Do you see the ants cutting leaves? Or are they just tending aphids?

What exactly do the damaged leaves look like?

What exactly do the yellowing leaves look like, and are they evenly distributed on the plant?

Thanks for the reply.

The yellow leaves are at the bottom of the plant working their way upward. There are no leave cutting ants - just small ants. The new leaves are coming in small and irregular in shape with curled edges.

I have some photos at the URL listed.

Thanks :)

Here is a link that might be useful: Rugosa photos

Thanks.

The ants are not a concern. They are probably milking aphids. I think I see some aphids in the new-foliage shot. If aphids previously encrusted the growth tip, they can cause some distortion of the ensuing foliage, but this is not a serious concern. You might want to wipe the aphids off when you see a heavy concentration.

I would not be too worried about the yellow and brown leaves either since they are at the bottom of the plant. Are those angular holes appearing in the green leaves above as well, or do you see white transluscent "windows"? If so look on the undersides for small green worms (rose slugs) and wipe them off. I don't know what killed the leaves, possibly something chewed through the central leaf stem to kill the tissue above it in that v-shape.

Maybe someone from New England will have a better idea.

As Michael stated the ants are not a problem, they are busy collecting the pests you do have on the plant. Recent research shows that ants do not "milk" aphids as once though but take them (the aphid) back to their nest to feed the workers and larva in the nest and the aphids are devoured there. To help get rid of the aphids use a strong water stream (a spray bottle produces a stream strong enough) to knock the buggers off the plant. Since there are already several generations of aphids on the plant you will need to repeat this as often as necessary to get control. Look closely and often to see what else may be causing problems.

Thanks for your responses!

I'll wipe the plants off and go from there!

somewhat of topic-- but ants do in fact milk aphids. If you sit and watch for a few minutes you can see them stroke the aphid with their antena, and the aphid will excrete a drop of honeydew. if you tickle an aphid with a blade of grass, they will occasionally do it for you as well. its sweet

As for the rugosa, have you sprayed anything on the foliage? Blanc double de coubert lost all its leaves once after I sprayed it with miracle gro ( it seemed like a good idea at the time :)

Not to drive the thread off topic, but I'm curious about the ants too. Everything I've read says to control ants in order to control aphids since the ants will protect the aphids from natural predators. I'd really like to know if I'm doing the wrong thing. Could you post a link to this recent research? Or cite a source? Thanks.

Can't tell for sure from the pictures but look carefully for little bumps on the canes. I suspect there might be a few scale on the canes. They look like just little lumps and will pop if you press on them with a thumb. If so Pop all you can find and keep a good eye out as the ants do show up with them.

At my last home I did this every two days to my rose and the flowering almond as well as the peach tree. Ants brought them to the peach tree and then I looked good around on the other plants. I'd pop all I could then rubbed the leaf joint with q-tips of alcohol. I did that religiously for one season and followed up in early spring for any straglers. Never had them after that and the ants left too.