Thebordella,

I would just leave the green ties and support until the tree rooted well. The green ties are stretchy and you can remove them in the fall. If your place is too windy then you may need a bigger support next year.

Tony

I don't like those stakes that run straight up the trunk. They don't allow the tree trunk to gain strength. They are like a crutch. Sometimes you need a crutch (high winds, etc) but if it can do without I would. Regardless I would pull the stake out and if it has trouble standing on its own set the stake away from the trunk and use something to tie the stake to the trunk where there is a little give so the tree thickens/strengthens its trunk up.

While we are at it avocados don't like wet feet or our CA clay (I'm assuming zone 10 you are SoCal). You may want to mound it up or make a raised bed for it.