Posting this question for mom who has no internet...

Area is Tucson, AZ which I believe is zone 8.  She has several new fig trees that have been struggling to grown and just discovered grubs (she claims they are eating the roots, but not sure if that's confirmed or just what she was told).  The trees are planted in a zero-scape area, so nothing but dirt/rocks all around (no grass, which typically attracts grubs).

1. What is attracting the grubs, where did they likely come from?  Compost?

2. She found some sprays, but they are not organic and claim you cannot eat fruit for 1 year after treating.  There has to be something better out there that is organic/safer that doesn't have that long of a wait period!

Thanks in advance for any help!

Hi,
If you don't see damage to the trees ... Let the grubs alone.
What are the grubs doing ? Climbing on the trees ? Walking on the ground ?
If you see damage, Lime (from construction shops) and Coper-Sulfur sprays will help a lot.
If you have compost around, some grubs just feed on compost ... and won't harm the trees.

You could use the grub products made from bacteria. Gardens Alive sells two products for Japanese beetles. One is for lawn. I know you don't have lawn, or Japanese beetles. The product kills all beetle grubs. It is yet another strain of BT bacteria.
I would say yes the grubs are feeding on the roots. I don't know of a harmless grub? They all need to be killed! I never heard of grubs eating compost? I would like to see a reference for that! I know some are wood eaters, of decomposed wood. Those are fairly harmless., but moles like them just fine, raccoons too! Grubs also attract skunks, raccoons and moles who love to eat grubs! The damage would be bad if they started feeding on them. Such as digging all the roots up to find the feeding grubs, good luck!

Hi drew51,
You may need to unrust your French : http://www.guidescomposteurs.com/article.php?RefArticle=29

"cétoine dorée" is a green big shelled bug. Someone complained last week about finding some bugs resembling those on his overripe figs.

Actually there are two white grubs and the second you don't want it as it really feeds on roots. The first feeds on decaying wood, and compost of course.
http://www.guidescomposteurs.com/article.php?RefArticle=29

I know you asked for a spray but a more organic approach would be beneficial nematodes.  

https://www.dirtdoctor.com/garden/Grubworms_vq818.htm

Milky Spore. It is kind of expensive for a small amount but is supposed to be very good

Very interesting info, thanks everyone for the help!
So here is some more info from mom...

Problem: Very little root/branch growth, no leaves.... look like they are really struggling
Found grubs in soil of 7 trees... about 50 grubs were seen on one tree. All are focused in the root area of each

Affected trees:
2 large 7-8 footers
5 small trees 3 feet tall

Interesting excerpts from the Grub article...

Hi mulox,
I would say that the problem aren't the grubs.
Do you have pics of the trees ? Perhaps one can help by the look of the tree ...
If the trees look really sick... You may want to cut them at one foot/30cm of height and let them grow healthy root-suckers.
Sometimes it works better than trying to figure out what went wrong.
You could then root the cuttings for potted trees and see what goes better potted or in ground ...

As far as the beneficial nematodes, I would strongly contact the County Ag department (or Master Gardener group) for any follow up questions. The nematodes need to be put down at the right time of day and year to be effective.  They are sensitive to their environment (aka heat).  

Speaking of heat, when were the trees planted?  Any chance that this could be heat stress (I'm no Geography major but AZ gets hot doesn't it?) or transplant shock?  

I would also suggest amending the holes w/ some compost.  You had mentioned that "The trees are planted in a zero-scape area, so nothing but dirt/rocks...."  They could just be having a difficult time adapting to the zero-scape.  Compost would also be how I addressed any broken roots from digging around.   

before you go using any product the first step is to identify the problem and bug/grub. like others said they may not be the issue. just because you see a bug doesn't mean its bad. most of us are growing in nature and not a sterile lab. its all part of some cycle. if a plant is being attacked by bugs its most likely unhealthy. this is natures way of keeping the strongest offspring going.  I saw A BUG ON MY FIG LEAVES with damage. I didn't know what it was so I left it alone. after some research it turns out it was a lady bug larva. which probably came and ate the bug which cased the damage.

1. What is attracting the grubs, where did they likely come from?  

 they may come from decaying matter. try and figure out   which type of grub it is. this will probably explain more once you read about the grubs habits. then take it from there.

2 of the trees are very large and over 10 years old.
The other 5 are small and were planted last spring

Pictures will be difficult.... the garden is in a convent, so the nuns don't have access to cameras or internet.  
Possibly from a visitor... will see what I can do and post here if able.
Obviously that means identifying the type of grub will be equally difficult.

Right now she is very concerned about 1 tree... it's a young Peter's Honey.  She dug out all of the grubs by hand, but in doing so severely damaged many of the roots and now all of the leaves have fallen.
She is using a small amount of miracle gro and also going to try compost as well.

As for the other trees, she is going to wait and apply the nematodes to see what happens.