How to Kill Spider Mites in Potted Plants

Potted plant leaves turn pale and wilt when spider mites attack.

The tiny spider mite -- just 1/50 inch long -- causes more problems on indoor potted plants than most other insects combined. They thrive in dry, dusty indoor conditions. In large numbers, the spider mites feed on leaves and plant cells, causing discoloration and damage. In some cases, a fine web appears over the leaves. A few methods exist to help you kill spider mites in potted plants.

Things You'll Need

• Syringe or spray gun
• Insecticidal oil
• Cloth

Instructions

Syringing

1. Fill a large household syringe or spray gun with water. Ensure that the syringe or gun delivers a strong jet of water when you press down on the pump or lever.

2. Aim for the underside of the potted plant leaves affected with spider mites. Spray a jet of water at each leaf in turn. Hold a plate or tray underneath to catch the water and mites the spray washes off.

3. Spray all the leaves on the plant. Repeat the process every few days for two weeks. This should be enough to get rid of most low-level spider mite outbreaks on small to medium potted plants.

4. Rub the leaves of your potted plant with a damp, clean cloth frequently once the spider mites have disappeared. This prevents a buildup of dust -- something spider mites love.

Oils and Chemicals

1. Apply insecticidal or horticultural oil to a clean rag. Wipe the rag over the leaves, both top and bottom, of your potted plant.

2. Cover every bit of the plant surface area to bring as many mites as possible in contact with the oil. Spider mites that don't touch the oil may survive.

3. Spray a pesticide containing bifenthrin if you want to make sure to kill all the mites. However, follow the package instructions and don't use a product not listed as safe for indoor plants.

Tips & Warnings

• The earlier you detect the mites, the better. Hold a piece of white paper beneath any plants you suspect contain mites. Shake the plant. You'll see tiny moving creatures on the paper if spider mites are present.

• Low-rate horticultural oil of 1 to 2 percent is less effective in the fall and spring. Use a higher rate oil to kill spider mite eggs.

• Ensure that any insecticides you buy contain miticide, or the product may not kill spider mites.

References

• University of Minnesota Extension; Houseplant Insect Control; Jeffrey Hahn, et al.; 2005
• Colorado State University Extension; Spider Mites; W.S. Cranshaw, et al.; November 2006
• Ohio State University Extension Fact Sheet; Spider Mites and Their Control; David J. Shetlar
• Colorado State University Extension; Managing Houseplant Pests; W.S. Cranshaw; November 2006