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Red spider mites

Symptoms

Leaves and stems of plants covered in fine webbing. The upper surface of the leaf is mottled, while mites and eggs can be seen with a magnifying glass on the undersides of leaves. The plant may die.

Find it on: houseplants, greenhouse plants, also outdoors on fuchsias, runner beans, busy lizzies, grape vines
Time to act: all year round

Overview

These tiny, sap-sucking pests may be only 0.5mm long but they can wreak havoc in a greenhouse or on houseplants indoors. For most of the year they are a pale green colour with two dark spots on their back; it's only in autumn and winter that they turn orange-red. They thrive in hot, dry conditions so life in the greenhouse, or a centrally-heated home, suits them just fine. If the temperature stays above 12 celsius, they can breed all year round.


Solution

Leaves and stems of plants covered in fine webbing. The upper surface of the leaf is mottled, while mites and eggs can be seen with a magnifying glass on the undersides of leaves. The plant may die.

Organic

Improve air circulation in the greenhouse and boost levels of humidity by misting plants with tepid water and standing bowls of water on the benches between plants. Damping down the floor of the greenhouse with water will also help. When daytime temperatures in the greenhouse hover steadily around 21 celsius, you can try releasing the predatory mite, Phytoseiulus persimilis on to your plants. Alternatively, use sprays containing, fatty acids or plant oils.




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Talkback: Red spider mites
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Valdel 24/11/2011 at 15:28

My gunners which is planted by our pond, has developed a white powdery mildew for the third year in succession. What could be causing this & how can I prevent it recurring please?

davidt65 24/11/2011 at 15:28

will try the advise

mysterywoman196 24/11/2011 at 15:29

confirms my suspicions All the plants on my kitchen windowsill now have this :(

david spikes 24/02/2012 at 23:52

spider mites are an outdoor curse here in reno-the hot dry summers are perfect for them-soft evergreens(alberta spruce)can be killed in amatter of weeks-unfortunately people refuse to believe that they can be controlled and eliminated just by giving a sqirt with the hose whenever you go by-spraying chems is seldom effective

david spikes 24/02/2012 at 23:57

valdel-the way to eliminate powdery mildew is not to grow the plant-the climate and cultural conditions that let it flourish are difficult for gardeners to eliminate-some plants are resistant in some situations some are not