I’ve searched for fig tree ailments (and there are many!) but can’t find a match for my problem. Can anyone help? Many of the leaves look like this - the leaf bulk has been eaten away and there is left either a hole, or a fine white mesh (I guess leaf veins). I don’t see any rolled leaves, aphids, ants, bulbous areas on either side of leaf, no brown or yellow anywhere. We are in the south of France. Ideas??
It'll be an insect, or the larvae of an insect, that has caused this skeletonizing on the leaves. If you haven't spotted any caterpillars or other creatures feeding during the day, then take a torch out at night and inspect what's going on after dark. It may be too late to see the cause - if you had a few larvae, they may by now have pupated or even hatched out into whatever insect (moth, sawfly) they turn into as adults.
I looked up in my big bonsai guide what can cause these holes in leaves of trees. Two options came up, either caterpillars or Vine weevils (Otiorhynchus sulcatus).
With a search on google to see how the holes differ from the two options, I find the pattern caterpillars leave more like your pictures than the ones made by weevils.
The weevil seems to start from the side of the leaf and eats through the veins, but the caterpillar eats from the middle and tends to skip the nerves, leaving those meshes like your picture. So I think it are caterpillars, of some kind, maybe you can find any (or they are already pupae).
Personal anecdote: I’ve seen damage like this from water fall off an asphalt roof, onto a plant at the base of the wall. Consider nearby physical causes of damage - in the anecdotal case the water was harsh enough to cause damage, but gentler damage than a full rip/tear.
It's a tiny caterpillar. I had exactly the same one and could see the web-like covering. Just scrape that off if you can or treat with an appropriate insecticide. As it's a fig you may prefer not to use insecticide, or your tree may be too big.
Sorry I can't help with identifying the actual caterpillar, but mine was green striped and about 1.5 mm (.05 in) wide and 5mm (.19 in) long, so very small.
Having done a little more research, the Tortrix moth caterpillar seems to provide a fairly good fit. I wonder if the OP would care to comment?
