Jim, I also have rose slug damage as one of the costs of not spraying insecticide but the damage is so minor as to be not a problem in the broad scheme of things. Perhaps 1/100th of one percent of leaves have some damage. I also pick the little buggers and feed them to the fish in my pond. I would rank rose slugs as probably no higher than the 20th worst problem for rose growers.

We seem to get very high numbers of those things here. They will shred the leaves and leave only naked stems. lol

I'm another who never has serious damage. When I look under damaged leaves to squish them, usually the wasps have already picked them off. But they do serious damage in some gardens.

oh yes I caught a few of them yesterday, mine were a little bit bigger and you are right, the bigger they are left to grow the more damage they do. First they start out just with small skeletal holes and then start eating big holes through the leaf. I hate squashing these with my fingers so I put them on the ground and step on them.
They are really a small nuisance compared to the thrips and JBs though.

Yea, I just posted this so others that wondered what was eating holes in there rose leaves could see what they were and know where to find them. And by watching them I can learn more about them myself. lol

I remember seeing tons of JB's around here many years ago, but, haven't seen those things around for 10-15 years now.
Have not encountered Aphids yet.
Never seen any thrips, these in warmer climates only? Right?

these in warmer climates only? Right?

No, there are species of thrips in PA that will damage rose flowers. The one that's wreaking havoc in Florida, chilli thrips, is not known to be in PA and will probably never establish itself there because the climate's too cold for it, but there are other species of thrips that can handle cold weather just fine.

For instance, wheat thrips is a wheat (not rose) pest found in all of Europe except its very coldest regions.

Wasps and/or hover flies seem to keep my population of rose slugs down. I do have them, but not nearly as much damage as a few years ago. When I have noticed them getting a little too much on certain roses, I start lifting up leaves to the underside and squishing them or rubbing them off.

It sort of amazes me how much a tiny rose slug can eat. lol

I've seen yellow jackets on our roses, not sure what there doing though.

Thanks York Rose on the thrip info!

Maybe I should just let them eat the more mature roses and see if in the future any type of predator builds up enough to fight them off. Birds here only come when they are big fat and juicy, by then leaves are stripped. lol
I will hand pick and protect the smaller bands though until they mature.

Your yellow jackets are hunting rose slugs.

I was wondering what all those yellow jackets were so interested in Greenhaven. I suspected, but , couldn't find any info directly linking yellow jackets to rose slugs.

Today I've decided to officially adopt the KARL METHOD of insect control.
I'm looking the other way. lol. And letting the good insects come and do the job. lol.

greenhaven's right. In the context of a garden in late spring/early summer, yellow jackets are predators looking for insects to feed to their young back in their nest.

(Hopefully that nest is on someone else's property. Yellow jacket nests are usually underground. They often use old mouse or other rodent tunnels. As long as you're not near the nest you don't really have anything to fear from a yellow jacket at this time of year, provided you don't get so close to it that it perceives itself to be threatened. If it's all by itself and obviously hanging around your flowers it's looking for prey, so leave it alone so it can help itself and you at the same time.)

Yellow Jacket nest is not on our property. Thank God! Funny thing is i've never been stung by one, even though they like to buzz around me, land on me all the time when i'm outside for the last many, many years. I don't bother them and they seem to leave me alone, so far.
Yes, I know they are agressive and can sting more than once.
I've seen my friend accidently disturb a nest and man can those things attack. Wow! He had bees down his pants, inside his shirt, in his sox. ouchhhhhh!

Yellow jackets are hornets.

In the eastern part of the USA (maybe the western part, too, but I don't know since I've never lived there or learned about that region's wasps), the hornets collectively (in the Northeast there are three or four species of them) are the most aggressive (ie., most given to aggressive "stinging" defensive behavior) of the stinging wasps (there are far more species of wasps that don't sting humans, either because they have no stinger or because their stingers are too short and weak to pierce human skin).

In the Northeast yellow jackets (the eastern North America species is Vespula maculifrons, but there is another species in the West) are the most aggressive of those hornets.

(Ignore the phrases in parentheses & you'll get the gist of my message, then go back and read the parenthetical phrases and you'll learn more. I've always talked in long, complicated sentences full of dependent clauses............... ;) )

Hornets, that explains why so agressive. Some parts of the season they seem more agressive than others.

I've seen some smaller, tiny bees on the rose leaves also. I'm seeing all kinds of strange insects. lol. They do not look like any bad insects listed.

I seen some small shiny colored bodied insects with fly wings on the leaves. Wonder what they are?

Wonder what they are?

Post some pictures and I'll see what I can do. I make no promises about giving you species names, but I might be able to give you a general idea of what you're seeing.

I've seen some smaller, tiny bees on the rose leaves also.

There are MANY species of solitary bees, and most of them are very small. They're probably interested in collecting rose pollen to feed to their babies. It's not unusual for bees like this to collect pollen & nectar, make a ball out of the pollen (using the nectar as the binding agent), lay an egg on the ball, and then seal the whole thing inside a chamber and do it all over again in the next part of the tunnels they've already created. Native solitary bee species often live that way. The babies take a year to become adults, and so show up the following year to repeat the cycle.

Some parts of the season they seem more agressive than others.

Yellow jackets are more aggressive in late summer/early autumn because their source of food in the nest is diminishing. After they feed those killed insects to the babies back in the nest the babies secret a sugary fluid which the adults eat as food. That works great at this time year since the nest is growing in population and so there are more babies on the way then there are adults now (creating a situation in the nest where the adults have access to lots of food). By the end of the summer the queen isn't laying so many eggs as now, and so there are lots of adults, but fewer babies to rear (and thus less food in the nest for the adults). That means the adults have to look for sugary stuff outside the nest to satiate their hunger. That's why they become an aggressive nuisance at Labor Day cookouts & picnics.

Well, that explains it about the yellow jackets. I screwed up on taking pics of 2 different insects already. Both were way out of focus. Either one gave me a second chance. lol

Ok, i've been trying to understand the life cycle of the rose slug.
What i've gathered so far, but, not sure if accurate.

Ok, the sawfly lays eggs in the slith of rose leaves, several weeks later the eggs hatch. Sawfly larvae (rose slugs) feed on the leaf tissue for about a month, then drop into the soil to pupate.
Does this sound anywhere near accurate???

Ok, if there is second or third generation: When does this happen?

I have more questions then answers. lol

According to the UNIV. OF MINNESOTA and many other articles there are 3 types of rose slugs that eat rose foilage.
Regular rose slug (1 generation), Bristly rose slug (several generations), Curled rose slug (1 generation).

http://www.extension.umn.edu/distribution/horticulture/components/6953_01.html

Our rose slugs are here from May to Sept. So, i'm guessing one at least is the Bristly Rose Slug.
Not sure if it's only one type or more types here?
I've seen them curled on the leaves, but, do they all curl when threatened? lol
The ones I've seen in Aug/Sept of last year had orange heads.
The ones i'm seeing right now are very tiny with black heads/face. Not sure if the face color changes with age or not?
Things just do not make sense to me. It's hard learning about insects. lol

At this point you may well know more than I do. I would not be surprised to learn there is more than one species of sawfly in the USA whose larvae feed on roses.

Here's some rose slug damage in the first pic, by looking on the underside of the leaves, that's where they will be.
We have some so small you can barely see them with the naked eye.

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See the tiny holes in the leaves on the bottom right side. I used a flash so the holes would show up better.

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Above my thumb is a tiny rose slug.

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Rose Slug Damage:

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Just a nice bloom pick to make you forget about rose slugs. lol

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I just noticed the broom in the background. lol
See blooms make you forget about everything. lol

Ok, I think I got things figured out after finding a site with info and pics I was looking for.

http://www.sactorose.org/rosebug/irosepests.htm#ROSESLUGS

The rose slug we have right now is the Bristly Rose Slug.
The rose slug we had last season around Aug/Sept was a curled (coiled) rose slug.
So, we do have 2 differeny types here.

Hey Jim- I'm having lots of Rose slug damage right now - I live in Michigan and the Damage happened really fast so I read up on it and they say to spray the leaves really hard with a hose to get them off- if that doesn't work I might try something stronger but I'm getting holes in leaves and also skeletal looking leave damage- I saw the little buggers today and killed a couple with my fingers- you were asking about natural predators of these little guys and I read that ladybugs will eat them and I didn't know you could actually order ladybugs! It's so discouraging because my roses just started coming out and I've already got this problem- last year later in the year we had a ton of Japanese beetles that we had to deal with!

Yes you can try and hose off rose slugs or pick them off and squish them...

Our rose slugs are grow up to 3/4" or so here...lol...So mainly wasps, birds will eat them here...

The least toxic spray would be something like safers insecticide soap...Follow directions to be effective...

Best way to keep ahead of rose slugs is to leap into action as soon as you first start seeing damage...