Pre-emptive approach to Boisduval scale

[ArronOB]

I have about 40 small cattleya hybrid plants growing on our windowsills in 3 or 4 inch pots (bark and charcoal with a few threads of sphagnum). They are in perfect health. In a couple of weeks we move to our new home, and they will be put outside where they will stay permanently, under some shelter. Average winter temperatures will be a bit low for outside growing, but they will get by. I'll set up an automatic watering system - daily in summer and weekly in winter.

Now I've grown cattleya hybrids in the past and I've learnt that in our environment the only real insect/arthropod pest is boisduval scale, but its very pervasive and very difficult to control. Id like to give them some type of pretreatment before putting them out.

I should point out that I'm not interested in solutions that involve rubbing the plants with alcohol or oil or soap or cotton buds or whatever. Past experience tells me that if I let the infestation start, itll be a loosing battle from then on.

I also find that with small plants like these I (clumsy) do too much damage handling them excessively.

A bit of Googling found a grower in Melbourne who claims to prevent scale completely by alternate spraying with Confidor and Diazanon. I wouldn't mind using the Confidor but I would be reluctant to use something as toxic as Diazanon.

If nothing else arises, I'll probably just give them 3 weekly treatments with Confidor before putting them out then hope for the best. At least its systemic, but I suspect there are better approaches as I've been told the scale will simply develop resistance to this product over time.

Any other suggestions ??

cheers
Arron