The curled rose sawfly also has one generation per year. The bristly roseslug has several generations throughout the summer. Sawflies often feed on the undersides of leaves, so inspect all leaf surfaces. Curled rose sawfly and leaf defoliation. Control Sawflies are best controlled when young.
Several options exist for control.
A physical tactic is to simply pick them off by hand. Dislodging them with a stick or a stream of water also works. If using water be sure to spray early enough in the day to allow foliage to be dry by sunset so as not to create favorable conditions for fungal development. Azadiractin is slower acting. Avoid spraying the rose flowers as many conventional insecticides are highly toxic to bees.