bugs in greenhouse

HI folks, I have noticed the last few days that my tomatillo plants had small brown like holes on the leaves I thought they were mabe water splash marks and the sun cooking them but I looked under the leaves today and there seems to be a mass of green blisters and I think they have some sort of bug in them. I have not grown tomatillos before so I'm not sure what they could be? everything else in the greenhouse is fine, a bit worrying though, does anyone have any ideas I would be greatful. :confused:

 

A guess, Flea beetle.

 

What is a flea beetle? and what can I do to get rid of them ? and here is another one, will it spread?

 

At least the ants have moved out,yipee!! :rolleyes: