What’s the problem?
I’ve noticed tiny webs and bugs on my orchid. Are these spiders, and will they harm my plant?
Diagnosis
Those tiny webs and minuscule bugs you’ve spotted on your plants sound like spider mites. These aren’t spiders but microscopic arachnids that thrive in dry, warm conditions, so you’ll notice they appear during summer heatwaves or winter months when central heating reduces humidity. They feed on plant sap, weakening the plant’s structure, which leads to yellowing leaves, discoloration and eventually leaf drop. They can multiply rapidly, posing a risk to your plant’s long-term health.
Prescription
Immediately isolate affected plants. Gently but thoroughly wash leaves and stems with a mild solution of soapy water to remove mites and their webs. Follow this by treating the foliage weekly with neem oil or an organic insecticidal soap spray. Raising humidity around the plant by misting, using pebble trays filled with water beneath pots, or employing a humidifier can also help reduce the likelihood of further mite infestations.
Prevention
Regularly inspect your plants, especially under the leaves and along stems, where spider mites prefer to hide and lay eggs. Maintain healthy humidity levels by grouping plants to create microclimates or misting foliage regularly. Implement good plant hygiene through regular watering practices and routine leaf cleaning.
Got a plant dilemma? Email saturday@theguardian.com with ‘Houseplant clinic’ in the subject line
