Blueberry Insects in Portugal 1
I am not that familar with the insects of Portugal. The "C" shaped grub is a beetle grub. Here in the United States it could be Japanese Beetle, a Root weevil, or several other beetles that might feed on the roots or leaves. The beetle on the plastic mulch is a Ground beetle a predator of other insects and considered a beneficial insect. The leaf notching could be leaf feeding by root weevil adults or another insect. You should see if you can find a local insect authority it see if these require treatment. I cannot make any pesticide recommendation for Europe as I do not even know what is legal or the Trade Names of pesticides in Portugal.