specks moving on the leaves, there's a good chance you have spider mites.^{[3]
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4
Shake your plant's leaves over a white piece of paper. If you don't have a magnifying glass, you can use a white sheet of paper to see the mites. Hold a piece of paper under the leaves of your plant and then shake them. If you see green, brown, or black specks start to move over the surface of the paper, you have spider mites.^{[4]
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- You can also crush the bugs with your finger. If they streak green, they are plant-feeding mites. If they are orange or yellow, they are probably beneficial predators.

Method 2

Method 2 of 4:

Removing Mites with Water

1
Isolate the affected plants. If you notice that you have spider mites and want to minimize their damage to your plants, it's best to separate the mite-infested plants. Move them to a different part of your garden or indoors before you try to remove them.^{[5]
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2
Spray down your plants with a hose. Water from a hose is strong enough to kill spider mites. Point a hose towards your plants and spray the leaves down with cold water. Remember to spray under the leaves as well so that you kill all of the mites.
3
Repeat the process once a week. Keep the mite infested plants isolated for at least a month so that the spider mites don't spread to your other plants. Water from a hose is not strong enough to destroy spider mite eggs, so spraying the plants down once a week for a month will ensure that you kill the new mites that are hatching.

Method 3

Method 3 of 4:

Using Horticultural Oil

1
Dilute horticultural oil with warm water in a spray bottle. Horticultural oils are oil-based products that smother insects and their eggs. You can purchase horticultural oil at a home and gardening store or online.^{[6]
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- Use traditional horticultural oil in the summer.
- Use dormant horticultural oil in the fall and spring.^{[8]
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2
Move the plants with the mites inside a garage or shed. Horticultural oil may be affected by rain or high humidity and moving them inside will help prevent this. Avoid using horticultural oil on maple trees, hickory trees, cryptomeria, and spruce trees and read the instructions to make sure that they are safe to use on your plants.^{[9]
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3
Thoroughly spray the plants with the oil. Since water and oil separate, it's important that you shake the bottle regularly as you use it. Saturate the top and bottom of the leaves with the oil. Allow the oil to soak in and kill the mites and their eggs.^{[10]
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- Horticultural oil works by suffocating the mites, so it's important you get complete coverage.
- Do not use the oils on flowers because it could damage them.
4
Spray every 2-3 weeks until the mites are dead. Check for spider mites periodically throughout the rest of the week. If you notice that mites are still hatching, spray the plant down again.^{[11]
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Method 4

Method 4 of 4:

Preventing Spider Mite Infestations

1
Prune affected portions of your plants. If you notice webbing on branches or spots on your leaves, you should prune these parts of the plant with hand pruners or shears. Discard the infested parts of the plant in the trash.^{[12]
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- Throwing away mite infested portions of a plant near your garden may spread mites to other plants.
2
Mist your plants with cold water. Moisture will keep mites away from your plants. Moving the plants indoors and misting them with water 2-3 times a day will reduce the likelihood of mites infesting the plants. You can also keep the plants over a saucer of water to prevent your plants from attracting mites.^{[13]
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3
Place a humidifier near your plants. Spider mites thrive in dry conditions, and a humidifier will help keep them away. Do not use a humidifier when applying horticultural oils.^{[14]
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Community Q&A
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Question

Do spider mites bite you?

Lauren Kurtz
Professional Gardener
Lauren Kurtz is a Naturalist and Horticultural Specialist. Lauren has worked for Aurora, Colorado managing the Water-Wise Garden at Aurora Municipal Center for the Water Conservation Department. She earned a BA in Environmental and Sustainability Studies from Western Michigan University in 2014.

Lauren Kurtz

Professional Gardener

Expert Answer

Support wikiHow by unlocking this expert answer.

No, spider mites won't bite humans. They are harmless to humans but can be damaging to plants.
Question

How do I get rid of spider mites on my plants?

Lauren Kurtz
Professional Gardener
Lauren Kurtz is a Naturalist and Horticultural Specialist. Lauren has worked for Aurora, Colorado managing the Water-Wise Garden at Aurora Municipal Center for the Water Conservation Department. She earned a BA in Environmental and Sustainability Studies from Western Michigan University in 2014.

Lauren Kurtz

Professional Gardener

Expert Answer

Support wikiHow by unlocking this expert answer.

Spray the plants with a natural or chemical insecticide. For a natural method, mix a small amount of dish soap into water and spray the tops and bottoms of the leaves. Regularly mist the leaves with plain water to prevent future spider mite infestations.