Just a quick note of caution...many years ago I used Orthene to treat several plants for 'bugs' [scale & mealy bugs]. The bugs died... but the Pahlaenopsis that were sprayed produced deformed or stunted blooms for MANY year afterwards. Before the spraying... their blooms were normal. Others I have talked to also reported problems with Orthene and Phals. There are other remedies available... including oils and other organics. I do agree that Malathion is also a good choice... I've not had any problems with it's use.
Regards... Scotty.