Red Spider Mite

Tetranychus urticae

Red Spider Mite, Two Spotted Spider Mite , Glasshouse Red Spider Mite

profile iconTetranychus urticae (4884149094)
by Gilles San Martin (CC BY-SA 2.0)
1 of 8
profile iconTetranychus urticae (4884149094)
by Gilles San Martin (CC BY-SA 2.0)
1 of 8
Tetranychus urticae, or red spider mite, is a tiny red arachnid, belonging to the Acari (mite) family, known as Tetranychidae. Mites are close relatives of ticks and spiders. They're barely visible with the naked eye. A tip to see if they are present on plants is to look for tiny, dusty cobwebs. In front of a light, they are easier to spot. They're common pests of greenhouse plants, where temperatures are warmer. They also are a frequent and annoying pest of houseplants. They have a broad host range, feeding on anything to vegetables, fruits and ornamental plants such as roses.
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Traits

Sucks plant cells from plants, resulting in yellow mottling and reduced photosynthesis.

Appearance

Adult: They're extremely small, yellowish-green or red-brown mites that you can barely see with the naked eye, hence they're fairly tricky to diagnose. The key is to monitor the plant symptoms. They measure below 0.4mm in length.

Symptoms

Fine, dusty webbing on foliage. Yellow mottling on leaves. Leaf yellowing. Dried up leaves. Premature leaf fall. Loss of vigour.

Activity

Diurnal

Personality

Order

Trombidiformes

Family

Tetranychidae

Metamorphosis

Incomplete

Distribution

Worldwide

Biological treatment

Raise humidity and ventilate glasshouses to increase air movement as this pest thrives in low humidity and high temperatures with little air movement. Within a heated glasshouse, year-round the predatory mite Phytoseiulus persimilis may be used as a form of biological control. It is very effective as it consumes spider mites at all stages of their life cycle. Likewise, predatory ladybugs or lacewing love to eat spider mites. If you see any in your garden, help them out and pop them on your infested greenhouse plants.

Chemical treatment

Bioneem / Biocure soprays are effective. However, there are many alternative and less harmful methods of control. If a chemical option is sought, check with your local garden centre and please take care to follow the manufacturers' instructions. Check with your local regulating body for guidance on active ingredients and their authorisation for use. Insecticidal soaps may be the next step following the above methods.

Attracts

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Knowledge and advice

Search our ever-growing knowledge base to find plants and information. Find out about pests and diseases you should be keeping an eye out for. Watch How to videos or follow step by step guides for tasks in the garden. Free download for your phone or tablet.
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