The green rose slugs usually only last a couple weeks, at which time the good predator bugs show up and get rid of them.

If you don't want to wait that long, just look at the backside of some chewed leaves. Squint--and when you see the teeny, tiny green "worms," just squish them--or if you are squeamish, toss them in the yard. They aren't likely to find their way back.

Between your hand-picking and the predator bugs showing up, you really don't have to spray at all.

As for powdered mildew, give the roses a good spray and "wash off" the mildew. Water the plants well. They don't usually have this problem unless they are too dry. You shouldn't have to spray for this also.

As to rose chafers, I have no idea. I think I basically just pretend they are not there.

Kate

And, some roses will mildew in their first year or so, when they are immature plants -- then become more resistant as their root structure grows.

Time and good watering will often cure this ill.

Yes I've noticed some areas only get Rose Slugs for a short time depending on how many generations they produce.
Some areas Rose Slugs will and can cause major foilage damage too.

Here we have Rose Slugs from May until November.( six months)... So every area of the country is different in the length of time that Rose Slugs hang around...

My suggestion is to pick and squish as Kate mentions in her post and just watch and see how long your rose slugs stay around in your area and see how much damage they cause. ( Each year will be different.)
Picking and squishing may be enough for you.
If not Safers Insecticidal Soap works. (Follow Directions)

I have a small Mister Lincoln rose bush in a container and this is what I seen the other day while checking him. lol.. I just picked them off...

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