| Dear tillystuff,
The pics you've posted are not of mildew. It is bosduval (sp?) scale. This kind of scale loves Cattleya types and are a bugger (no pun intended) to get rid of. I have never been able toeradicate them completely, only more or less ocntrol them. I have found systemic insecticides to be the most effective against them. They ingest a systemic insecticide via the plants sap and are killed that way. Topical insecticides are much less effective. This kind of scale loves heat. They show up on my Cattleyas (and to a much lesser extent my Cymbidiums) in summer and I spray and spray and spray, then in winter, they completely vanish only to reappear again the next summer. They like to colonize around the rhizome of the plant in a protected area like inder the potting mix or beneath a dead bract. I recommend a thorough cleaning of the plant, removing all dead bracts, unpotting the plant and removing all visible scale form the rhizome and roots , also thoroughly clean the plant itself, removing all visible scale (use a soft toothbrush to get in those tight areas like in the second pic. Repot and begin treating aggressively, preferably with a systemic. Keep this plant away form your other plants and check frequently (as in every few days) and carefully for any signs of return removign all signs of scale if you see any more. I don't want to sound like an alarmist, this plant may very well survive, but don't mess around with these guys.
Good luck!  |