Spinosid is said to be one of the safer insecticides, some even call it organic, although there is some new research it may not be as harmless to bees as we would like. I use it on my citrus to keep the leaf minors at bay and it works beautifully. Hopefully it will discourage the critters vectoring Greening too. You probably do not have pollinators in your GH so problems are unlikely but I have to apply it in the evening after the bees have gone to bed, by morning it is dry and safe for them.
