Greenie Get the app Speckled leaves and fine webbing
How to get rid of spider mites on houseplants
Spider mites are tiny sap-sucking relatives of spiders that thrive in warm, dry indoor air, leaving leaves finely speckled and sometimes webbed. Isolate the plant, then wash both sides of every leaf with a strong spray of water and repeat daily if you can. If mites keep coming back, use insecticidal soap or horticultural oil, covering the leaf undersides and repeating as the label directs.
Check these first
-
Look at the upper side of the leaves for a fine pale stippling, as if dusted with tiny dots, that later turns yellow or bronze.
-
Turn the leaves over and check the undersides with a magnifying glass: mites look like moving specks, often with tiny pale egg shells and cast skins.
-
Hold a sheet of white paper under a leaf and tap it. Specks that crawl across the paper are mites; dust stays still.
-
Look for fine silk webbing between leaves and stems, a sign of a heavy infestation.
-
Check nearby plants too: mites spread easily from one plant to the next.
Causes and fixes
-
Warm, dry indoor air
How to tellMites appear or flare up when the heating comes on in autumn and winter, or on plants near radiators and sunny glass. In warm conditions a new generation can develop in under a week.
What to doMove the plant away from heaters and hot glass and raise the humidity around it, for example with a humidifier or by grouping plants. Rinse the leaves regularly, which mites dislike.
-
An active infestation on the leaves
How to tellStippled leaves, specks on the undersides and webbing at the tips.
What to doSeparate the plant from the others. Wash it in the shower or sink with a firm spray, aiming at the leaf undersides, and wipe large leaves with a damp cloth. Repeat daily if you can, and keep going until no new speckling appears, because new mites keep hatching from eggs.
-
Mites that survive washing
How to tellFresh stippling and moving specks keep returning after several rinses.
What to doSpray with insecticidal soap or horticultural oil labelled for houseplants, wetting the undersides of every leaf, because these only kill mites they touch. Repeat at the interval on the label. Do not spray a dry, wilting plant or one in hot sun; water it first. Avoid broad-spectrum insecticides, which can make mite problems worse.
-
A stressed or newly bought plant
How to tellMites show up on a plant that has been underwatered or recently brought home, then spread to its neighbours.
What to doKeep new plants apart from your collection for a few weeks and check them closely. Water and feed according to the care sheet, because stressed plants are hit hardest.
Stop it coming back
-
Shower or wipe your plants every few weeks, including the leaf undersides.
-
Keep mite-prone plants away from radiators and hot, dry spots, and raise humidity in winter.
-
Quarantine new plants for a few weeks before placing them with others.
-
Check leaf undersides with a magnifier whenever you water during the heating season.
When to worry
When to worry
A few speckled leaves caught early clear up with washing and patience. Worry when webbing covers shoots, when many leaves turn yellow or bronze and drop, or when mites keep returning after several weeks of treatment. A plant that is mostly covered is often best thrown away: bag it first so the mites do not spread to other plants. For large collections or conservatories, predatory mites sold as biological control are an option.
