What are spider mites?
Spider mites are a common pest found on indoor and outdoor plants. These mites are typically reddish-brown or yellowish and have eight legs as adults. They can be hard to spot because of their size, with some describing them as smaller than a pin's head and similar to a tick.
Spider mites reproduce rapidly, with females laying numerous eggs on a plant, often in protective webbing. This quick reproductive cycle allows spider mite populations to explode under favourable conditions, causing significant damage to plants.
Signs you have spider mites
Fine webbing: Spider mites often produce fine silk webbing on the undersides of leaves, between stems, or on buds and flowers. These webs may appear as thin layers or intricate patterns.
Discolouration: Infested leaves may develop yellow, bronze, or silver speckles, which indicate cellular damage caused by feeding. Severe infestations can lead to extensive leaf discolouration and eventual leaf drop.
Small spots: Spider mites feed by puncturing the leaves and sucking out the goodness, leaving behind small, light-coloured spots on the upper surface of leaves. Over time, this damage can merge, leading to a mottled appearance.
Fine silk threads: If you gently shake a leaf over a white piece of paper, you may notice specks moving on the paper. These specks are the mites or their eggs, and they may appear as tiny dots or moving threads.
Visible mites: With severe infestations, you may see the spider mites themselves crawling on the plant leaves.
Seasonal patterns: Spider mites are most active during warm, dry conditions, so infestations often peak in summer. Keeping an eye on your plants during these times can help you detect mite activity early.
How to get rid of spider mites
In his Good Gardening weekly email, south Australian gardening icon Jon Lamb shares his wisdom on controlling spider mites.
“Sulphur, particularly wettable sulfur, provides effective control and is relatively soft on predators,” says Jon.
“Many gardeners are achieving good mite control by using one of the latest 'new age' products, including summer garden oils (pest oil, eco oil) as well as potassium-based products (Natrasoap and Eco Fend).
“These are not toxic to humans and have minimum effect on beneficial insects.”
These methods can also be used on aphids and white flies.