Plant Pests

Red Spider Mites: A Guide for Beginners

What are Red Spider Mites?

Red spider mites are tiny creatures that suck the sap from plants, causing damage to leaves and stems. They are commonly found on house plants and greenhouse plants, especially during hot, dry conditions.

Identifying Red Spider Mites

• Look for webbing: Fine, cobweb-like webbing on leaves and stems is a sign of red spider mites.
• Check for mottling: Brown or yellow spots on the upper surface of leaves can indicate mite damage.
• Use a magnifying glass: Examine the undersides of leaves for tiny, red or green mites and eggs.

Affected Plants

Red spider mites can infest a wide range of plants, including:

• House plants (e.g., poinsettias, orchids)
• Greenhouse plants (e.g., tomatoes, cucumbers)
• Outdoor plants (e.g., fuchsias, runner beans)

Getting Rid of Red Spider Mites

Increase humidity: Red spider mites thrive in dry conditions. Misting plants with water or placing them on a tray of pebbles and water can increase humidity and make it harder for mites to reproduce.

Use predatory mites: Predatory mites, such as Phytoseiulus persimilis, feed on spider mites and can help control infestations.

Use fatty acids or plant oils: If temperatures are too low for predatory mites, sprays containing fatty acids or plant oils can be used to kill red spider mites.

Tips for Prevention

• Inspect plants regularly, especially during warm, dry weather.
• Remove infested leaves and stems to reduce the spread of mites.
• Keep plants well-watered and avoid over-fertilizing, as this can make plants more susceptible to pests.

Additional Information

• Red spider mites are also known as two-spotted mites.
• They can turn orange-red in autumn and winter and hibernate in cracks and crevices.
• Affected plants may lack vigor and eventually die if the infestation is not controlled.