Glasshouse spider mite

Red spider mite

Question ...

I have a conservatory with many tender plants such as* Jasminum azoricum* and Plumbago capensis, which are in full flower. However, I have noticed the leaves losing their colour and their shine. Some look a little rust coloured. What can be the problem?

Answer ...

The culprit is the glasshouse spider mite - which can be a problem in greenhouses and conservatories when the atmosphere it kept too dry. Take a magnifying glass to the leaves and see if you can spot the very small spider-like mites. They are pale rust to neutral colour and may have produced webbing between the leaf stalk and the stem.

If this is what you have, make sure you water your plants well and mist at least twice a day with tepid water. Pot them up if they are pot bound, or repot in new compost where appropriate. A biological alternative is to introduce the predatory mite, Phytoseiulus persimilis. This predator requires a minimum day temperature of 20°C and night temperature of 16°C. It is available from mid April.

Garden Organic members can see our Glasshouse red spider mite factsheet for more information

Garden Organic members can see our expert factsheets for further advice on organic gardening. Access to factsheets requires a members' password.