From our cultural programme : "Uncle Al's stories"
Julius Caesar refferred to Gaul as "Hairy Gaul" (la "Gaule chevelue"). Not because the inhabitants had a different hairstyle than the clean-cut Roman troops, but because the territory he conquered was covered in forests.
Another thing he mentionned about the locals was that they reeked of garlic. Yet, garlic was used in "Italy" too, but it seems the Gauls used it even more profusely.
Garlic is excellent for blood circulation, preventing or curing colds, etc. but it's also a very good organic pest-killer (don't ask why, ask the critters).
Two or three heads boiled in water and left to infuse for a day, then filtered, is very efficient against aphids.
If you keep your trees indoors, there is another good organic trick : 1 full tablespoon of ground cinnamon in 10 centiltres of 70% alcohol and 90 centilitres of water. Leave it to rest for 24-48 hours, filter, and spray. Cinnamon is also good against root-rot and deters cats from doing what we don't like them to do in our plantations.
I used This cinnamon mixture with success, but of course, it was on a very limited scale.