If they show up, it is usually by mid/end of June. I'd say if your leaves aren't completely eaten up by now, you're safe. It hasn't been warm for an extended period this spring (as opposed to last year), which has kept them away. Since it's your first time growing potatoes, you get the benefit of the beetles not overwintering in the soil or in any surrounding foliage from the prior year's harvest. After 2 years in the ground, I'm growing potatoes in fabric bags on my deck for the first time. Great conversation piece!

Kevin