How to Kill Tiny Spiders Under Leaves
The arachnids that infest the undersides of plant leaves are spider mites. These relatives of spiders pierce individual plant cells with their mouth parts, feeding on the contents. Spider mite feeding results in yellow or white spots forming on the leaves. Heavy infestations cause discolored or stunted plants and may be fatal. Treat spider mite infestations as soon as you see evidence of them on plant leaves. Does this Spark an idea?
Things You'll Need
- Paper towel
- Magnifying glass
- Water hose
- Predatory insects
- Insecticidal soap
- Horticultural oil
- Miticide
Instructions
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Inspect plants regularly for spider mite damage, including white or yellow speckles on the leaves and tiny moving dots on the undersides of the leaves. Shake a leaf over a piece of white paper to dislodge a few for further inspection through a magnifying glass.
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Spray heartier plants with a forceful stream of water from a hose. This technique, called syringing, dislodges the spider mites from the plants but does not harm beneficial insects. Take special care with using this method on more sensitive plants.
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Purchase and release predatory insects such as lady beetles and parasitic mites for biological control of spider mites.
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Spray plants thoroughly with insecticidal soap or horticultural oils. Insecticidal soaps and horticultural oils kill spider mites without harming beneficial insects. Spray insecticidal soaps in the warm season. Spray horticultural oils at the rate of 1 to 2 percent in the warm season to kill active spider mites and at the rate of 3 to 4 percent in the cool season to kill eggs and dormant adults.
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Spray plants with a miticide if the gentler controls have not worked. Malathion, chlorpyrifos, diazinon and dicofol are over-the-counter miticides available to the homeowner. Stronger miticides are only available to licensed professionals. Miticides may harm beneficial insects.
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Tips & Warnings
Prevent bringing spider mites into the garden by inspecting new plants for evidence of spider mites before purchasing.
