The bottom of the leaves on most of my orchids have a dusty looking residue, with spots of reddish dust. Some of the leaves have started to go yellow and few have already dropped off.
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Never had a problem with my orchids before so didn't realise things had started to go wrong till nearly all the orchids were involved (mainly phals and dens).
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Anyone know what I can use to get rid of the mites, anything I'd have in the house or could buy in a local garden store (in the UK)..?
My orchids all sit on my front windowsill, with radiators underneath (the only place light enough to let them grow well).
Any help/advice would be appreciated.