I have about 3 trees with suckers that I want to remove and grow. Is it too late in the season? My success rate with removing and growing suckers is around 5% and one tree is my favorite tree that did not come back after this winter it does have 3 10-18 inch plants I just want to save the species type thing. They are all inground here in zone 6b/7

sounds like good candidates for air layering. You still have time.

I've only done one sucker. It was this time or a little later last summer.
100% success rate. I  made sure to take it off the mother plant at the point of sprouting so as to get as much of its own root system as I could. I trimmed off most of the leaves, kept it covered in plastic dome, and in shade for about a month, before bringing it back out into the sun. The plant did not do much in the way of putting out new growth for the rest of the season. It did fine this spring. 

Grant
z5b 

No reason not to air layer and leave on until next year and seperate when dormant.

I would just mound up a few inches of soil around them and wait until next spring, or try an air-layer. Actually an air layer is probably best since the tree might have RKN. It is a tough time of year to be a plant with no roots though so I would not try to dig them now.

Dan just pull them down to the ground remove the leaves and cover with soil and place a brick on top to hold it down. Only allow the tip of the sucker to be exposed. this will allow it to grow roots under the soil then in about 6-8 weeks cut the sucker from the main plant only allowing the new roots to feed the tree until it goes dormant then dig and pot presto new tree.

You can dig suckers up at this time of year and pot them up.  I have done this before and it worked.  It helps to start the potted suckers in the shade and work them back into full sun slowly.  It only works if you can dig up suckers with some decent roots.

Well thanks guys.
My problem with the air layer is they are all green wood
My problem with al's method is I am afraid that they are too brittle and would snap. I am kinda stuck between a rock and a hard place. Maybe I should try all three techniques one for every branch. But if I loose them that is it. Maybe I should just wait and take cuttings this fall?

Try making a partial cut into the stem near the roots, but leave it attached. Maybe put  something in the cut like a tooth pick to keep seperated and see if roots develop. I am doing that with one of mine right now and have done so successfully in the past.

Barry then what pile up soil around the area?

Yes try to cover the cut with soil

I don't remmeber, but I think I asked this before. Anyway... Is a sucker any branch that comes out of the ground off the trunk or is it only branches in the ground that have roots? Do you need to remove suckers or can you leave them?

Suckers are branches coming off of the tree below the soil line.  But the part that is below soil grows its own roots.  If you cut the sucker deep enough in the soil you can get its roots and treat it like a rooted cutting.

I have a Peter's Honey fig that has put all of its energy into growing suckers. The main trunk has nearly stopped growing while the suckers have put on about 24 inches. At what point should I intervene? Has anyone else noticed this problem?

I have noticed that with my trees that the branches coming up from the ground are growing way faster.

I see the same tendency for the lower branches to outgrow the top. I suppose what you do about it depends on whether you ultimately want a bush shape or a standard tree shape, and whether it's growing in a pot or in the ground. Others may have different opinions on this, but I always assumed that more branches and foliage meant more photosynthesis, which would mean more energy going into root growth and fruit. To me, more branches near the ground means more fruit within easy reach.

You guys all have good points.
I also want to add that when a tree is Fig M virus infected,the old trunk is in bad shape and show a lots of disease,while the new sucker coming from ground has healthy leaves.
Of course keeping the healthy sucker and eliminating the old infected wood is the way to go.
In another scenario,that happen in cold climates,the main trunk get partially damaged by frost in past winter.
It looks stressed,with similar symptoms as FMV.
Of course letting new  trunks grow from base is best for plant.

If I wanted to try to get another tree from a sucker how would I do that?