Ah….those JBs are a right pain in the you know what. I experienced them last year en masse, when I planted cannas in the backyard.
I have been told the bags mentioned above, only brings more of them into your yard. The key to getting rid of them apart from the hand picking method, is to try and plant things they aren’t attracted to, which doesn’t leave you much to plant :-)
I’ll love to have climbing roses on my hand-built pergola, but am not willing to take the risk of an infestation.