What is the cause of white spots on bean leaves and how to solve the problem?

Question

The leaves of my three bean plants are covered in these white spot; the rocket has the same problem, while the ivy and the avocado seem unaffected. These spots are located on the upper surface and they don't go away if I rub them.

I highly suspect that the cause is the grey fly in the picture below. I always found a dozen of them on each plant, especially on the lower surface of the leaf. They are 3mm long, grey, with black eyes and a pair of black spots on top of the thorax. They may have horizontal stripes, but given their size I'm not sure. According to my (attempted) research, they could be Psyllidae. Could they be the pest responsible of the damage?

The appearance of the lower surface makes me think that there could also be spider mites infesting my plants:

I was thinking of spraying a garlic infusion on the affected plants. Could it resolve the problem?

Location: Bologna, Italy.

Answer 1

It is leafhopper damage. In fact, you captured a picture of your particular leafhopper species in each of your photos. They are a sap sucking insect in the insect order Hemiptera - "true bugs". Once the damage is done to mature leaves there is nothing that will reverse the damage. There are garden insecticides that may help prevent future damage. You can check at your local garden center. Below are some links showing very similar damage on other plants.

http://jenny.tfrec.wsu.edu/opm/displayspecies.php?pn=360

http://plantanswers.com/Articles/SuckingInsects.asp

https://en.wikipedia.org/wiki/Leafhopper