Spider Mites

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Red Spider mites (Tetranychus urticae) attack most greenhouse, conservatory and houseplants, targeting initially individuals that are stressed, windward, next to vents/openings. The mites are only just visable to the naked eye and can be found mainly on the underside of the leaves where they feed by sucking sap. Initially olive green with two dark spots then, when fertile, they become red. The early symptom of damage is a fine speckling of the upper surfaces of affected leaves, usually younger, tender leaves. As the infestation develops the foliage becomes yellow or a dull pale green and the older leaves start to dry up and fall. At this stage the mites produce a fine silken webbing between the leaves, and large numbers of them may swarm over the highest parts of the plant. Red spider mites thrive in hot dry conditions, so maintaining a humid atmosphere during infestations may deter pests.

Spidermites are usually carried into rooms on clothing, or though open vents on air currents.  For clones, most infections come from the mother.  Once infection has occured, the area should be stripped and cleaned before replanting, eggs are resistant to a wide range of controls are often seen as a pink mist in crevices, etc.  Treat with organic spray, then introduce Phytoseiulus predatory mites (heavy infections), Amblyseius predatory mite (preventative or light infections) or Ladybird sp., however, biocontrols need to be used before the pest population explodes and/or flowering has commenced.  Chick weed is an important host, so should be removed from vicinity.