I have several year and a half old in ground black mission trees here in Lake Havasu. Our temps here get a bit hotter than in the valley, I think.

None are painted, and all appear healthy with no bark peeling or other signs of deterioration. Two of them are over four feet tall allready. They're tough little guys.

I would suggest you mulch real heavy (as in 4-6 inches deep for several feet around your tree) though. Fig trees tend to be shallow rooted. Unmulched ground temps can get pretty high in our 110+ degree summers.

Dave

Also...if it were my tree, I would leave the shoot. I train all trees with several leaders....three or four at least. The bushier shape makes for a wider tree with more low leaves to provide shade for both the exposed bark and the ground beneath the tree.

That's how I do it and it has worked for me so far.
Hopefully thisisme will chime in here as well with his advice. He's been doing this in our climate a while longer than I have.

If you are really concern about the sun, instead of painting the trunk I would wrap it with white colored tree warp. Sun doesn't affect the bark on my fig trees and temps can reach 100F here.
During winter I do wrap the trunk of my crimson queen japanese maple, apple and Persimmon trees.

white colored tree wrap,

http://www.amazon.com/Dewitt-3-Inch-50-Foot-White-TW3W/dp/B0016AJC0W/ref=sr_1_1?ie=UTF8&qid=1307030987&sr=8-1

Thank you both for your responses. It seems I don't need to paint it then. I have mulched it to about 4" so that's a good thing.

nkesh099, you do wrap your persimmon tree so I guess I should paint my persimmon tree then?

I do not like to paint any of my trees, if I would paint them my neighbors would think I am crazy. I do wrap them with white colored tree wrap only in winter and will take them off by March-April. I do not wrap them in summer.

Navid.