I thought 'Common name, I wonder if the UK and US things given it are the same?' I just had a quick look at 'UK sawflies' on Google, there are over 500 species !!
Not gone far in, but a UK website was suggesting leave them if they can be tolerated, they are part of a healthy garden diversity, but if they cause intolerable damage go for the caterpillars that are doing the damage. They suggest you do that manually and avoid poisons, I would suggest that if you find it distasteful a plastic glove to stop them squishing on your hands can help, I use one with slugs if i go out with a torch after them.